PURPOSE: To obtain an optical deflecting device which can be coupled with an optical fiber efficiently and obtains high deflection efficiency by increasing the width of a light guide gradually toward a light guide layer.
CONSTITUTION: The width of the light guide 16 is nearly as small (width D1) as core diameters of optical fibers 18a and 18b, etc., connected thereto on an end surface of a substrate and increases gradually to the light guide layer 12. Thus, the width of the light guide 16 is increased gradually to increase optical deflection efficiency. A light guide with a constant width of 4μm equal to the core diameter of the optical fibers has deflection efficiency less than 0.1, but the width of the light guide is increased gradually up to 40μm to increase the deflection efficiency by about 0.5 time. When the light guide increases in width gradually so that variation in the width of the light guide when a light wave travels by one wavelength is much smaller than one wavelength, no mode conversion is caused. The variation in the width of the light guide is preferably about 1% of the distance of one wavelength.
MATANO MASAHARU
YAMASHITA MAKI
