Patent ID: 6885684

Claim:
A method for controlling an output wavelength of a laser module to a target wavelength, the module comprising a laser diode for emitting light, a temperature regulator, a wavelength monitor for monitoring a wavelength of the light, a temperature control circuit for adjusting a temperature of the laser diode and a data processing unit connected to the temperature control circuit; the method comprising the steps of: a) transmitting a first data from the data processing unit to the temperature control circuit, the first data corresponding to a first temperature; b) controlling the temperature regulator in response to the first data so that the temperature of the laser diode becomes the first temperature; c) transmitting a second data from the data processing unit to the temperature control circuit after the temperature of the laser diode has been adjusted to the first temperature, the second data indicating a second temperature; d) controlling the temperature regulator in response to the second data so that the temperature of the laser diode becomes the second temperature; and e) feedback controlling the second temperature according to the output of the wavelength monitor so that the output wavelength of the laser module becomes the target wavelength.