| 摘要 |
PURPOSE:To obtain a stable optical switch, by coupling two optical waveguides, which have parts parallel to each other and have different propagation constants, with a prescribed acoustic wave. CONSTITUTION:An optical switch consists of two optical waveguides 2 and 3 which are formed by diffusing titanium on a substrate consisting of a lithium niobate and have parallel parts, an ultrasonic transducer 4, and a sound absorber 5. For optical waves of wavelength lambda=0.8mum of optical waveguides 2 and 3, beta1=17.4437 and beta2=17.4751 are true, and¦beta1-beta2¦=0.0314 is true. Ultrasonic waves having a wave vector component (k) (wavelength lambdaa=200.1mum for m=1) which satisfies k=+ or -¦beta1-beta2¦/m (m is a positive constant) are applied by the transducer 4. The light of lambda=0.8mum which is incident from an end A of the optical waveguide 2 and is outputted to an end B when ultrasonic waves are not applied is transferred to the optical waveguide by application of ultrasonic waves when lengths of parallel parts of optical waveguides 2 and 3 satisfy the phase matching condition, and this light is outputted from an end C. Consequently, a stable optical switch is obtained. |
