| abstract |
[PROBLEMS] To increase the output of a semiconductor laser device, reduce noise, and reduce the size of a housing. SOLUTION: A semiconductor laser device 1 has a laser oscillation region 2a, a wavelength selection region 2b having a chirped grating, a wavelength variable region 3 for converting the wavelength of laser light, and a well layer having the same thickness on the same semiconductor substrate. It has an amplification region 4 having a different multiple quantum well structure. The frequency of the laser light oscillated in the laser oscillation region 2a is selected in the wavelength selection region 2b, the wavelength is converted to the wavelength variable region 3, and further, the laser light is Are amplified and output from the output end face 5. |