OPTICAL WAVEGUIDE FORMED OF LOW-REFLECTION GRATING AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To manufacture an optical waveguide in which the low-reflection grating having rectangular spectrum characteristics is formed. ;SOLUTION: This optical waveguide 5 is so constituted that a core 5a where a grating having a periodic uneven refractive index distribution in the propagation direction of light wherein light of specific wavelength should be reflected is formed is covered with a clad 5b which has a smaller refractive index than the core 5a. In this case, many gratings G which have different periods are superposed on the core 5a of the optical waveguide 5a to generate beats, and the envelope of the beats has a shape close to sin(X)/X based upon a line representing an increment of the mean refractive index of the core as an X axis, so the low-reflection grating is obtained which has rectangular spectrum characteristics of the refractive index distribution.;COPYRIGHT: (C)1998,JPO