Unidirectional operation of a ring laser by means of anisotropic acousto-optic device

The dependence of nonreciprocal behavior of AO device on ultrasonic wave signals was investigated by means of Bragg diffraction equation. The result showed that through choosing Suitable ultrasonic frequencies input to AO device, unidirectional operation in ring laser could be achieved without mechanical rotation. Furthermore, the use of narrowband AO device, acousto-optic tunable filter (AOTF) as a unidirectional operation element for the ring cavity laser was investigated in theory and experiment. The result showed that it could induce a high loss difference for the counter-rotating beams, while keeping the low diffraction loss at an appropriate radio frequency. This indicates that AOTF is attractive for use as an optical diode for unidirectional operation in ring cavity lasers. (C) 2002 Published by Elsevier Science B.V.