Abstract

We have developed a new adaptive spectrum equalizer based on a programmable multifrequency acousto-optic diffraction in TeO₂. The device output is the non diffracted beam which allows small insertion losses. For a given crystal length (25 mm), we maximize the length of interaction by aligning the optical beam with the acoustic Poynting vector.¹ This allows both good spectral resolution (2 nm at 1.5 μm) and high diffraction efficiency (100 mW for total diffraction at single frequency). The optical and acoustical wave vector, satisfying the K-vector conservation rule, are depicted on Fig. 1. The circle and two ellipses in Fig. 1 correspond respectively to the optical slowness curve for the ordinary and extraordinary polarizations and to the acoustical slowness curve. The incident light beam, with unknown polarization, makes an angle θ₀ with the (110) axis of the crystal.

© 2002 Optical Society of America