| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a waveguide type optical device which is small-sized, is capable of separating or combining polarized waves, and has low loss. <P>SOLUTION: An optical waveguide including an optical waveguide for input and an optical waveguide for output is formed on a substrate, and a 3 dB coupler for input and a 3 dB coupler for output are provided, and two optical waveguides are provided between the 3 dB coupler for input and the 3 dB coupler for output. The two optical waveguides constitute arms of a Mach-Zehnder waveguide which includes a wide optical waveguide and a narrow optical waveguide having mutually different widths at least partially so that equivalent refractive indexes of propagated light are different due to structural birefringence. TE-mode light and TM-mode light incident from the optical waveguide for input is divided by about 3 dB after passing the 3 dB coupler for input, and light divided by about 3 dB has the phase changed by different amounts due to propagation through the wide optical waveguide and the narrow optical waveguide, so that a wave in mixture of TE and TM modes is propagated through the optical waveguide for output after passage through the 3 dB coupler for output. <P>COPYRIGHT: (C)2012,JPO&INPIT |
