Integrated-optic acoustically tunable reflection filter

Abstract

We demonstrate a two-stage, integrated-optic, acoustically tunable filter formed by reflecting the output of a single stage acousto-optic filter back through the filter by means of an integral mirror. Relative to a single-stage device, this double-pass configuration provides greatly improved sidelobe suppression (to approximately -20 dB) and a 72% reduction in filter bandwidth (to less than 0.9 nm at a wavelength of 1.52 microm). The performance of this device is shown to be equal to the far more difficult to fabricate cascaded pair of strictly matched acousto-optic filters.

Design of tapered SAW waveguide for wavelength‐selective optical switches using weighted acoustooptic interaction

“…This approximation of the first-order perturbation is valid when the next order term of v′(h) − v 0 given by is negligible compared to δ(h)Ω given by Eq. (6). The derivation of Eqs.…”

“…When the device is used as a constituent of optical circuits such as a matrix switch, the sidelobe is required to decrease to less than around -30 dB [5]. One simple approach to reduce the sidelobes is to connect multiple modules in cascade [6,7]. By connecting two modules, for example, the sidelobe is suppressed to -18.6 dB.…”

Low-loss all-fiber acousto-optic tunable filter

“…Because of the inherent low-loss of the filter, multiple passes through the device can be used to obtain both narrowing of the transmission peak and (more importantly) additional suppression of the sidelobes. 6 To investigate this possibility, we constructed a more complex filter with the addition of a circulator and a mirror conf igured as in Fig. 4.…”