Patent ID: 8116637
Filing Date: 2012-02-14
Classification: H04B

Abstract:
1. An optical transmitter to output signal light, comprising: a laser diode for emitting modulated light; an optical filter with a transmission spectrum showing a plurality of transmission maxima and a reflection spectrum showing a plurality of reflection minima corresponding to said transmission maxima, said optical filter transmitting a portion of said modulated light and reflecting another portion of said modulated light; a first photodiode for detecting a portion of said modulated light; a second photodiode for detecting a portion of said another portion of said modulated light reflected by said optical filter; an automatic temperature control circuit to set a temperature of said laser diode in a target temperature; and a controller configured to lower said target temperature referred in said automatic temperature control circuit when an output of said first photodiode is in phase with respect to an output of said second photodiode until said output of said first photodiode is out of phase with respect to said output of said second photodiode.