Optical semiconductor module having a capability of temperature regulation

An optical semiconductor device, comprising:

• a package body;
• a laser diode accommodated in said package body, said laser diode producing an optical beam;
• a temperature regulation part connected thermally to said laser diode, said temperature regulation part having a temperature regulation element and controlling a temperature of said laser diode;
• an optical filter connected thermally to said temperature regulation part, said optical filter having a transmittance curve sloped with respect to a wavelength, said transmittance curve representing a relationship between a transmittance of said optical filter and a wavelength of an optical radiation incident thereto;
• a photodetection part receiving said optical beam from said laser diode via said optical filter, said photodetection part detecting an intensity of said optical beam passed through said optical filter;
• a feeder feeding a driving power to said laser diode;
• and
• a thermal conducting body provided separately to said feeder, said thermal conducting body transmitting a temperature of said package body to said laser diode.