Add/drop filters and multiplexers fabricated from cladding mode couplers and fiber bragg gratings

摘要

An optical fiber add/drop filter includes a first and second elongate photosensitive optical fiber, each optical fiber having opposed first and second ends and including a core and a cladding. The cladding of the first optical fiber is optically coupled to the cladding of the second optical fiber at a coupler. A first fiber Bragg grating is etched into a second end of the first fiber for converting light propagating in a first direction through either of the core of cladding of the first fiber into light propagating in an opposite direction through the other of said core and cladding of said second fiber. A second fiber Bragg grating is etched into a first end of the second fiber for converting light propagating in a first direction either of the core or cladding of the second fiber into light propagating in an opposite direction through the other of the core and cladding of the second fiber. The first and second fiber Bragg gratings are located to opposite sides of the coupler. The add/drop filter of the present invention may be cascaded to form an optical add/drop multiplexer.