title: Low-loss all-fiber acousto-optic tunable filter.
abstract: We report significant advances in the development of simple all-fiber, tunable acousto-optic spectral filters based on null couplers. The performance agrees well with theoretical predictions and is attributed to improved control of the coupler uniformity. Furthermore, using a double-pass arrangement, we demonstrate filter bandwidth reduction and improved sidelobe suppression of -20 dB . The double-pass configuration is also shown to double the frequency shifts that are obtainable from such devices.
authors.forename: D O
authors.initials: DO
authors.lastname: Culverhouse
authors.forename: S H
authors.initials: SH
authors.lastname: Yun
authors.forename: D J
authors.initials: DJ
authors.lastname: Richardson
authors.forename: T A
authors.initials: TA
authors.lastname: Birks
authors.forename: S G
authors.initials: SG
authors.lastname: Farwell
authors.forename: P S
authors.initials: PS
authors.lastname: Russell