| (19) |
 |
|
(11) |
EP 1 806 557 A8 |
| (12) |
CORRECTED EUROPEAN PATENT APPLICATION |
|
Note: Bibliography reflects the latest situation |
| (15) |
Correction information: |
|
Corrected version no 1 (W1 A2) |
| (48) |
Corrigendum issued on: |
|
09.06.2010 Bulletin 2010/23 |
| (88) |
Date of publication A3: |
|
31.03.2010 Bulletin 2010/13 |
| (43) |
Date of publication: |
|
11.07.2007 Bulletin 2007/28 |
| (22) |
Date of filing: 25.01.2002 |
|
| (51) |
International Patent Classification (IPC):
|
|
| (84) |
Designated Contracting States: |
|
DE FR GB |
| (30) |
Priority: |
26.01.2001 JP 2001017943
|
| (62) |
Application number of the earlier application in accordance with Art. 76 EPC: |
|
02250526.7 / 1227297 |
| (71) |
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION |
|
Tokyo, 100-8116 (JP) |
|
| (72) |
Inventors: |
|
- Goh, Takashi
NTT Intellectual Property Center
Musashino-shi
Tokyo 180-8585 (JP)
- Abe, Makoto
NTT Intellectual Property Center
Musashino-shi
Tokyo 180-8585 (JP)
- Inoue, Yasuyuki
NTT Intellectual Property Center
Musashino-shi
Tokyo 180-8585 (JP)
- Okuno, Masayuki
NTT Intellectual Property Center
Musashino-shi
Tokyo 180-8585 (JP)
- Saida, Takashi
NTT Intellectual Property Center
Musashino-shi
Tokyo 180-8585 (JP)
|
| (74) |
Representative: Roberts, Gwilym Vaughan et al |
|
Kilburn & Strode LLP
20 Red Lion Street
London WC1R 4PJ
London WC1R 4PJ (GB) |
|
| |
|
|
|
Remarks: |
|
This application was filed on 21 - 02 - 2007 as a divisional application to the application
mentioned under INID code 62. |
|
| (54) |
Interferometer and its fabrication method |
(57) An interferometer includes a waveguide core (2), and thin film heaters (4a, 4b) with
widths W1 and W2. The thin film heaters are mounted directly above the waveguide core,
and operate as two types of different annealing regions. The annealing, which is carried
out by supplying current to the thin film heaters (4a,4b), can alter the quality of
the cladding (3), and change the stress applied on the waveguide core (2), thereby
making it possible to control the polarization dependency. Thus changing the width
of the thin film heaters (4a, 4b) and/or the amount of the supply current thereto
enables the permanent control of the effective refractive index (birefringence index)
independently in the transverse electric polarization mode and the transverse magnetic
polarization mode. This enables the transverse electric polarization mode to be adjusted
to a phase difference of λ/2, and the transverse magnetic polarization mode to a phase
difference of zero.