Abstract

Acoustooptical Tunable Filter with High Resolution

M.Pushkareva, V.N.Parygin (Department of Oscillation Physics, Faculty of Physics, Moscow State University, Moscow, Russia)

e-mail: marina@osc162.phys.msu.su

The report is devoted to acoustooptics. The spectral selectivity of acoustooptical interaction in the case of Bragg's diffraction makes it possible to use an acoustooptical cell as a filter(AOTF). This device is easily tunable and can be used in a wide range of frequencies. AOTF is used in Wavelength Multiplexing Division Systems (WDM) to choose one of several signals propagating simultaneously in one fiberoptical network. The quantity of channels in WDM Systems can be increased by enlarging the resolution of AOTF. The filter with best characteristics was obtained on the crystal of tellurium dioxide on the wavelength 1550 nm with quasi-collinear configuration. Slow shear ultrasonic waves propagate at the angle equal to 4.5 with respect to the (110) direction in the (110) plane. The best obtained resolution (R) in this case is 3400. This value can be improved by displacing the interaction in other planes of the crystal. A special program was designed to solve the acoustical, optical and acoustooptical tasks by defining the constants of the crystal, sound and light waves. One of the most promising direction of interaction with high energetic characteristics and good value of resolution was found. The value of resolution in this filter is more than 6400. So the number of propagating channels in WDM systems could be enlarged more then twice.

Section : 9