Optical semiconductor module with wavelength monitoring

摘要

An optical semiconductor module has a laser diode (1) for emitting light, a first photo-diode (2) and a second photo-diode (3) for receiving light emitted by the laser diode (1), and a wavelength filter (5) which is disposed on a light path between the laser diode (1) and the first photo-diode (2) and continuously changes the intensity according to wavelength of the light. The first photo-diode (2) generates an output current which is 20 % or above larger than that of the second photo-diode (3) at the same intensity of the entered lights. <IMAGE>