(19)
(11) EP 1 624 543 A8

(12) CORRECTED EUROPEAN PATENT APPLICATION
published in accordance with Art. 158(3) EPC

(15) Correction information:
Corrected version no 1 (W1 A1)

(48) Corrigendum issued on:
22.11.2006 Bulletin 2006/47

(43) Date of publication:
08.02.2006 Bulletin 2006/06

(21) Application number: 04732770.5

(22) Date of filing: 13.05.2004
(51) International Patent Classification (IPC): 
H01S 5/068(2006.01)
(86) International application number:
PCT/JP2004/006767
(87) International publication number:
WO 2004/102754 (25.11.2004 Gazette 2004/48)
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 13.05.2003 JP 2003135168

(71) Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Tokyo 100-8116 (JP)

(72) Inventors:
  • KAWAI, Shingo, c/o NTT Intellectual Property Ctr.
    Musashino-shi, Tokyo 180-8585 (JP)
  • KAWADA, Hideo, c/o NTT Intellectual Property Ctr.
    Musashino-shi, Tokyo 180-8585 (JP)
  • YOSHIMOTO, Naoto, NTT Intellectual Property Ctr.
    Musashino-shi, Tokyo 180-8585 (JP)
  • OGAWA, Toru, c/o NTT Intellectual Property Center
    Musashino-shi, Tokyo 180-8585 (JP)
  • IWATSUKI, Katsumi, NTT Intellectual Property Ctr.
    Musashino-shi, Tokyo 180-8585 (JP)

(74) Representative: Beresford, Keith Denis Lewis et al
BERESFORD & Co. 16 High Holborn
London WC1V 6BX
London WC1V 6BX (GB)


(56) References cited: : 
   
       


    (54) OPTICAL MODULE AND ITS WAVELENGTH MONITOR CONTROL METHOD


    (57) The present invention provides wavelength monitoring and/or control enabling size reduction and low power operation without requiring a complicated optical system in its wavelength monitoring and controlling mechanism.
    The measurement portion (1) measures temperature by a thermistor (5) in the measurement portion, and measures a bias current by using an LD drive current detecting circuit (6). The LD temperature, optical output and bias current are measured by the measurement portion. The relationship between the LD temperature and wavelengths or between the temperature, bias current and wavelengths is stored in a memory map of the storage portion (2). The central controlling portion (3) calculates wavelengths on the basis of the temperature and the bias current or the temperature information of the measurement portion, and the relationship between the LD temperature, bias current and wavelengths or between the temperature and wavelengths of the storage portion.