Integrated-optic wavelength multi- and demultiplexers using a chirped grating and an ion-exchanged waveguide

Wavelength multiplexers and demultiplexers using a chirped grating and an ion-exchanged multimode waveguide are presented. The waveguide is prepared by the electric-field-assisted ion-exchange technique, and the chirped grating is fabricated by the computer-controlled electron-beam writing technique. The device requires no collimating and focusing components and has the advantages of (1) high resolution, (2) large channel number, (3) small cross talk, (4) low insertion loss, (5) low loss coupling to multimode fiber, (6) compact and stable rugged structure, and (7) possibility of economical mass production. The design considerations and the fabrication process are described, and the demultiplexing characteristics of the fabricated device are discussed.