| 摘要 |
PURPOSE: To obtain a polarization depending waveguide type optical isolator satisfying the phase conditions of a TE mode and a TM mode simultaneously. CONSTITUTION: This isolator is constituted of a channel waveguide 41 whose refractive index is n1 and a plane waveguide 42 which is adjacent to the waveguide 41 and whose equivalent refractive index is n2 ; and relation n1 >n2 holds. A diffraction grating 44 where 1st and 2nd pitchesΛ1 andΛ2 are alternately repeated is formed at the part of the waveguide 41. Either of the pitchesΛ1 andΛ2 corresponds to the TE mode and the other corresponds to the TM mode. Therefore, two different diffraction grating wave number vectors are obtained and the phase matching condition is simultaneously satisfied for both modes. It is conceivable to set different tilt angles for both modes instead of the pitchesΛ1 andΛ2 . |
