Isolation of a new structural acousto-optic switch based on an integrated optical polarization-independent quasi-collinear acousto-optic tunable filter (AOTF) is studied in detail. First, we demonstrate the structure and operation principle of this optical switch. Second, factors that influence isolation of the optical switch are analyzed, and expressions of the isolation are deduced. Finally, the optical switch is fabricated, and its isolation is measured in experiment. We show that the isolation mainly depends on the TE/TM mode intensity ratio when the radiofrequency signal is absent, but the isolation mainly depends on the mode conversion efficiency when the radiofrequency signal is present.
As an optical communication component with considerable potential, the Integrated Optical Acousto-optic Tunable Filter (IAOTF) has been paid great attention in recent years. With the advantages of low insertion-loss, broad tuning range, continual electric-tuning with high speed and simultaneous multiple-channel filtering, it has promising prospect in the future in a1l-optic networks. At first, the paper introduces acousto-optic coupling principle of AOTF briefly. Secondly, it concretely analyses the existing problems and the solutions of every developing stage with the research work of our laboratory. Finally, according to the developing trend of optical communication, we put forward a simple analysis of AOTF's developing direction and the method of improving AOTF's performance.