Patent ID: 6154474
Filing Date: 2000-11-28
Classification: H01S

Abstract:
A laser diode optical wavelength control apparatus comprising:a laser diode;optical branching means for branching a laser beam emitted by said laser diode into first, second, and third branched laser beams;a narrow-band first optical filter for receiving the first branched laser beam and transmitting a laser beam having a specific optical wavelength therethrough as a transmitted beam;second and third optical filters for receiving the second and third branched laser beams and transmitting laser beams having specific optical wavelengths therethrough as transmitted beams;first, second, and third photodiodes for converting output beams from said first, second, and third optical filters into electrical signals and outputting the electrical signals as analog voltages;comparator means for comparing the analog voltages output from said second and third photodiodes and outputting a signal representing a comparison result;differential amplifier means for performing differential amplification of a reference analog voltage obtained from said first photodiode and the output signal from said comparator means and outputting a control signal;a temperature adjustment element provided in tight contact with said laser diode and generating heat, a temperature of which is externally controlled; andtemperature adjustment means for controlling the temperature of the heat from said temperature adjustment element on the basis of the control signal output from said differential amplifier means.