Semiconductor laser apparatus, semiconductor laser module, optical transmitter and wavelength division multiplexing communication system

摘要

A semiconductor laser apparatus comprises a light-emitting portion including a light-emitting device for outputting a laser beam, a light-receiving element for receiving the laser beam outputted from said light-emitting device, a wavelength monitoring portion including an optical system disposed between said light-emitting device and said light-receiving element, a control portion for controlling the wavelength of the laser beam outputted from said light-emitting device by controlling the temperature of said light-emitting device based on the wavelength of the laser beam detected by said wavelength monitoring portion, an optical isolator disposed on the optical path between said light-emitting device and said wavelength monitoring portion for preventing the light from returning from said wavelength monitoring portion back to said light-emitting device, and a temperature regulating portion for independently controlling the temperatures of said light-emitting portion and wavelength monitoring portion.