To hardly be affected by the change of device temperature and enable maintaining gain, by applying distortion which changes in dependence on temperature to an optical active region, so as to compensate the change generated by temperature at a gain spectraum peak of the optical active region.
The thermal expansion coefficient of a board 9 is set smaller than other thermal expansion coefficients of other layers of a device. This distortion applying means acts via a reflector 10, coping with thermal expansion of an active region 11, and generates compressive distortion of two axes which gradually increases, in the active region. Then the energy gap of an optical active region is increased, and the decrease of the energy gap of the optical active region which is generated by the temperature is compensated at least partially or preferably practically perfectly. Thereby the influence of the device temperature change is reduced, and the gain at a given resonator mode can be maintained.
TEIMOSHII DEEBITSUDO BESUTOUIT
TAKIGUCHI HARUHISA
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