CLAD MODE COUPLER, ADD/DROP FILTER FORMED BY BRAGG FIBER GRATING AND MULTIPLEXER

摘要

PROBLEM TO BE SOLVED: To easily and reliably manufacture an optical fiber add/drop filter without requiring an accurate positioning of each element and conducting a phase matching. SOLUTION: An optical fiber add/drop filter 10 is provided with first and second optical fibers 12 and 14 which are slender in their shapes, are photosensitive, have opposing first and second tip parts and include cores 16 and 18 and claddings 20 and 22. The cladding 20 of the fiber 12 is optically coupled to the cladding 22 of the fiber 14 at a coupler 24. A first Bragg fiber grating 34 is etching formed at a second tip part of the fiber 12. A second Bragg fiber grating 36 is etching formed at a first tip part of the fiber 14.