The Furukawa Electric Co., Ltd.

Toshiyuki Inukai

Kazuhiko Kashima

Yasuo Uemura

The present invention provides a fiber Bragg grating element which is simply configured and capable of obtaining a high cut-off amount exceeding 40 dB in a wide range. A fiber Bragg grating element of the present invention has a plurality of gratings formed in an optical waveguide having a core and a cladding around the core thereby to perform high rejection filtering on an input optical signal over a desired bandwidth&#x2dc; the gratings being formed with a grating pitch between adjacent two of the gratings increasing toward a center in a longitudinal direction of the optical waveguide.

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Tokyo, Japan

Toshiyuki Inukai