| CPC H01S 5/0265 (2013.01) [H01S 5/0601 (2013.01); H01S 5/0617 (2013.01); H01S 5/06804 (2013.01); H01S 5/06808 (2013.01)] | 19 Claims |
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1. A semiconductor laser device comprising:
a modulator-integrated semiconductor laser including a semiconductor laser, an electro-absorption modulator, and an optical attenuator that are monolithically integrated, the electro-absorption modulator and the optical attenuator being connected in series in a stage succeeding the semiconductor laser; and
a control unit controlling the DC bias voltage to be applied to the optical attenuator as reverse bias to increase as temperature of the modulator-integrated semiconductor laser rises so that an average light output from an emission end surface of the modulator-integrated semiconductor laser becomes constant regardless of temperature,
wherein DC bias current of the semiconductor laser is constant regardless of temperature,
the control unit reads a bias current value of the semiconductor laser which corresponds to the temperature from a look-up table and sets a bias current of the semiconductor laser to have the read bias current value,
the control unit reads a bias voltage value of the electro-absorption modulator which corresponds to the temperature from the look-up table and sets bias voltage of the electro-absorption modulator to have the read bias voltage value, and
the control unit reads a bias voltage value of the optical attenuator which corresponds to the temperature from the look-up table and sets bias voltage of the optical attenuator to have the read bias voltage value.
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