Integrated acousto-optic tunable filters in LiNbO3 for blue-green spectral region

A detailed analysis and calculated performances of guided-wave collinear acousto-optic interactions in X- and Z- cuts of LiNbO₃ 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 μm) 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% TM₀→TE₀ mode conversion in the Z-cut configuration is significantly lower than the corresponding values for the TE₀→TM₀ mode conversion in the X-cut configuration at all optical wavelengths. At the center blue-green spectral region of 0.50 μm, an acoustic drive power requirement as low as 0.17 mW/mm for 100% TM₀→TE₀ 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 μm, and an interaction length of 30 mm