MODE MULTIPLEXER/DEMULTIPLEXER

摘要

PROBLEM TO BE SOLVED: To more efficiently perform multiplexing/demultiplexing in any of two or more propagation modes.SOLUTION: A mode multiplexer/demultiplexer includes: a plurality of single mode waveguides 111 and 112 having different waveguide widths; and one multi-mode waveguide 113 propagating multimode light which has a mode number more than the number of the single mode waveguides and in which a coupling part with each single mode waveguide is arranged in a longitudinal direction. The single mode waveguides 111 and 112 has a waveguide width such that an effective refractive index in a basic mode is equal to one effective refractive index in a higher mode propagating the multi-mode waveguide 113. A coupling efficiency of the single mode waveguides 111 and 112 with the multi-mode waveguide 113 in a use wavelength band has interaction lengths Land Lto be equal to or more than a desired value.