Optical apparatus and a method using the apparatus, which utilizes the occurrence of a change in a both-end voltage of an amplifying region

摘要

In an optical apparatus, such as a semiconductor optical amplifier device and an optical filtering apparatus, there are provided an optical amplifier device, a detector and a controller. The optical amplifier device has such a structure that exhibits a both-end voltage change at an optical amplification time of an input light. The detector detects the both-end voltage change, and the controller performs a predetermined control of a portion other than the optical amplifier device, such as another optical amplifier portion and a tunable band pass filler portion.