OPTICAL ISOLATOR, SEMICONDUCTOR LASER DEVICE USING THE ISOLATOR, TERMINAL STATION EQUIPMENT AND OPTICAL COMMUNICATION SYSTEM

摘要

PURPOSE:To provide the optical isolator, semiconductor laser provided with that isolator and optical communication system which are compact and stably operated by equalizing the polarizing planes of incidental/emitted beams. CONSTITUTION:A first optical waveguide 10 provided with both of a waveguide type mode pass filter 18 to pass only the wave-guide light of a TE mode and a non-reciprocal mode conversion waveguide 16 to non-reciprocally rotate the polarizing plane of waveguide light at 45 deg. and a second optical waveguide 12 functioned as a waveguide type mode pass filter to pass only the waveguide light of the TE mode are directly connected so that the polarizing planes of a basic polarization mode to propagate the respective optical waveguides can form an angle at 45 deg. each other. The respective optical waveguides are integrated on the same substrate. Light from a semiconductor laser 22 is emitted in the TE mode, and return light is absorbed by the TE mode pass filter 18.