| 摘要 |
PURPOSE:To obtain the waveguide type light branching element by offering a wide wavelength action waveguide type light branching element whose wavelength dependency of a coupling rate is relaxed in a desired wavelength area. CONSTITUTION:In the coupling area of a directional coupler 2, the width and depth of optical waveguide paths 1a and 1b on both end parts in a parallel area are made different from that of optical waveguide paths 3a, 3b, 4a and 4b in input and output ports, and also the optical waveguide paths 1a and 1b in the coupling area are formed to a smooth-tapered shape, then, the wavelength dependency of a power coupling rate from the input port 3a to the output ports 4a and 4b is relaxed in a specified wavelength area 1.3-1.7mum. |
