Nhk Spring Co., Ltd.

Yuichi Yamamoto

Hisamatsu Nakano

Michiya Masuda

Junji Yamauchi

Ryouichi Tazawa

Shigeru Kawaguchi

An arrayed-waveguide grating type optical multi-demultiplexer includes input waveguides, a first slab waveguide, a channel waveguide array, a second slab waveguide, and output waveguides. A pair of different refractive index regions, each having a refractive index different from that of the second slab waveguide, are formed on the second slab waveguide near a boundary between the second slab waveguide and channel waveguide array. The different refractive index regions project in peninsular shapes from both side portions of the slab waveguide. Light traveling from each waveguide of the channel waveguide array toward the output waveguides passes through the different refractive index regions. An optical distribution with a flattened field-distribution peak is created at a boundary between the second slab waveguide and output waveguides.

Optical multi-demultiplexer

An optical multi-demultiplexer of the present invention comprises an input waveguide to which wavelength division multiple signals are applied, a plurality of output waveguides for demultiplexing and outputting the wavelength division multiple signals, an arrayed waveguide including a plurality of channel waveguides having different waveguide lengths, an input slab waveguide, and an output slab waveguide. The input slab waveguide is provided between the input waveguide and the arrayed waveguide. The output slab waveguide is provided between the arrayed waveguide and the output waveguides. The input slab waveguide is formed with tapered island regions having a refractive index lower than that of the core layer of the slab waveguide. The island regions are situated in positions opposite the channel waveguides of the arrayed waveguide.

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Koganei, Japan

Yuichi Yamamoto