Light-emitting apparatus capable of selecting polarization direction, optical communication system, and polarization modulation control method.

摘要

A light-emitting apparatus capable of selecting polarization direction of a light outputted therefrom includes a semiconductor laser and an optical amplifying device. The semiconductor laser is capable of selectively changing a direction of polarization plane of the output light to one of two orthogonal directions by controlling an excited state. The optical amplifying device amplifies the output light from the semiconductor laser. The optical amplifying device has amplification factors with respect to polarized light components in the two orthogonal directions.