PURPOSE: To efficiently generate a surface acoustic wave which can Brag-diffract an optical beam and, at the same time, to miniaturize an acoustic optical element, by providing the 1st and 2nd electrode fingers in such a way that they are arranged alternately and in parallel with fixed intervals between them and an inclined linear section in which each common electrode intersects corresponding electrode fingers at an angle other than right angle.
CONSTITUTION: A surface acoustic wave generating device (IDT) 30 is equipped with a pair of common electrodes 31 and 32 and a pair of bonding terminals 35 with an appropriate interval in-between. One 31 of the electrodes 31 and 32 is extended from one 35 of the bonding terminal 35 in the direction of the optical path of optical bits a1, a2, etc., and refracted with an angle [90°+θ] from the halfway. When a switch 26 is instantaneously turned on and a high frequency signal is impressed upon the IDT30, surface acoustic waves are generated from the IDT30 and propagated toward the optical path (in the direction intersecting electrode fingers 33 and 34). Since the common electrodes 31 and 32 of the IDT30 are respectively equipped with inclined linear sections 31b and 32b, it is possible to set the area of the surface acoustic wave and optical path of the optical bit signals in such a way that they nearly overlap each other when the switch 26 turning-out timing is appropriately fixed.
TAKAGI JIYUNICHI
OGATA SHIROU
INOUE NAOHISA
YAMASHITA MAKI
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