The Theoritical Study And Experimental Fabrication Of Acousto-Optic Tunable Filter

The acousto-optic tunable filter (AOTF) has been widely used in Wavelength Division Multiplexing (WDM), for it has the characteristics of wide tunable range, narrow bandwidth, fast tunable velocity and simultaneous multiwavelength filter. It can be served as optical filter, optical switch and gain equalizers especial applied in Optical Add/Drop Multiplexer (OADM). For the polarization of optical signal in the fiber communication system is random, it requires that the apparatus is not polarization relied. Furthermore, the single stage AOTF can not satisfy the requirement of better filter characteristics in WDM systems. It needs double-stage structure and even more. The main content of this thesis is to make a deeply research in theory of one-stage and double-stage AOTF and fabricate the apparatus.In the second chapter of the thesis, the basic principle of AOTF was introduced, including the effect of acousto-optic, polarization of optical signal, the production and transmitting of SAW (Surface Acoustic Wave), acousto-optic coupling theory. In the third chapter of the thesis, it was introduced how to design and fabric the main part of AOTF, including optical waveguide, mode splitter, surface acoustic waveguide and interdigital transducer. And it worked out the parameters, respectively. In the fourth chapter of the thesis, it designed the double-stage AOTF to replace the single-stage AOTF because of its imitation. Mainly, it introduced to construct double-stage AOTF of using reflector, an(?) got optimum characteristics. The last part of the thesis was for the study of fabrication technologies of AOTF. It introduced the principles of the lithography. With the repetition of the experiment, we fabricated optical waveguide, mode splitter, surface acoustic waveguide and interdigital transducer. Thus an actual AOTF was obtained.