Broadband guided-wave optical frequency translator using an electro-optical Bragg array

Abstract

We describe a new type of optical frequency translator which utilizes Bragg diffraction from a traveling index wave produced by an interdigitated electrode grating on a LiNbO3 surface waveguide. The grating is driven by a three-phase electrical signal that results in a unidirectional wave with a fixed Bragg angle determined by the electrode spacing. The diffraction thus produces a single-sideband suppressed carrier optical output. Measurements at 10 and 100 MHz have yielded greater than 90% carrier-to-sideband conversion efficiency with over 100:1 suppression of the carrier and unwanted sideband. The device should be operable from arbitrarily low frequencies up to several gigahertz.