| 摘要 |
PURPOSE:To improve diffraction efficiency over a wide frequency range by making the central frequency of one of at least two transducers disposed adjacently to each other coincident with the trap frequency of the other transducer. CONSTITUTION:Incident light 2 is propagated in an optical waveguide 1 consist ing of Ti-diffused LiNbO3. Comb-shaped transducers (IDT) 3-6 having different angles of inclination with the incident light 2 are disposed. The central frequency of one of the adjacent transducers is made coincident with the trap frequency of the other transducers. For example, the central frequency fD of the transducer 4 is made coincident with the trap frequency of the transducers 3, 5. Diffracted light 8 is generated by the surface acoustic wave SAW7 emitted by the IDT4 and the incident light 2 and part thereof advances rectilinearly in the form of non-diffracted light 9. The highly efficient diffraction is thus made possible over a wide frequency range. |
