DEVICE FOR GENERATING AND PROPAGATING SURFACE ACOUSTIC WAVE

• Main Authors: YAMASHITA MAKI, INOUE NAOHISA
• Format: Patent
• Language: English
• Published: 22.01.1987
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PURPOSE:To obtain a high deflection efficiency by forming an interdigital transducer (IDT) and a surface acoustic wave (SAW) waveguide on a base board and forming an interdigital electrode of the IDT like a circular arc. CONSTITUTION:Since the interdigital electrode 31 of the IDT 30 is formed like the circular arc, the SAW generated from the IDT is propagated so as to be concentrated into one point. The converged SAW is made incident upon the SAW waveguide 21, the SAW is shut in the waveguide and propagated along the waveguide 21. Thereby, the power of the SAW is concentrated into narrow width and a large change of a refractive index is obtained. Since the SAW propagated through the waveguide 21 is emitted from the end part of the waveguide narrower than the width of the IDT, a practically equivalent effect to the generation of the SAW from the IDT having a short electrode interdigital length is obtained. Consequently, a wide SAW expanding angle is obtained and the deflection efficiency is improved.