| 摘要 |
PURPOSE:To eliminate instability of optical system derived from vibrations, by selecting the refractive index so that the wavelength dependency of propagation constant of first wave guide differs from that of second waveguide. CONSTITUTION:Propagation lights of wavelength lambda0 and lambda1 are inputted from the left side end 15 of waveguide, and the propagation light of wavelength lambda0 only is bonded. The propagation light of wavelength lambda0 is also bonded in the part Z = 0 - e of wavegide II, and this propagation light reciprocates between the two waveguides. The waveguide layer 10 in waveguide II is tapered in the y-direction, and the equivalent refraction of waveguide II increases as the film thickness Wd of the waveguide layer 10 grows thicker. When the equivalent refractive index of the waveguide II changes, propagation constant beta2 also changes, but by changing the equivalent refractive index slightly, mismatching DELTAbeta of the propagation constant may be kept almost at zero. |
