FIELD OF THE INVENTION
[0001] The present disclosure relates to the field of communication, and particularly, to
an optical signal power control method and device, and an optical line terminal.
BACKGROUND
[0002] With increasing demands on bandwidth of users, passive optical network (PON) technology
in the access field is also constantly updated. From EPON (Ethernet Passive Optical
Network), GPON (Gight-Capable Passive Optical Network) to 10GEPON, XGPON, and to NGPON2,
as well as the 100GEPON under research and development, bandwidth in the access technology
is constantly increased. However, the increase in bandwidth brings about a problem
of insufficient power budget, because too many users on the access network requires
a high power budget to make receiving of light powers at both a central office and
a terminal meet sensitivity requirements and achieve good transmission performance.
In order to meet the power budget requirements, an optical amplifier is required.
Optical amplifiers commonly used in current communication systems are Erbium-doped
Optical Fiber Amplifiers (EDFAs) and Semiconductor Optical Amplifiers (SOAs). Due
to advantages including a relatively flat and wide gain spectrum, fast dynamic response,
and integratability, SOA has attracted more and more attention and become a good choice
for optical amplifier components in the optical access field.
[0003] However, a dynamic range problem is present in the PON system. Due to different light
transmitting powers of different optical network units (ONUs), and different distances
from different ONUs to an optical line terminal (OLT), the OLT receives different
light powers of different ONUs. If the SOA maintains the same gain, it may cause insufficiently
amplified receiving light of some ONUs that fails to meet the OLT sensitivity requirements,
while causing excessively amplified receiving light of some other ONUs that leads
to overload of the OLT and even damages to an OLT receiver. Therefore, a mechanism
to control an output light power of the SOA is required so that the SOA can reasonably
adjust the gain according to different incident light powers, or to add a variable
attenuation after the SOA to make the emitting light have a relatively uniform power.
[0004] US 2009/208227 A1 discloses a passive optical network system, wherein the receiver of the OLT has a
data table related to a time slot information and required gain information and to
register the required gain, a new ONU has to send a registration request; If no registration
request is transmitted during a cycle, the OLT increases the gain of the SOAs, if
a registration request is received the gain is adjusted one step lower.
CN 101 350 670 A discloses the generation of control information comprising time slots and a list
of amplification gain values according to the distance from each ONU to the OLT
[0005] In view of the related art, no effective solution has been proposed yet regarding
the problem of equalizing uplink burst signal amplification in an optical network
unit (ONU).
SUMMARY
[0006] In order to solve at least the problem of equalizing uplink burst signal amplification
in an ONU, an optical signal power control method and device, and an optical line
terminal are provided in the embodiments of the present disclosure.
[0007] The invention is as defined in claims 1-15.
[0008] In the present application, acquiring different time points when uplink optical signals
of optical network units (ONUs) arrive at an optical signal amplifier or a variable
optical attenuator; establishing a correspondence relationship between an ONU ID and
a power control factor of the uplink optical signals; and performing power control
on the uplink optical signals according to the different time points and the correspondence
relationship, the uplink burst signals of the ONU are amplified to a range receivable
by the OLT receiver, thereby solving the problem of equalizing uplink burst signal
amplification in an optical network unit (ONU) in the related art, and achieving the
technical effect of reducing requirements on the receiving power range of the OLT
receiver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The drawings described herein are intended to provide a further understanding of
the present disclosure, and are intended to be a part of the present disclosure. The
exemplary embodiments of the present disclosure and the description thereof are for
explaining the present disclosure and do not constitute an undue limitation of the
present disclosure. In the drawings:
Fig. 1 is a flowchart of an optical signal power control method according to an embodiment
of the present disclosure;
Fig. 2 is a schematic diagram (I) of an optical signal power control structure according
to an embodiment of the present disclosure;
Fig. 3 is a system block diagram during ONU registration according to an embodiment
of the present disclosure;
Fig. 4 is a flowchart (I) of ONU registration according to an embodiment of the present
disclosure;
Fig. 5 is a flowchart (II) of ONU registration according to an embodiment of the present
disclosure;
Fig. 6 is a schematic diagram (II) of an optical signal power control structure according
to an embodiment of the present disclosure;
Fig. 7 is a schematic diagram (III) of an optical signal power control structure according
to an embodiment of the present disclosure;
Fig. 8 is a flowchart (III) of ONU registration according to an embodiment of the
present disclosure;
Fig. 9 is a flowchart (IV) of ONU registration according to an embodiment of the present
disclosure;
Fig. 10 is a flowchart (V) of ONU registration according to an embodiment of the present
disclosure;
Fig. 11 is a flowchart (VI) of ONU registration according to an embodiment of the
present disclosure;
Fig. 12 is a schematic diagram of a multi-channel optical signal power control structure
according to an embodiment of the present disclosure;
Fig. 13 is a schematic diagram (I) of a multi-channel optical signal power control
structure according to an embodiment of the present disclosure;
Fig. 14 is a schematic diagram (II) of a multi-channel optical signal power control
structure according to an embodiment of the present disclosure;
Fig. 15 is a schematic diagram (III) of a multi-channel optical signal power control
structure according to an embodiment of the present disclosure;
Fig. 16 is a schematic diagram (IV) of a multi-channel optical signal power control
structure according to an embodiment of the present disclosure;
Fig. 17 is a schematic diagram (V) of a multi-channel optical signal power control
structure according to an embodiment of the present disclosure;
Fig. 18 is a structural block diagram of an optical signal power control device according
to an embodiment of the present disclosure;
Fig. 19 is a structural block diagram (I) of an optical signal power control device
according to an embodiment of the present disclosure;
Fig. 20 is a structural block diagram (II) of an optical signal power control device
according to an embodiment of the present disclosure;
Fig. 21 is a structural block diagram (III) of an optical signal power control device
according to an embodiment of the present disclosure;
Fig. 22 is a structural block diagram (IV) of an optical signal power control device
according to an embodiment of the present disclosure;
Fig. 23 is a structural block diagram (V) of an optical signal power control device
according to an embodiment of the present disclosure; and
Fig. 24 is a structural block diagram (VI) of an optical signal power control device
according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0010] The disclosure will be described in detail below with reference to the drawings in
conjunction with the embodiments. It should be noted that the embodiments of the disclosure
and features therein may be combined with each other in any manner as long as they
are not contradictory.
[0011] It should be also noted that terms "first", "second", and the like in the description,
claims and drawings of the disclosure are used for the purpose of distinguishing similar
objects instead of indicating a specific order or sequence.
Embodiment 1
[0012] In this embodiment, an optical signal power control method is provided. Fig. 1 is
a flowchart of an optical signal power control method according to an embodiment of
the present disclosure. As shown in Fig. 1, the flow includes the following steps
S102 to S106:
At step S102, different time points when uplink optical signals of optical network
units (ONUs) arrive at an optical signal amplifier or a variable optical attenuator
are acquired.
At step S104, a correspondence relationship between an ONU ID and a power control
factor of the uplink optical signals is established.
At step S106, power control is performed on the uplink optical signals according to
the different time points and the correspondence relationship.
[0013] In this embodiment, the application scenarios of the foregoing optical signal amplification
method include: a Passive Optical Network (PON). In this application scenario, acquiring
different time points when uplink optical signals of optical network units (ONUs)
arrive at an optical signal amplifier or a variable optical attenuator; establishing
a correspondence relationship between an ONU ID and a power control factor of the
uplink optical signals; and performing power control on the uplink optical signals
according to the different time points and the correspondence relationship, the uplink
burst signals of the ONU are amplified to a range receivable by the OLT receiver,
thereby solving the problem of equalizing uplink burst signal amplification in an
optical network unit (ONU) in the related art, and achieving the technical effect
of reducing requirements on the receiving power range of the OLT receiver.
[0014] It should be noted that, in this embodiment, the number of optical signal amplifiers
includes but is not limited to: one or more than one; and the number of variable optical
attenuators includes but is not limited to: one or more than one.
[0015] Optionally, in the embodiment, the optical signal amplifier is mainly described taking
a semiconductor amplifier (SOA) as an example.
[0016] The present embodiment will be exemplified below with reference to specific examples.
[0017] As shown in Fig. 2, a time point when each ONU uplink signal arrives at the SOA may
be acquired by DBA (Dynamic Bandwidth Allocation). At that time point, an SOA gain,
or an attenuation of a variable optical attenuator (VOA) behind the SOA, or both the
SOA gain and the VOA attenuation, are adjusted by a DBA-based output power control
module, thereby amplifying the ONU uplink burst signals to a range receivable by the
OLT receiver to obtain an amplified effect and reducing requirements on the receiving
power range of the OLT receiver.
[0018] Optionally, the above power control factor includes, but is not limited to, a gain
of the optical signal amplifier, and an attenuation of the variable optical attenuator.
[0019] In an optional implementation of the present disclosure, when the power control factor
is a gain of the optical signal amplifier, the step of establishing the correspondence
relationship between the ONU ID and the power control factor of the uplink optical
signals includes the following steps S11 to S12:
[0020] At step S11, a registration time slot is allocated and a downlink registration signal
is transmitted.
[0021] At step S12, when the ONU receives the downlink registration signal and determines
that a power requirement of the registration time slot is met, registration and establishment
of a correspondence relationship between the ONU ID and the gain of the optical signal
amplifier are started.
[0022] Through the above steps S11 to S12, the uplink burst signals of the ONU are further
amplified to a range receivable by the OLT receiver, thereby solving the problem of
equalizing uplink burst signal amplification in an optical network unit (ONU) in the
related art, and achieving the technical effect of reducing requirements on the receiving
power range of the OLT receiver.
[0023] Optionally, when the power control factor is a gain of the optical signal amplifier,
the step of establishing the correspondence relationship between the ONU ID and the
power control factor of the uplink optical signals includes the following steps S13
to S15:
At step S13, a registration time slot is allocated and a downlink registration signal
is transmitted, wherein the downlink registration signal includes gain information
of the optical signal amplifier.
At step S14, when the ONU receives the downlink registration signal and determines
that the downlink registration signal is in a registration time slot with a minimum
gain of the optical signal amplifier, the gain of the optical signal amplifier is
increased until a serial number transmitted by the ONU is correctly received.
At step S15, a correspondence relationship between the ONU ID and the gain of the
optical signal amplifier is established.
[0024] In an optional implementation of the present disclosure, when the power control factor
is attenuation of the variable optical attenuator, the step of establishing the correspondence
relationship between the ONU ID and the power control factor of the uplink optical
signals includes the following steps S21 to S22:
[0025] At step S21, a registration time slot is allocated and a downlink registration signal
is transmitted, wherein the registration time slot is pre-assigned an attenuation
value.
[0026] At step S22, when the ONU receives the downlink registration signal and determines
that a power requirement of the registration time slot is met, registration and establishment
of a correspondence relationship between the ONU ID and the attenuation of the variable
optical attenuator are started.
[0027] Through the above steps S21 to S22, the uplink burst signals of the ONU are further
amplified to a range receivable by the OLT receiver, thereby solving the problem of
equalizing uplink burst signal amplification in an optical network unit (ONU) in the
related art, and achieving the technical effect of reducing requirements on the receiving
power range of the OLT receiver.
[0028] Optionally, when the power control factor is an attenuation of the variable optical
attenuator, the step of establishing the correspondence relationship between the ONU
ID and the power control factor of the uplink optical signals includes the following
steps S23 to S26:
At step S23, the attenuation of the variable optical attenuator is set to maximum.
At step S24, a registration time slot is allocated and a downlink registration signal
is transmitted, wherein the downlink registration signal includes attenuation information
of the variable optical attenuator.
At step S25, when the ONU receives the downlink registration signal and determines
that the downlink registration signal is in a registration time slot with a minimum
actual gain of the optical signal amplifier, the attenuation of the variable optical
attenuator is decreased until a serial number transmitted by the ONU is correctly
received.
At step S26, a relationship between the ONU ID and the attenuation of the variable
optical attenuator is established.
[0029] In an optional implementation of the present disclosure, when the power control factor
is a gain of the optical signal amplifier and an attenuation of the variable optical
attenuator, the step of establishing the correspondence relationship between the ONU
ID and the power control factor of the uplink optical signals includes the following
steps S31 to S32:
At step S31, a registration time slot is allocated and a downlink registration signal
is transmitted, wherein in the registration time slot, the optical signal amplifier
is provided with a pre-assigned gain, and the variable optical attenuator is provided
with a pre-assigned attenuation.
At step S32, when the ONU receives the downlink registration signal and determines
that a power requirement of the registration time slot is met, registration and establishment
of a correspondence relationship between the ONU ID, the gain of the optical signal
amplifier, and the attenuation of the variable optical attenuator are started.
[0030] Through the above steps S31 to S32, the uplink burst signals of the ONU are further
amplified to a range receivable by the OLT receiver, thereby solving the problem of
equalizing uplink burst signal amplification in an optical network unit (ONU) in the
related art, and achieving the technical effect of reducing requirements on the receiving
power range of the OLT receiver.
[0031] Optionally, when the power control factor is a gain of the optical signal amplifier
and an attenuation of the variable optical attenuator, the step of establishing the
correspondence relationship between the ONU ID and the power control factor of the
uplink optical signals includes the following steps S33 to S36:
At step S33, an actual gain of the optical signal amplifier is set to minimum.
At step S34, a registration time slot is allocated and a downlink registration signal
is transmitted, wherein the downlink registration signal includes actual gain information
of the optical signal amplifier.
At step S35, when the ONU receives the downlink registration signal and determines
that the downlink registration signal is in a registration time slot with a minimum
actual gain of the optical signal amplifier, the gain of the optical signal amplifier
is increased until a serial number transmitted by the ONU is correctly received.
At step S36, a correspondence relationship between the ONU ID, the gain of the optical
signal amplifier, and the attenuation of the variable optical attenuator is established.
[0032] In an optional implementation of the present disclosure, a plurality of optical signal
amplifiers or variable optical attenuators are provided. When a plurality of optical
signal amplifiers or variable optical attenuators are provided, a plurality of correspondence
relationships are provided, wherein each of the plurality of correspondence relationships
is a relationship between each channel of ONU IDs and a power control factor of the
corresponding uplink optical signals.
[0033] Optionally, before reaching the plurality of optical signal amplifiers and/or variable
optical attenuators, the uplink optical signals are subjected to corresponding power
control via a shared optical signal amplifier.
[0034] The present embodiment will be exemplified below with reference to specific examples.
Embodiment I
[0035] This embodiment is divided into two steps. In a first step, a relationship between
the ONU ID and the SOA gain is established in a registration stage. In a second step,
a dynamic gain adjustment table is established with reference to DBA and according
to the obtained relationship, wherein a DBA-based output power control module dynamically
adjusts the SOA gain according to the table so that powers of the optical signals
emitted by each of the ONUs are amplified, and the amplified powers tend to be the
same.
[0036] In the first step, a correspondence relationship between the ONU ID and the SOA gain
is established.
[0037] Since power values of the uplink optical signals of each ONU that reach the SOA are
unknown at the beginning, the suitable SOA gain for each ONU uplink optical signal
cannot be determined. In PON standards, a dynamic range of the ODN may be up to 15
dB, and a fluctuation range of the light transmitting power of the ONU may be up to
5 dB. As a result, a difference in the light powers reaching the OLT receiver may
be up to 20 dB. If the SOA gain is set too small, some ONUs with greater signal attenuations
to the OLT cannot be registered. However, if the SOA gain is set too large, some ONUs
with smaller signal attenuations to the OLT may have excessively amplified light powers,
thereby damaging the OLT optical receiver. Therefore, a suitable method is needed
to enable the OLT to correctly receive uplink burst information from the ONU with
an appropriate gain, record the ONU ID and the SOA gain value at that time, and establish
a relationship between the two. Two ONU registration methods are provided below.
[0038] Fig. 3 is a system block diagram during ONU registration. As shown in Fig. 3, the
OLT includes a medium access layer (MAC), a DBA module, a light emitting module (Tx),
a light receiving module (Rx) capable of measuring a light power, a filter for filtering
noises of SOA amplified spontaneous emission (ASE), an SOA, and a DBA-based output
power control module. The DBA-based output power control module may consist of a memory,
a controller and a driver. The memory is used for storing a dynamic gain adjustment
table, according to the dynamic gain adjustment table, the controller controls the
driver to drive the SOA and change the SOA gain. The controller may also directly
receive a command from the OLT to adjust the SOA gain.
[0039] A first ONU registration method: as shown in Fig. 3, the OLT allocates registration
time slots in segments. In each time slot, the SOA has a pre-assigned gain that is
set according to a power range that may be incident on the SOA and a receiving light
power range of the OLT receiver. For example, provided that a system dynamic range
is 20 dB, an incident light power range on SOA is [-40 dBm, -20 dBm], and a receiving
power range of the OLT receiver is [-28 dBm, -8 dBm], then two registration time slots
may be allocated in segments, and each of the two registration time slots correspond
to the pre-assigned SOA gain values of 10dB and 15dB, respectively. In this way, the
ONU corresponding to the incident power on SOA of [-40dBm, -30dBm] may be registered
in the time slot with an SOA gain of 15dB, and the ONU corresponding to the incident
power on SOA of [- 30dBm, - 20dBm] may be registered in the time slot with an SOA
gain of 10dB. In a certain registration time slot, the OLT allocates a gain to the
SOA through the DBA-based output power control module and transmits a downlink signal
containing the light transmitting power information of the OLT, and notifies an eligible
ONU to transmit an uplink signal. The eligible ONU refers to an ONU in which a value
obtained by the ONU transmitting power subtracting uplink attenuation, that is, the
incident power value on SOA, falls into a power range specified by the time slot.
With a known light transmitting power of the OLT, the ONU calculates the uplink attenuation
according to the received downlink optical signal power. The uplink attenuation is
obtained by the light transmitting power of the OLT subtracting a downlink optical
signal power value received by the ONU. Then, the ONU determines whether the uplink
light power to the SOA meets the power requirement of the allocated time slot based
on a value obtained by a light transmitting power of a transmitter of its own subtracting
the value of the uplink attenuation, if not, waits for the next allocated time slot;
if yes, transmits an uplink ONU serial number to start registration. The uplink signal
is amplified by the SOA with the pre-assigned gain and then filtered by the filter
to remove ASE noises. The receiver receives the filtered signal, measures the light
power of the same, and converts the optical signal into an electrical signal to be
transmitted to the MAC. The OLT records the gain value of the SOA and the ONU ID at
this time, completes the registration, and establishes a relationship between the
ONU ID and the SOA gain. The flowchart is shown in Fig. 4.
[0040] The established relationship between the ONU ID and the SOA gain is shown in Table
1.
Table 1
| ONU-ID |
Gain [dB] |
| 1 |
G1 |
| 2 |
G2 |
| 3 |
G1 |
| 4 |
G2 |
| 5 |
G2 |
| ... |
... |
| n |
Gn |
[0041] A second registration method: the OLT assigns a minimum gain, for example, 5dB, to
the SOA through the DBA-based output power control module, and then allocates the
registration time slot and transmits a downlink registration signal including a current
SOA gain value. After receiving the registration signal, the ONU determines whether
the registration signal is in the registration time slot with the minimum SOA gain,
if yes, transmits uplink serial number information; if no, waits for the registration
time slot with the minimum SOA gain. The uplink optical signal is amplified by the
SOA, and filtered by the ASE filter before being received by the OLT receiver. If
the OLT receives correctly, the current ONU ID and SOA gain value are recorded to
establish a relationship between the ONU ID and the SOA gain; if the OLT fails to
receive correctly, the OLT increases the SOA gain by a fixed value, for example, 5dB,
and the above steps are repeated. After the SOA gain is increased to a certain value,
the OLT may correctly receive the ONU uplink signals. At this time, the ONU ID and
the SOA gain are recorded to establish a relationship between the ONU ID and the SOA
gain, and then the registration is completed. The flowchart is shown in Fig. 5.
[0042] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the SOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID and the SOA gain
obtained from the registration process, as shown in Fig. 2, so as to adjust the SOA
gain value dynamically by the DBA-based output power control module so that each of
the ONUs tends to have the same burst optical signal power.
Table 2
| ONU-ID |
Time point of arriving at OLT |
Burst duration |
Gain (dB) |
| 1 |
t1 |
a |
G1 |
| 2 |
t2 |
b |
G2 |
| 3 |
t3 |
c |
G1 |
| 4 |
t4 |
d |
G2 |
| 5 |
t5 |
e |
G2 |
| ... |
... |
... |
... |
| n |
tn |
n |
Gn |
[0043] Optionally, during the registration stage, the OLT may fine-tune the SOA gain according
to the received ONU light power so that the uplink light power reaches an optimal
receiving power of the OLT receiver, for example, -18 dBm, after being amplified by
the SOA. Then, the ONU ID and the SOA gain at this time are recorded so that each
ONU has a one-to-one SOA gain. In this way, the uplink optical signals of each ONU
may be amplified to a consistent optimal receiving power of the OLT receiver. As shown
in Fig. 6, the gain equalization amplification module in Fig. 6 can be composed of
the components of Fig. 2. The burst optical signals of different ONUs obtain a light
power adjusted to the optimal receiving power of the OLT receiver after being amplified
by the gain equalization amplification module, thereby increasing the power budget
while greatly reducing requirements of the OLT receiver on the dynamic bandwidth range.
Embodiment II
[0044] A value of the VOA behind the SOA is dynamically adjusted according to the DBA. Optional
Embodiment II is similar to Optional Embodiment I except that the receiving power
of the OLT receiver is adjusted by adjusting attenuation.

[0045] The DBA-based output power control module may consist of a memory, a controller and
a stepping motor for adjusting VOA attenuation.
[0046] In a first step, a relationship between the ONU ID and the VOA attenuation is established.
[0047] A first ONU registration method: as shown in Fig. 7, the SOA is operated at a fixed
gain, and the OLT allocates registration time slots in segments. In each time slot,
the VOA has pre-assigned attenuation that is set according to a power range that may
be incident on the SOA and a receiving light power range of the OLT receiver. For
example, provided that a system dynamic range is 20 dB, the SOA is operated at a fixed
gain of 20dB, an incident light power range on SOA is [-40 dBm, -20 dBm], and a receiving
power range of the OLT receiver is [-28 dBm, -8 dBm], then two registration time slots
may be allocated in segments, and each of the two registration time slots correspond
to the pre-assigned VOA attenuation values 10dB and 5dB, respectively. In this way,
the ONU corresponding to the incident power on SOA of [-40dBm, -30dBm] may be registered
in the time slot with a VOA attenuation of 5dB, and the ONU corresponding to the incident
power on SOA of [- 30dBm, - 20dBm] may be registered in the time slot with a VOA attenuation
of 10dB. In a certain registration time slot, the OLT allocates attenuation to the
VOA through the DBA-based output power control module and transmits a downlink signal
which notifies an eligible ONU to transmit an uplink signal. The eligible ONU refers
to an ONU in which a value obtained by the ONU transmitting power subtracting uplink
attenuation, that is, the incident power value on SOA, falls into a power range specified
by the time slot. With a known light transmitting power of the OLT, the ONU calculates
the uplink attenuation according to the received downlink optical signal power. The
uplink attenuation is obtained by the light transmitting power of the OLT subtracting
a downlink optical signal power value received by the ONU. Then, the ONU determines
whether the uplink light power to the SOA meets the power requirement of the allocated
time slot based on a value obtained by a light transmitting power of a transmitter
of its own subtracting the value of the uplink attenuation, if not, waits for the
next allocated time slot; if yes, transmits an uplink ONU serial number to start registration.
The uplink signal is amplified by the SOA with the fixed gain, attenuated by the VOA,
and then filtered by the filter to remove ASE noises. The receiver receives the filtered
signal, measures the light power of the same, and converts the optical signal into
an electrical signal to be transmitted to the MAC. The OLT records the attenuation
value of the VOA and the ONU ID at this time, completes the registration, and establishes
a relationship between the ONU ID and the VOA attenuation. The flowchart is shown
in Fig. 8.
[0048] The established form of the ONU ID and the VOA attenuation is shown in Table 3.
Table 3
| ONU-ID |
VOA attenuation [dB] |
| 1 |
A1 |
| 2 |
A2 |
| 3 |
A1 |
| 4 |
A2 |
| 5 |
A2 |
| ... |
... |
| n |
An |
[0049] A second registration method: the OLT assigns a maximum attenuation, for example,
10dB, to the VOA through the DBA-based output power control module, then allocates
the registration time slot and transmits a downlink registration signal including
a current SOA actual gain value (Equation 1). After receiving the registration signal,
the ONU determines whether it is in the registration time slot with the minimum SOA
actual gain, if yes, transmits uplink serial number information; if no, waits for
the registration time slot with the minimum SOA actual gain. The uplink optical signal
is amplified by the SOA, attenuated by the VOA, and filtered by the ASE filter before
being received by the OLT receiver. If the OLT receives correctly, the current ONU
ID and VOA attenuation value are recorded to establish a relationship between the
ONU ID and the VOA attenuation; if the OLT fails to receive correctly, the OLT decreases
the VOA attenuation by a fixed value, for example, 5dB, and the above steps are repeated.
After the VOA attenuation is decreased to a certain value, the OLT may correctly receive
the ONU uplink signals. At this time, the ONU ID and the VOA attenuation are recorded
to establish a relationship between the ONU ID and the VOA attenuation, and then the
registration is completed. The flowchart is shown in Fig. 9.
[0050] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the VOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID and the VOA attenuation
obtained from the registration process, as shown in Fig. 4, so as to adjust the VOA
attenuation value dynamically by the DBA-based output power control module so that
each of the ONUs tends to have the same burst optical signal power.
Table 4
| ONU-ID |
Time point of arriving at OLT |
Burst duration |
VOA attenuation (dB) |
| 1 |
t1 |
a |
A1 |
| 2 |
t2 |
b |
A2 |
| 3 |
t3 |
c |
A1 |
| 4 |
t4 |
d |
A2 |
| 5 |
t5 |
e |
A2 |
| ... |
... |
... |
... |
| n |
tn |
n |
An |
[0051] Optionally, during the registration stage, the OLT may fine-tune the VOA attenuation
according to the received ONU light power so that the uplink light power reaches an
optimal receiving power of the OLT receiver, for example, -18 dBm, after being amplified
by the SOA and attenuated by the VOA. Then, the ONU ID and the VOA attenuation at
this time are recorded so that each ONU has a one-to-one VOA attenuation. In this
way, the uplink optical signals of each ONU may be amplified to the same optimal receiving
power of the OLT.
Embodiment III
[0052] Embodiment III is similar to Embodiments I and II except that the receiving power
of the OLT receiver is adjusted by adjusting both the SOA gain and the VOA attenuation.
This has the advantage of reducing requirements on the adjusting range of the SOA
and the VOA.

[0053] The DBA-based output power control module may consist of a memory, a controller,
a driver for adjusting an SOA gain and a stepping motor for adjusting VOA attenuation.
[0054] In a first step, a relationship between the ONU ID, the SOA gain, and the VOA attenuation
is established.
[0055] A first ONU registration method: the OLT allocates registration time slots in segments.
In each time slot, the SOA is provided with a pre-assigned gain, the VOA is provided
with a pre-assigned attenuation, and a difference between the two is called an SOA
actual gain. This pre-assigned actual gain is set according to a power range that
may be incident on the SOA and a receiving light power range of the OLT receiver.
For example, provided that a system dynamic range is 20 dB, an incident light power
range on SOA is [-40 dBm, -20 dBm], and a receiving power range of the OLT receiver
is [-28 dBm, -8 dBm], then two registration time slots may be allocated in segments,
and each of the two registration time slots correspond to the pre-assigned SOA actual
gain values 10dB and 15dB, respectively. Accordingly, when the actual gain value is
10dB, the SOA gain may be 15dB, and the VOA attenuation may be 5dB; when the actual
gain value is 15dB, the SOA gain may be 17dB, and the VOA attenuation may be 2dB.
In this way, when the SOA or the VOA alone is desired to be adjusted by a range of
5dB, adjusting both of them may decrease the range to 2dB and 3dB. The ONU corresponding
to the incident power on SOA of [-40 dBm, -30 dBm] may be registered in a time slot
with an SOA actual gain of 5dB, and the ONU corresponding to the incident power on
SOA of [- 30dBm, - 20dBm] may be registered in the time slot with an SOA actual gain
of 10dB. In a certain registration time slot, The OLT assigns a gain to the SOA, and
attenuation to the VOA through the DBA-based output power control module, and transmits
a downlink signal that notifies an eligible ONU to transmit an uplink signal. The
eligible ONU refers to an ONU in which a value obtained by the ONU transmitting power
subtracting an uplink attenuation, that is, the incident power value on SOA, falls
into a power range specified by the time slot. With a known light transmitting power
of the OLT, the ONU calculates the uplink attenuation according to the received downlink
optical signal power. The uplink attenuation is obtained by the light transmitting
power of the OLT subtracting a downlink optical signal power value received by the
ONU. Then, the ONU determines whether the uplink light power to the SOA meets the
power requirement of the allocated time slot based on a value obtained by a light
transmitting power of a transmitter of its own subtracting the value of the uplink
attenuation, if not, waits for the next allocated time slot; if yes, transmits an
uplink ONU serial number to start registration. The uplink signal is amplified by
the SOA, attenuated by the VOA, and then filtered by the filter to remove ASE noises.
The receiver receives the filtered signal, measures the light power of the same, and
converts the optical signal into an electrical signal to be transmitted to the MAC.
The OLT records the SOA gain value, the VOA attenuation value, and the ONU ID at this
time, completes the registration, and establishes a relationship between the ONU ID,
the SOA gain and the VOA attenuation. The flowchart is shown in Fig. 10.
[0056] The established form of the ONU ID, the SOA gain, and the VOA attenuation is shown
in Table 5.
Table 5
| ONU-ID |
SOA gain [dB] |
VOA attenuation [dB] |
SOA actual gain [dB] |
| 1 |
G1 |
A1 |
G1-A1 |
| 2 |
G2 |
A2 |
G2-A2 |
| 3 |
G1 |
A1 |
G1-A1 |
| 4 |
G2 |
A2 |
G2-A2 |
| 5 |
G2 |
A2 |
G2-A2 |
| ... |
... |
... |
... |
| n |
Gn |
An |
Gn-An |
[0057] A second registration method: the OLT assigns a minimum actual gain, for example,
5dB, to the SOA through the DBA-based output power control module. This actual gain
may be obtained from an SOA gain of 10dB and a VOA attenuation of 5dB. The OLT then
allocates the registration time slot and transmits a downlink registration signal
including a current SOA actual gain value (Equation 2). After receiving the registration
signal, the ONU determines whether it is in the registration time slot with the minimum
SOA actual gain, if yes, transmits uplink serial number information; if no, waits
for the registration time slot with the minimum SOA actual gain. The uplink optical
signal is amplified by the SOA, attenuated by the VOA, and filtered by the ASE filter
before being received by the OLT receiver. If the OLT receives correctly, the current
ONU ID, SOA gain value, and VOA attenuation value are recorded to establish a relationship
between the ONU ID, the SOA gain, and the VOA attenuation; if the OLT fails to receive
correctly, the OLT increases the SOA actual gain by a fixed value, for example, 5dB,
for example, by increasing the SOA gain to 13dB and decreasing the VOA attenuation
to 3dB, and then the above steps are repeated. After the SOA actual gain is increased
to a certain value, the OLT may correctly receive the ONU uplink signals. At this
time, the ONU ID, the SOA gain, and the VOA attenuation are recorded to establish
a relationship between the ONU ID, the SOA gain, and the VOA attenuation, and then
the registration is completed. The flowchart is shown in Fig. 11.
[0058] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the SOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID, the SOA gain,
and the VOA attenuation obtained from the registration process, as shown in Fig. 6,
so as to adjust the SOA gain value and the VOA attenuation value dynamically by the
DBA-based output power control module so that each of the ONUs tends to have the same
burst optical signal power.
Table 6
| ONU-ID |
Time point of arriving at OLT |
Burst duration |
SOA gain [dB] |
VOA attenuation [dB] |
| 1 |
t1 |
a |
G1 |
A1 |
| 2 |
t2 |
b |
G2 |
A2 |
| 3 |
t3 |
c |
G1 |
A1 |
| 4 |
t4 |
d |
G2 |
A2 |
| 5 |
t5 |
e |
G2 |
A2 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
Gn |
An |
[0059] Optionally, during the registration stage, the OLT may fine-tune the SOA gain and
the VOA attenuation according to the received ONU light power so that the uplink light
power reaches an optimal receiving power of the OLT receiver, for example, -18 dBm,
after being amplified by the SOA and attenuated by the VOA. Then, the ONU ID, the
SOA gain, and the VOA attenuation at this time are recorded so that each ONU has a
one-to-one SOA gain and VOA attenuation. In this way, the uplink optical signals of
each ONU may be amplified to the same optimal receiving power of the OLT.
Optional Embodiment IV
[0060] In this embodiment, a multi-channel amplification architecture and a method for equalizing
amplification output powers of each channel based on the architecture, and an OLT
for the same are provided. This optional embodiment solves not only the problem of
power equalization of each channel, but also the problem of different powers of different
channels entering the SOA and an unchangeable SOA gain due to a shared SOA of different
channels.
[0061] As shown in Fig. 12, an uplink signal line is amplified by an SOA for the first time,
and then divided into four signals with different wavelengths through WDM (Wavelength
Division Multiplex). Each of the signals is amplified by the SOA again, filtered by
a filter to remove ASE noises, attenuated by a variable optical attenuator (VOA),
and finally enters the receiver with a proper power. A power control module adjusts
the SOA gain or the VOA attenuation, or both, through dynamic bandwidth allocation
(DBA) so that different ONU burst packets of each channel of signals, after amplified,
enter the receiver with a power in a working range of the receiver. The specific process
is divided into two steps:
[0062] In a first step, a correspondence relationship between each ONU ID and a corresponding
channel of SOA gains (VOA attenuations) is established.
[0063] In a second step, after each channel of signals are divided through WDM, the SOA
gains (VOA attenuations) are adjusted in real time according to DBA so that light
powers incident on the receiver are within the working range of the receiver.
[0064] It should be noted that this embodiment may be implemented in a similar manner to
the above Optional Embodiments I, II and III, except that this embodiment may include
a plurality of SOAs or VOAs, and specifically, the relationship between each channel
of ONU IDs and the corresponding channel of SOA gains is established in the registration
stage, multiple channels of SOA gains (VOA attenuation) are adjusted.
[0065] This optional embodiment will be exemplified below with reference to specific examples.
Example 1
[0066] Fig. 13 is a schematic structural diagram of each channel of SOA gains after dynamically
adjusting WDM according to DBA. This architecture includes two steps. In a first step,
a relationship between each channel of ONU IDs and a corresponding channel of SOA
gains is established in the registration stage. In a second step, a dynamic gain adjustment
table is established with reference to DBA and according to the obtained relationship,
wherein a DBA-based output power control module dynamically adjusts the SOA gains
according to the table so that powers of the optical signals emitted by each ONU are
amplified, and the amplified light powers tend to fall into the working range of the
receiver.
[0067] In the first step, a relationship between each channel of ONU IDs and the corresponding
channel of SOA gains is established.
[0068] Since power values of each channel of ONU uplink optical signals that reach the SOA
is unknown at the beginning, a suitable SOA gain for each ONU uplink optical signal
cannot be determined. In PON standards, a dynamic range of the ODN may be up to 15
dB, and a fluctuation range of the light transmitting power of the ONU may be up to
5 dB. As a result, a difference in the light powers reaching the OLT receiver may
be up to 20 dB. If the SOA gain is set too small, some ONUs with greater signal attenuations
to the OLT cannot be registered. However, if the SOA gain is set too large, some ONUs
with smaller signal attenuations to the OLT may have excessively amplified light powers,
thereby damaging the OLT optical receiver.
[0069] Therefore, a suitable method is needed to enable the OLT to correctly receive uplink
burst information from the ONU with an appropriate gain, record the ONU ID and the
SOA gain value at that time, and establish a relationship between the two. Two ONU
registration methods are provided below.
[0070] A first ONU registration method: the OLT allocates registration time slots in segments
for each channel of signals. In each time slot, the SOA for each channel has a pre-assigned
gain that is set according to a power range that may be incident on the SOA and a
receiving light power range of the OLT receiver. For example, provided that a system
dynamic range is 20 dB, an incident light power range on SOA is [-40 dBm, -20 dBm],
and a receiving power range of the OLT receiver is [-28 dBm, -8 dBm], then two registration
time slots may be allocated in segments, and each of the two registration time slots
correspond to the pre-assigned SOA gain values of 10dB and 15dB, respectively. In
this way, the ONU corresponding to the incident power on SOA of [-40dBm, -30dBm] may
be registered in the time slot with an SOA gain of 15dB, and the ONU corresponding
to the incident power on SOA of [- 30dBm, - 20dBm] may be registered in the time slot
with an SOA gain of 10dB.
[0071] In a certain registration time slot, the OLT allocates a gain to the SOA through
the DBA-based output power control module and transmits a downlink signal which includes
downlink transmitting power information of an OLT, and notifies an eligible ONU to
transmit an uplink signal.
[0072] The eligible ONU refers to an ONU in which a value obtained by the ONU transmitting
power subtracting uplink attenuation, that is, the incident power value on SOA, falls
into a power range specified by the time slot.
[0073] The ONU obtains the light transmitting power of the OLT through the downlink signal
and calculates the uplink attenuation according to the received downlink optical signal
power. The uplink attenuation is obtained by the light transmitting power of the OLT
subtracting a downlink optical signal power value received by the ONU. Then, the ONU
determines whether the uplink light power to the SOA meets the power requirement of
the allocated time slot based on a value obtained by a light transmitting power of
a transmitter of its own subtracting the value of the uplink attenuation, if not,
waits for the next allocated time slot; if yes, transmits an uplink ONU serial number
to start registration. The uplink signal is amplified by the SOA with the pre-assigned
gain and then filtered by the filter to remove ASE noises. The receiver receives the
filtered signal and measures the light power of the same. The OLT records the gain
value of the SOA and the ONU ID at this time, completes the registration, and establishes
a relationship between the ONU ID and the SOA gain. The registration process may be
performed in four channels at the same time. The flowchart for one channel is shown
in Fig. 4.
[0074] The established relationship between the ONU ID and the SOA gain is shown in Table
7.
Table 7
| λ0ONU-ID |
Gain [dB] |
| 1 |
G1 |
| 2 |
G2 |
| ... |
... |
| n |
Gn |
| λ1ONU-ID |
Gain [dB] |
| 1 |
G2 |
| 2 |
G1 |
| ... |
... |
| n |
Gn |
| λ2ONU-ID |
Gain [dB] |
| 1 |
G3 |
| 2 |
G4 |
| ... |
... |
| n |
Gn |
| λ3ONU-ID |
Gain [dB] |
| 1 |
G4 |
| 2 |
G3 |
| ... |
... |
| n |
Gn |
[0075] A second registration method: the OLT assigns a minimum gain, for example, 5dB, to
the SOA through the DBA-based output power control module, and then allocates the
registration time slot and transmits a downlink registration signal including a current
SOA gain value.
[0076] After receiving the registration signal, the ONU determines whether it is in the
registration time slot with the minimum SOA gain, if yes, transmits uplink serial
number information; if no, waits for the registration time slot with the minimum SOA
gain.
[0077] The uplink optical signal is amplified by the SOA, and filtered by the ASE filter
before being received by the OLT receiver. If the OLT receives correctly, the current
ONU ID and SOA gain value are recorded to establish a relationship between the ONU
ID and the SOA gain; if the OLT fails to receive correctly, the OLT increases the
SOA gain by a fixed value, for example, 5dB, and the above steps are repeated. After
the SOA gain is increased to a certain value, the OLT may correctly receive the ONU
uplink signals. At this time, the ONU ID and the SOA gain are recorded to establish
a relationship between the ONU ID and the SOA gain, and then the registration is completed.
The registration in four channels may be performed at the same time. The flowchart
for one channel is shown in Fig. 5.
[0078] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the SOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID and the SOA gain
obtained from the registration process, as shown in Table 8, so as to adjust SOA gain
values of each channel dynamically by the DBA-based output power control module so
that each of the ONUs tends to have a burst optical signal power within the working
range of the receiver.
Table 8
| λ0 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Gain (dB) |
| 1 |
t1 |
a |
G1 |
| 2 |
t2 |
b |
G2 |
| ... |
... |
... |
... |
| n |
tn |
n |
Gn |
| λ1 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Gain (dB) |
| 1 |
t1 |
a |
G2 |
| 2 |
t2 |
b |
G1 |
| ... |
... |
... |
... |
| n |
tn |
n |
Gn |
| λ2 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Gain (dB) |
| 1 |
t1 |
a |
G3 |
| 2 |
t2 |
b |
G4 |
| ... |
... |
... |
... |
| n |
tn |
n |
Gn |
| λ3 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Gain (dB) |
| 1 |
t1 |
a |
G4 |
| 2 |
t2 |
b |
G3 |
| ... |
... |
... |
... |
| n |
tn |
n |
Gn |
[0079] Optionally, during the registration stage, the OLT may fine-tune the SOA gain according
to the received ONU light power so that the uplink light power reaches an optimal
receiving power of the OLT receiver, for example, -18 dBm, after being amplified by
the SOA. Then, the ONU ID and the SOA gain at this time are recorded so that each
ONU has a one-to-one SOA gain. In this way, the uplink optical signals of each ONU
may be amplified to the same optimal receiving power of the OLT.
Example 2
[0080] This example is similar to the above Example 1 except that the receiving power of
the OLT receiver is adjusted by adjusting attenuation. As shown in Fig. 14, in this
architecture, SOA actual gain for each channel = SOA fixed gain for each channel -
VOA attenuation for each channel (Equation 1)
[0081] The DBA-based output power control module may consist of a memory, a controller and
a driver for adjusting VOA attenuation.
[0082] In a first step, a relationship between the ONU ID and the VOA attenuation is established.
[0083] A first ONU registration method: the SOA is operated at a fixed gain, and the OLT
allocates registration time slots in segments. In each time slot, the VOA has a pre-assigned
attenuation that is set according to a power range that may be incident on the SOA
and a receiving light power range of the OLT receiver.
[0084] For example, provided that a system dynamic range is 20 dB, the SOA is operated at
a fixed gain of 20dB, an incident light power range on SOA is [-40 dBm, -20 dBm],
and a receiving power range of the OLT receiver is [-28 dBm, -8 dBm], then two registration
time slots may be allocated in segments, and each of the two registration time slots
correspond to the pre-assigned VOA attenuation values 10dB and 5dB, respectively.
In this way, the ONU corresponding to the incident power on SOA of [-40dBm, -30dBm]
may be registered in the time slot with a VOA attenuation of 5dB, and the ONU corresponding
to the incident power on SOA of [- 30dBm, - 20dBm] may be registered in the time slot
with a VOA attenuation of 10dB.
[0085] In a certain registration time slot, the OLT allocates an attenuation to the VOA
through the DBA-based output power control module and transmits a downlink signal
which includes the transmitting power information of the OLT and notifies an eligible
ONU to transmit an uplink signal.
[0086] The eligible ONU refers to an ONU in which a value obtained by the ONU transmitting
power subtracting an uplink attenuation, that is, the incident power value on SOA,
falls into a power range specified by the time slot. With a known light transmitting
power of the OLT, the ONU calculates the uplink attenuation according to the received
downlink optical signal power. The uplink attenuation is obtained by the light transmitting
power of the OLT subtracting a downlink optical signal power value received by the
ONU. Then, the ONU determines whether the uplink light power to the SOA meets the
power requirement of the allocated time slot based on a value obtained by a light
transmitting power of a transmitter of its own subtracting the value of the uplink
attenuation, if not, waits for the next allocated time slot; if yes, transmits an
uplink ONU serial number to start registration. The uplink signal is amplified by
the SOA with the fixed gain, filtered by the filter to remove ASE noises, and then
attenuated by the VOA. The receiver receives the signal, measures the light power
of the same, and converts the optical signal into an electrical signal to be transmitted
to the MAC. The OLT records the attenuation value of the VOA and the ONU ID at this
time, completes the registration, and establishes a relationship between the ONU ID
and the VOA attenuation. The registration processes in four channels may be performed
at the same time. The flowchart for one channel is shown in Fig. 8.
[0087] The established form of the ONU ID and the VOA attenuation is shown in Table 9.
Table 9
| λ0ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A1 |
Gλ0-A1 |
| 2 |
A2 |
Gλ0-A2 |
| ... |
... |
... |
| n |
An |
Gλ0-An |
| λ1 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A2 |
Gλ1-A2 |
| 2 |
A1 |
Gλ1-A1 |
| ... |
... |
... |
| n |
An |
Gλ1-An |
| λ2 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A3 |
Gλ2-A3 |
| 2 |
A4 |
Gλ2-A4 |
| ... |
... |
... |
| n |
An |
Gλ2-An |
| λ3 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A4 |
Gλ3-A4 |
| 2 |
A3 |
Gλ3-A3 |
| ... |
... |
... |
| n |
An |
Gλ3-An |
[0088] A second registration method: the OLT assigns a maximum attenuation, for example,
10dB, to the VOA through the DBA-based output power control module, and then allocates
the registration time slot and transmits a downlink registration signal including
a current SOA actual gain value (Equation 1).
[0089] After receiving the registration signal, the ONU determines whether it is in the
registration time slot with the minimum SOA actual gain, if yes, transmits uplink
serial number information; if no, waits for the registration time slot with the minimum
SOA actual gain.
[0090] The uplink optical signal is amplified by the SOA, filtered by the ASE filter and
attenuated by the VOA before being received by the OLT receiver. If the OLT receives
correctly, the current ONU ID and VOA attenuation value are recorded to establish
a relationship between the ONU ID and the VOA attenuation; if the OLT fails to receive
correctly, the OLT decreases the VOA attenuation by a fixed value, for example, 5dB,
and the above steps are repeated. After the VOA attenuation is decreased to a certain
value, the OLT may correctly receive the ONU uplink signals. At this time, the ONU
ID and the VOA attenuation are recorded to establish a relationship between the ONU
ID and the VOA attenuation, and then the registration is completed. The registration
in four channels may be performed at the same time. The flowchart for one channel
is shown in Fig. 9.
[0091] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the VOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID and the VOA attenuation
obtained from the registration process, as shown in Table 10, so as to adjust the
VOA attenuation value dynamically by the DBA-based output power control module so
that each of the ONUs tends to have the same burst optical signal power.
Table 10
| λ0 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A1 |
Gλ0-A1 |
| 2 |
t2 |
b |
A2 |
Gλ0-A2 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gλ0-An |
| λ1 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A2 |
Gλ1-A2 |
| 2 |
t2 |
b |
A1 |
Gλ1-A1 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gλ1-An |
| λ2 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A3 |
Gλ2-A3 |
| 2 |
t2 |
b |
A4 |
Gλ2-A4 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gλ2-An |
| λ3 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A4 |
Gλ3-A4 |
| 2 |
t2 |
b |
A3 |
Gλ3-A3 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gλ3-An |
[0092] Optionally, during the registration stage, the OLT may fine-tune the VOA attenuation
according to the received ONU light power so that the uplink light power reaches an
optimal receiving power of the OLT receiver, for example, -18 dBm, after being amplified
by the SOA and attenuated by the VOA. Then, the ONU ID and the VOA attenuation at
this time are recorded so that each ONU has a one-to-one VOA attenuation. In this
way, the uplink optical signals of each ONU may be amplified to the same optimal receiving
power of the OLT receiver.
Example 3
[0093] Example 3 is similar to Examples 1 and 2 except that the receiving power of the OLT
receiver is adjusted by adjusting both the SOA gain and the VOA attenuation. This
has the advantage of reducing requirements on the adjusting range of the SOA and the
VOA. In the architecture as shown in Fig. 14, SOA actual gain for each channel = SOA
gain for each channel - VOA attenuation for each channel (Equation 2).
[0094] The DBA-based output power control module may consist of a memory, a controller,
and a driver for adjusting an SOA gain and VOA attenuation.
[0095] In a first step, a relationship between the ONU ID, the SOA gain, and the VOA attenuation
is established.
[0096] A first ONU registration method: the OLT allocates registration time slots in segments.
In each time slot, the SOA is provided with a pre-assigned gain, the VOA is provided
with a pre-assigned attenuation, and a difference between the two is called an SOA
actual gain.
[0097] This pre-assigned actual gain is set according to a power range that may be incident
on the SOA and a receiving light power range of the OLT receiver. For example, provided
that a system dynamic range is 20 dB, an incident light power range on SOA is [-40
dBm, -20 dBm], and a receiving power range of the OLT receiver is [-28 dBm, -8 dBm],
then two registration time slots may be allocated in segments, and each of the two
registration time slots correspond to the pre-assigned SOA actual gain values 10dB
and 15dB, respectively. Accordingly, when the actual gain value is 10dB, the SOA gain
may be 15dB, and the VOA attenuation may be 5dB; when the actual gain value is 15dB,
the SOA gain may be 17dB, and the VOA attenuation may be 2dB. In this way, when the
SOA or the VOA alone is desired to be adjusted by a range of 5dB, adjusting both of
them may decrease the range to 2dB and 3dB.
[0098] The ONU corresponding to the incident power on SOA of [-40 dBm, -30 dBm] may be registered
in a time slot with an SOA actual gain of 5dB, and the ONU corresponding to the incident
power on SOA of [- 30dBm, - 20dBm] may be registered in the time slot with an SOA
actual gain of 10dB.
[0099] In a certain registration time slot, The OLT assigns a gain to the SOA, and attenuation
to the VOA through the DBA-based output power control module, and transmits a downlink
signal which includes the transmitting power information of the OLT and notifies an
eligible ONU to transmit an uplink signal.
[0100] The eligible ONU refers to an ONU in which a value obtained by the ONU transmitting
power subtracting uplink attenuation, that is, the incident power value on SOA, falls
into a power range specified by the time slot. With a known light transmitting power
of the OLT, the ONU calculates the uplink attenuation according to the received downlink
optical signal power. The uplink attenuation is obtained by the light transmitting
power of the OLT subtracting a downlink optical signal power value received by the
ONU. Then, the ONU determines whether the uplink light power to the SOA meets the
power requirement of the allocated time slot based on a value obtained by a light
transmitting power of a transmitter of its own subtracting the value of the uplink
attenuation, if not, waits for the next allocated time slot; if yes, transmits an
uplink ONU serial number to start registration. After the uplink signal is amplified
by the SOA, filtered by the filter to remove ASE noises, and then attenuated by the
VOA, the receiver receives the filtered signal, measures the light power of the same,
and converts the optical signal into an electrical signal to be transmitted to the
MAC. The OLT records the SOA gain value, the VOA attenuation value, and the ONU ID
at this time, completes the registration, and establishes a relationship between the
ONU ID, the SOA gain and the VOA attenuation. The registration in four channels may
be performed at the same time. The registration flowchart for one channel is shown
in Fig. 10.
[0101] The established form of the ONU ID, the SOA gain, and the VOA attenuation is shown
in Table 11.
Table 11
| λ0ONU-ID |
SOA gain [dB] |
VOA attenuation [dB] |
Actual gain [dB] |
| 1 |
G1 |
A1 |
G1-A1 |
| 2 |
G2 |
A2 |
G2-A2 |
| ... |
... |
... |
... |
| n |
Gn |
An |
Gn-An |
| λ1 ONU-ID |
SOA gain [dB] |
VOA attenuation [dB] |
Actual gain [dB] |
| 1 |
G2 |
A2 |
G2-A2 |
| 2 |
G1 |
A1 |
G1-A1 |
| ... |
... |
... |
... |
| n |
Gn |
An |
Gn-An |
| λ2 ONU-ID |
SOA gain [dB] |
VOA attenuation [dB] |
Actual gain [dB] |
| 1 |
G3 |
A3 |
G3-A3 |
| 2 |
G4 |
A4 |
G4-A4 |
| ... |
... |
... |
... |
| n |
Gn |
An |
Gn-An |
| λ3 ONU-ID |
SOA gain [dB] |
VOA attenuation [dB] |
Actual gain [dB] |
| 1 |
G4 |
A4 |
G4-A4 |
| 2 |
G3 |
A3 |
G3-A3 |
| ... |
... |
... |
... |
| n |
Gn |
An |
Gn-An |
[0102] A second registration method: the OLT assigns a minimum actual gain, for example,
5dB, to the SOA through the DBA-based output power control module. This actual gain
may be obtained from an SOA gain of 10dB and a VOA attenuation of 5dB. The OLT then
allocates the registration time slot and transmits a downlink registration signal
including a current SOA actual gain value (Equation 2). After receiving the registration
signal, the ONU determines whether it is in the registration time slot with the minimum
SOA actual gain if yes, transmits uplink serial number information; if no, waits for
the registration time slot with the minimum SOA actual gain.
[0103] The uplink optical signal is amplified by the SOA, filtered by the ASE filter and
attenuated by the VOA before being received by the OLT receiver. If the OLT receives
correctly, the current ONU ID, SOA gain value, and VOA attenuation value are recorded
to establish a relationship between the ONU ID, the SOA gain, and the VOA attenuation;
if the OLT fails to receive correctly, the OLT increases the SOA actual gain by a
fixed value, for example, 5dB, for example, by increasing the SOA gain to 13dB and
decreasing the VOA attenuation to 3dB, and then the above steps are repeated.
[0104] After the SOA actual gain is increased to a certain value, the OLT may correctly
receive the ONU uplink signals. At this time, the ONU ID, the SOA gain, and the VOA
attenuation are recorded to establish a relationship between the ONU ID, the SOA gain,
and the VOA attenuation, and then the registration is completed. The flowchart is
shown in Fig. 11.
[0105] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the SOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID, the SOA gain,
and the VOA attenuation obtained from the registration process, as shown in Table
12, so as to adjust the SOA gain value and the VOA attenuation value dynamically by
the DBA-based output power control module so that each of the ONUs tends to have the
same burst optical signal power.
Table 12
| λ0 ONU-ID |
Time point of arriving at OLT |
Burst duration |
SOA gain (dB) |
VOA attenuation (dB) |
Actual gain (dB) |
| 1 |
t1 |
a |
G1 |
A1 |
G1-A1 |
| 2 |
t2 |
b |
G2 |
A2 |
G2-A2 |
| ... |
... |
... |
... |
... |
... |
| n |
tn |
n |
Gn |
An |
Gn-An |
| λ1 ONU-ID |
Time point of arriving at OLT |
Burst duration |
SOA gain (dB) |
VOA attenuation (dB) |
Actual gain (dB) |
| 1 |
t1 |
a |
G2 |
A2 |
G2-A2 |
| 2 |
t2 |
b |
G1 |
A1 |
G1-A1 |
| ... |
... |
... |
... |
... |
... |
| n |
tn |
n |
Gn |
An |
Gn-An |
| λ2 ONU-ID |
Time point of arriving at OLT |
Burst duration |
SOA gain (dB) |
VOA attenuation (dB) |
Actual gain (dB) |
| 1 |
t1 |
a |
G3 |
A3 |
G3-A3 |
| 2 |
t2 |
b |
G4 |
A4 |
G4-A4 |
| ... |
... |
... |
... |
... |
... |
| n |
tn |
n |
Gn |
An |
Gn-An |
| λ3 ONU-ID |
Time point of arriving at OLT |
Burst duration |
SOA gain (dB) |
VOA attenuation (dB) |
Actual gain (dB) |
| 1 |
t1 |
a |
G4 |
A4 |
G4-A4 |
| 2 |
t2 |
b |
G3 |
A3 |
G3-A3 |
| ... |
... |
... |
... |
... |
... |
| n |
tn |
n |
Gn |
An |
Gn-An |
[0106] Optionally, during the registration stage, the OLT may fine-tune the SOA gain and
the VOA attenuation according to the received ONU light power so that the uplink light
power reaches an optimal receiving power of the OLT receiver, for example, -18 dBm,
after being amplified by the SOA and attenuated by the VOA. Then, the ONU ID, the
SOA gain, and the VOA attenuation at this time are recorded so that each ONU has a
one-to-one SOA gain and VOA attenuation. In this way, the uplink optical signals of
each ONU may be amplified to the same optimal receiving power of the OLT receiver.
Example 4
[0107] This example is similar to Example 2 except that each channel of uplink signals are
amplified by a shared SOA, and attenuated by the VOA after WDM (Wavelength Division
Multiplexing) and filtering so that the attenuated signal light power falls into a
receiving range of the receiver. As shown in Fig. 15, a decreased number of SOAs are
used in this example. SOA actual gain for each channel = shared SOA fixed gain - VOA
attenuation for each channel (Equation 3).
[0108] The DBA-based output power control module may consist of a memory, a controller and
a driver for adjusting VOA attenuation.
[0109] In a first step, a relationship between the ONU ID and the VOA attenuation is established.
[0110] In a first ONU registration method, the shared SOA is operated at a fixed gain, and
the OLT allocates registration time slots in segments for each channel. In each time
slot, the VOA has a pre-assigned attenuation that is set according to a power range
that may be incident on the SOA and a receiving light power range of the OLT receiver.
[0111] For example, for a single channel, provided that a system dynamic range is 20 dB,
the shared SOA is operated at a fixed gain of 20dB, an incident light power range
on SOA is [-40 dBm, -20 dBm], and a receiving power range of the OLT receiver is [-28
dBm, -8 dBm], then two registration time slots may be allocated in segments, and each
of the two registration time slots correspond to the pre-assigned VOA attenuation
values 10dB and 5dB, respectively. In this way, the ONU corresponding to the incident
power on SOA of [-40dBm, -30dBm] may be registered in the time slot with a VOA attenuation
of 5dB, and the ONU corresponding to the incident power on SOA of [- 30dBm, - 20dBm]
may be registered in the time slot with a VOA attenuation of 10dB. When the light
powers incident on the SOA from different channels are inconsistent, the SOA may have
a fixed gain since the VOA may be adjusted independently for each channel.
[0112] In a certain registration time slot, the OLT allocates attenuation to the VOA through
the DBA-based output power control module and transmits a downlink signal which includes
the transmitting power information of the OLT and notifies an eligible ONU to transmit
an uplink signal.
[0113] The eligible ONU refers to an ONU in which a value obtained by the ONU transmitting
power subtracting uplink attenuation, that is, the incident power value on SOA, falls
into a power range specified by the time slot. With a known light transmitting power
of the OLT, the ONU calculates the uplink attenuation according to the received downlink
optical signal power. The uplink attenuation is obtained by the light transmitting
power of the OLT subtracting a downlink optical signal power value received by the
ONU. Then, the ONU determines whether the uplink light power to the SOA meets the
power requirement of the allocated time slot based on a value obtained by a light
transmitting power of a transmitter of its own subtracting the value of the uplink
attenuation, if not, waits for the next allocated time slot; if yes, transmits an
uplink ONU serial number to start registration. The uplink signal is amplified by
the SOA with the fixed gain, filtered by the filter to remove ASE noises, and then
attenuated by the VOA. The receiver receives the signal, measures the light power
of the same, and converts the optical signal into an electrical signal to be transmitted
to the MAC. The OLT records the attenuation value of the VOA and the ONU ID at this
time, completes the registration, and establishes a relationship between the ONU ID
and the VOA attenuation. The registration processes in four channels may be performed
at the same time. The flowchart for one channel is shown in Fig. 8. The established
form of the ONU ID and the VOA attenuation is shown in Table 13.
Table 13
| λ0ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A1 |
Gshare-A1 |
| 2 |
A2 |
Gshare -A2 |
| ... |
... |
... |
| n |
An |
Gshare -An |
| λ1 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A2 |
Gshare -A2 |
| 2 |
A1 |
Gshare -A1 |
| ... |
... |
... |
| n |
An |
Gshare -An |
| λ2 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A3 |
Gshare -A3 |
| 2 |
A4 |
Gshare -A4 |
| ... |
... |
... |
| n |
An |
Gshare -An |
| λ3 ONU-ID |
Attenuation [dB] |
Actual gain [dB] |
| 1 |
A4 |
Gshare -A4 |
| 2 |
A3 |
Gshare -A3 |
| ... |
... |
... |
| n |
An |
Gshare -An |
[0114] A second registration method: the OLT assigns a maximum attenuation, for example,
10dB, to the VOA through the DBA-based output power control module. The OLT then allocates
the registration time slot and transmits a downlink registration signal including
a current SOA actual gain value (Equation 3).
[0115] After receiving the registration signal, the ONU determines whether it is in the
registration time slot with the minimum SOA actual gain if yes, transmits uplink serial
number information; if no, waits for the registration time slot with the minimum SOA
actual gain.
[0116] The uplink optical signal is amplified by the SOA, filtered by the ASE filter and
attenuated by the VOA before being received by the OLT receiver. If the OLT receives
correctly, the current ONU ID and VOA attenuation value are recorded to establish
a relationship between the ONU ID and the VOA attenuation; if the OLT fails to receive
correctly, the OLT decreases the VOA attenuation by a fixed value, for example, 5dB,
and the above steps are repeated. After the VOA attenuation is decreased to a certain
value, the OLT may correctly receive the ONU uplink signals. At this time, the ONU
ID and the VOA attenuation are recorded to establish a relationship between the ONU
ID and the VOA attenuation, and then the registration is completed. The registration
in four channels may be performed at the same time. The flowchart for one channel
is shown in Fig. 9.
[0117] In a second step, the OLT calculates a time point when each of the ONU optical signal
reaches the VOA according to the DBA and the link delay, and establishes a dynamic
gain adjustment table based on the relationship between the ONU ID and the VOA attenuation
obtained from the registration process, as shown in Table 14, so as to adjust the
VOA attenuation value dynamically by the DBA-based output power control module so
that each of the ONUs tends to have the same burst optical signal power.
Table 14
| λ0 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A1 |
Gshare-A1 |
| 2 |
t2 |
b |
A2 |
Gshare -A2 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gshare -An |
| λ1 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A2 |
Gshare -A2 |
| 2 |
t2 |
b |
A1 |
Gshare -A1 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gshare -An |
| λ2 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A3 |
Gshare -A3 |
| 2 |
t2 |
b |
A4 |
Gshare -A4 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gshare -An |
| λ3 ONU-ID |
Time point of arriving at OLT |
Burst duration |
Attenuation (dB) |
Actual gain [dB] |
| 1 |
t1 |
a |
A4 |
Gshare -A4 |
| 2 |
t2 |
b |
A3 |
Gshare -A3 |
| ... |
... |
... |
... |
... |
| n |
tn |
n |
An |
Gshare -An |
[0118] Optionally, during the registration stage, the OLT may fine-tune the VOA attenuation
according to the received ONU light power so that the uplink light power reaches an
optimal receiving power of the OLT receiver, for example, -18 dBm, after being amplified
by the SOA and attenuated by the VOA. Then, the ONU ID and the VOA attenuation at
this time are recorded so that each ONU has a one-to-one VOA attenuation. In this
way, the uplink optical signals of each ONU may be amplified to the same optimal receiving
power of the OLT.
Example 5
[0119] In this example, as shown in Fig. 16, signals of four channels are each firstly amplified
by one SOA, and then further amplified by the SOA again, filtered and attenuated before
received by the receiver. The power control module controls the SOA gain and the VOA
attenuation for each channel based on DBA so that the receiving light power of the
receiver is within the working range of the receiver. This example is similar to Example
3 except that the uplink signal is firstly amplified by a shared SOA before being
divided through WDM, and then further amplified by the SOA and attenuated by the VOA
in each channel.
[0120] The entire system is shown in Fig. 17, in which the amplification of the uplink signal
may be flexibly selected according to the different embodiments described above.
[0121] Through the description of the above embodiment, those skilled in the art can clearly
understand that the method according to the above embodiment may be implemented by
means of software plus a necessary general hardware platform. Obviously, it may also
be implemented by hardware, but in most cases, the former is preferable. Based on
such understanding, the technical solutions of the present invention essentially or,
in other words, a part thereof contributing to the prior art, can be embodied in a
form of a software product, wherein the software product is stored in a storage medium
(such as an ROM/RAM, a disk, or an optical disc) and includes a number of instructions
to make a terminal device (which may be a mobile phone, a computer, a server, or a
network device, etc.) to execute the methods of the various embodiments of the present
disclosure.
Embodiment 2
[0122] In this embodiment, there is further provided an optical signal power control device
configured to implement the above embodiments and preferable implementations. Details
which have been explained will not be repeated here. As used herein, the term "module"
may be a combination of software and/or hardware that can realize a preset function.
Although the devices described in the following embodiment is preferably implemented
in software, hardware, or a combination of software and hardware, is also possible
and contemplated.
[0123] Fig. 18 is a structural block diagram of an optical signal power control device according
to an embodiment of the present disclosure. As shown in Fig. 18, the device includes:
- 1) an acquisition module 182 configured to acquire different time points when uplink
optical signals of optical network units (ONUs) arrive at an optical signal amplifier;
- 2) an establishment module 184 configured to establish a correspondence relationship
between an ONU ID and a power control factor of the uplink optical signals; and
- 3) a control module 186 configured to perform power control on the uplink optical
signals according to the different time points and the correspondence relationship.
[0124] In this embodiment, an application scenario of the foregoing optical signal amplification
device includes Passive Optical Network (PON). In this application scenario, by acquiring
different time points when uplink optical signals of optical network units (ONUs)
arrive at an optical signal amplifier or a variable optical attenuator; establishing
a correspondence relationship between an ONU ID and a power control factor of the
uplink optical signals; and performing power control on the uplink optical signals
according to the different time points and the correspondence relationship, the uplink
burst signals of the ONU are amplified to a range receivable by the OLT receiver,
thereby solving the problem of equalizing uplink burst signal amplification in an
optical network unit (ONU) in the related art, and achieving the technical effect
of reducing requirements on the receiving power range of the OLT receiver.
[0125] It should be noted that, in this embodiment, the number of optical signal amplifiers
includes but is limited to: one or more than one; and the number of variable optical
attenuators includes but is not limited to: one or more than one.
[0126] Optionally, in the embodiment, the optical signal amplifier is mainly described by
taking a semiconductor amplifier (SOA) as an example.
[0127] Optionally, the power control factor includes at least one of: a gain of the optical
signal amplifier, and an attenuation of the variable optical attenuator.
[0128] Fig. 19 is a structural block diagram (I) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 19, the establishment
module 184 includes:
- 1) a first allocation unit 192 configured to allocate a registration time slot and
transmit a downlink registration signal when the power control factor is a gain of
the optical signal amplifier; and
- 2) a first establishment unit 194 configured to start, when the ONU receives the downlink
registration signal and determines that a power requirement of the registration time
slot is met, registration and establishment of a correspondence relationship between
the ONU ID and the gain of the optical signal amplifier.
[0129] Fig. 20 is a structural block diagram (II) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 20, the establishment
module 184 includes:
- 1) a second allocation unit 202 configured to allocate a registration time slot and
transmit a downlink registration signal when the power control factor is a gain of
the optical signal amplifier, wherein the downlink registration signal includes gain
information of the optical signal amplifier;
- 2) a first increment unit 204 configured to increase, when the ONU receives the downlink
registration signal and determines that the downlink registration signal is in a registration
time slot with a minimum gain of the optical signal amplifier, the gain of the optical
signal amplifier until a serial number transmitted by the ONU is correctly received.
- 3) a second establishment unit 206 configured to establish a correspondence relationship
between the ONU ID and the gain of the optical signal amplifier.
[0130] Fig. 21 is a structural block diagram (III) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 21, the establishment
module 184 includes:
- 1) a third allocation unit 212 configured to allocate a registration time slot and
transmit a downlink registration signal when the power control factor is an attenuation
of the variable optical attenuator, wherein the registration time slot is pre-assigned
an attenuation value.
- 2) a third establishment unit 214 configured to start, when the ONU receives the downlink
registration signal and determines a power requirement of the registration time slot
is met, registration and establishment of a correspondence relationship between the
ONU ID and the attenuation of the variable optical attenuator.
[0131] Fig. 22 is a structural block diagram (IV) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 22, the establishment
module 184 includes:
- 1) a first setting unit 222 configured to set, when the power control factor is an
attenuation of the variable optical attenuator, the attenuation of the variable optical
attenuator to maximum;
- 2) a fourth allocation unit 224 configured to allocate a registration time slot and
transmit a downlink registration signal, wherein the downlink registration signal
includes attenuation information of the variable optical attenuator.
- 3) a decrement unit 226 configured to decrease, when the ONU receives the downlink
registration signal and determines the downlink registration signal is in a registration
time slot with a minimum actual gain of the optical signal amplifier, the attenuation
of the variable optical attenuator until a serial number transmitted by the ONU is
correctly received; and
- 4) a fourth establishment unit 228 configured to establish a relationship between
the ONU ID and the attenuation of the variable optical attenuator.
[0132] Fig. 23 is a structural block diagram (V) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 23, the establishment
module 184 includes:
- 1) a fifth allocation unit 232 configured to allocate a registration time slot and
transmit a downlink registration signal when the power control factor is a gain of
the optical signal amplifier and an attenuation of the variable optical attenuator,
wherein in the registration time slot, the optical signal amplifier is provided with
a pre-assigned gain, and the variable optical attenuator is provided with a pre-assigned
attenuation.
- 2) a fifth establishment unit 234 configured to start, when the ONU receives the downlink
registration signal and determines a power requirement of the registration time slot
is met, registration and establishment of a correspondence relationship between the
ONU ID, the gain of the optical signal amplifier, and the attenuation of the variable
optical attenuator.
[0133] Fig. 24 is a structural block diagram (VI) of an optical signal power control device
according to an embodiment of the present disclosure. As shown in Fig. 24, the establishment
module 184 includes:
- 1) a second setting unit 242 configured to set an actual gain of the optical signal
amplifier to minimum when the power control factor is a gain of the optical signal
amplifier and an attenuation of the variable optical attenuator;
- 2) a sixth allocation unit 244 configured to allocate a registration time slot and
transmit a downlink registration signal, wherein the downlink registration signal
includes actual gain information of the optical signal amplifier.
- 3) a second increment unit 246 configured to increase, when the ONU receives the downlink
registration signal and determines the downlink registration signal is in a registration
time slot with a minimum actual gain of the optical signal amplifier, the gain of
the optical signal amplifier until a serial number transmitted by the ONU is correctly
received; and
- 4) a sixth establishment unit 248 configured to establish a correspondence relationship
between the ONU ID, the gain of the optical signal amplifier, and the attenuation
of the variable optical attenuator.
[0134] Optionally, a plurality of optical signal amplifiers or variable optical attenuators
are provided. When a plurality of optical signal amplifiers or variable optical attenuators
are provided, a plurality of correspondence relationships are provided, wherein each
of the plurality of correspondence relationships is a relationship between each channel
of ONU IDs and a power control factor of the corresponding uplink optical signals.
[0135] Optionally, before reaching the plurality of optical signal amplifiers and/or variable
optical attenuators, the uplink optical signals are subjected to corresponding power
control via a shared optical signal amplifier.
[0136] It should be noted that each of the above modules may be implemented by software
or hardware. For the latter, it may be implemented by, but are not limited to: the
above modules all located in the same processor; or, the above modules each located
in different processors in any combination.
Embodiment 3
[0137] In an embodiment of the present disclosure, there is also provided an optical line
terminal (OLT), including the device according to Embodiment 2.
Embodiment 4
[0138] In an embodiment of the present disclosure, there is also provided a storage medium.
Optionally, in the present embodiment, the storage medium may be configured to store
a program code for performing the following steps S1 to S3:
At step S1, acquiring different time points when uplink optical signals of optical
network units (ONUs) arrive at an optical signal amplifier or a variable optical attenuator;
At step S2, establishing a correspondence relationship between an ONU ID and a power
control factor of the uplink optical signals.
At step S3, performing power control on the uplink optical signals according to the
different time points and the correspondence relationship.
[0139] Optionally, in the present embodiment, the storage medium may include, but is not
limited to: a U Disk, a read only memory (ROM), a random access memory (RAM), a mobile
hard disk, a disk or optical disk, and other medium that can store a program code.
[0140] Optionally, in the present embodiment, the processor executes the above steps S1
to S3 according to the stored program code in the storage medium.
[0141] Optionally, specific examples in this embodiment may refer to the examples described
in the foregoing embodiments and optional implementations, which will not be repeated
herein.
[0142] In an embodiment of the present disclosure, there is further provided an electronic
device, including a memory storing a computer program thereon, and a processor configured
to execute the computer program to perform steps of any of the method embodiments
as described above.
[0143] Optionally, the electronic device may further include a transmission device, and
an input and output device, wherein the transmission device is coupled to the processor,
and the input and output device is coupled to the processor.
[0144] Obviously, a person skilled in the art would understand that the above modules and
steps of the present disclosure can be realized by using a universal computing device,
can be integrated in a single computing device or distributed on a network that consists
of a plurality of computing devices; and alternatively, they can be realized by using
the executable program code of the computing device, so that they can be stored in
a storage device and executed by the computing device, in some cases, can perform
the steps shown or described in a sequence other than herein, or they are made into
various integrated circuit modules respectively, or a plurality of modules or steps
thereof are made into a single integrated circuit module, thus to be realized. In
this way, the present disclosure is not restricted to any particular hardware and
software combination.
[0145] The descriptions above are only optional embodiments of the present disclosure, which
are not used to restrict the present disclosure.