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 μm). 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.
© 1989 Optical Society of America
Original Manuscript: June 2, 1989
Manuscript Accepted: August 16, 1989
Published: November 1, 1989
D. A. Smith, J. J. Johnson, J. E. Baran, V. S. Shah, L. Curtis, and K. W. Cheung, "Integrated-optic acoustically tunable reflection filter," Opt. Lett. 14, 1240-1242 (1989)