INTEGRATED-OPTIC ACOUSTICALLY-TUNABLE FILTERS FOR WDM NETWORKS

Acoustically-tunable optical Alters have the combined virtues of narrow passband (subnanometer bandwidth), broad tuning range (hundreds of nanometers have been demonstrated), and simultaneous independent multiple-channel filtering. In this paper, the theory and practice of collinear integrated-optic acoustooptic filters is presented. The main advantage of integrated optics is the potential for low power consumption, allowing efficient multichannel operation to be realized. In addition, integrated optics allows for the reduction of rather complex optical circuits to a single substrate, with the attendant advantages of uniformity, stability, and the potential for low cost fabrication. Devices which involve higher order integration are discussed, including multiple-stage filters for enhanced sidelobe suppression and polarization-independent configurations. Various sources of inter-channel crosstalk are derived and demonstrated in multiwavelength filtering experiments. © 1990 IEEE