| 摘要 |
<p>An optical waveguide characterized in that it comprises an input core (4) and an output core (5) and the width of the output core (5) is 1.5 or more times the width of the input core (4). The optical waveguide can multiplex/demultiplex light even if the wavelength of the light varies in a wide range of about 10 nm. An optical multiplexer/demultiplexer having an optical waveguide through which light travels and a diffraction grating for demultiplexing/multiplexing light, characterized in that the absolute value of the difference between the index of refraction (nTE) in the direction parallel to the plane of the film of the optical waveguide core layer at the wavelength used and the index of refraction (nTM) in the direction perpendicular to the plane of the film of the optical waveguide core layer is 0.007 or less. Since the complex index of refraction of the optical waveguide core layer is 0.007 or less, the wavelength variation of the output signal light depending on the direction of polarization of the input signal light can be reduced to 5 nm or less.</p> |
