PLANAR OPTICAL-OPTICAL SWITCH

摘要

PROBLEM TO BE SOLVED: To provide a planar optical-optical switch which greatly increases an extinction ratio. SOLUTION: A planar optical-optical switch utilizing the saturable absorption characteristic of a semiconductor multiple quantum well layer 11 has a polarizer 12 which excites only one spin state corresponding to the clockwise rotation and counterclockwise rotation of circularly polarized light, and at the time of causing transition of the excition of the semiconductor multiple quantum well layer 11 with pumping light in a circularly polarized light state, changes the absorption characteristic to the light of the clockwise and counterclockwise circularly polarized light included in the signal light of the linearly polarized light and has a polarizer 12 which intersects orthogonally with the polarized light of the signal light on its output side.