| 摘要 |
<P>PROBLEM TO BE SOLVED: To split output light in any proportion while using a 3dB directional coupler in a Mach-Zehnder interferometer. <P>SOLUTION: An optical device comprises an optical waveguide 11 composed of a clad 12 provided on a main face 8a side of a substrate 8 and a core 18 provided in the clad. The optical waveguide includes a first and a second optical waveguide 16a and 16b, and has a first and a second directional coupler 22L and 22R composed of the first and second optical waveguides that are arranged in parallel and separated away from each other by a distance allowing optical coupling, and an arm part 22C composed of the first and second optical waveguides intervening between the first and second directional couplers. The first and second directional couplers function as 3dB couplers in regard to first light of a first wavelength λ<SB POS="POST">1</SB>. The arm part gives a phase difference of (2m+z)π to the first light propagating through the arm part (where m is an integer more than 0, and z is a real number satisfying 0<z<1). <P>COPYRIGHT: (C)2013,JPO&INPIT |
