OPTICAL BRANCH UNIT, OPTICAL AMPLIFICATION DEVICE, AND OPTICAL AMPLIFICATION METHOD

摘要

PROBLEM TO BE SOLVED: To make branch ratio of light variable without using active control.SOLUTION: Input light passing through a faraday rotator 141 is branched for each polarization component by a polarization beam splitter 142. At that time, by using force accompanied with deformation of a member 30 deformed depending on temperature, relative positional relation between the faraday rotator 141 and magnets 145 and 146 is controlled.