Integrated acousto-optic tunable filters in LiNbO/sub 3/ for blue-green spectral region

Abstract

A detailed analysis and calculated performances of guided-wave collinear acousto-optic interactions in X- and Z- cuts of LiNbO/sub 3/ waveguide substrates relevant to tunable optical filtering has been carried out. Calculated performances at five optical center wavelengths (0.5, 0.80, 1.15, 1.31, and 1.55 /spl mu/m) of practical importance with particular emphasis in the blue-green spectral region have been obtained. For example, it was shown that the acoustic drive power requirements for 100% TM/sub 0//spl rarr/TE/sub 0/ mode conversion in the Z-cut configuration is significantly lower than the corresponding values for the TE/sub 0//spl rarr/TM/sub 0/ mode conversion in the X-cut configuration at all optical wavelengths. At the center blue-green spectral region of 0.50 /spl mu/m, an acoustic drive power requirement as low as 0.17 mW/mm for 100% TM/sub 0//spl rarr/TE/sub 0/ mode conversion and an optical bandwidth as narrow as 0.78 nm can be achieved in the Z-cut waveguide (X-propagating SAW) at a guiding layer thickness of 0.6 /spl mu/m, and an interaction length of 30 mm.