Integrated acoustically tunable optical filters: devices and applications

With the advent of ever more broadly tunable laser sources and filters, wavelength-division multiplexing has become a practical approach to high-capacity optical communication. The acousto-optic filter has a large tuning-range-to-channel-spacing ratio (250:1 nm), has low power consumption (10 mW per channel demonstrated to date1) and has been fabricated in a polarization-independent configuration (see Fig. 1).2