MODE MULTIPLEXER/DEMULTIPLEXER AND MODE MULTIPLEX COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a mode multiplexer/demultiplexer that enables three-mode multiplex transmission on an optical waveguide that is restricted such that its height is constant.SOLUTION: A mode multiplexer/demultiplexer comprises: a first waveguide 114 for propagating an LP01 mode; a second waveguide 112 for propagating an LP11b mode; a third waveguide 113 for propagating an LP21 mode; a fourth waveguide 111 for propagating the LP01 mode; a fifth waveguide 115 for propagating an LP11a mode; and a mode rotator 130 for connecting the fifth waveguide 115 and the second waveguide 112, for rotating LP11a-mode light of the fifth waveguide 115 to LP11b-mode light to input it into the second waveguide 112, and for rotating the LP11b-mode light of the second waveguide 112 to LP11a-mode light to input it into the fifth waveguide 115.