Fujikura Limited

Masaaki Sudoh

Ryozo Yamauchi

Michihiro Nakai

Tetsuya Sakai

Akira Wada

Satoshi Okude

Kensuke Shima

Hiroshi Hidaka

Kuniharu Himeno

Takuya Ienaka

An optical waveguide grating with radiative mode-coupling properties, with exceptional stability and reliability as an optical component, wherein the central wavelength of the rejection band has a low temperature dependence, due to the use of silica glass doped with germanium and boron for the core. The rejection bandwidth can be narrowed without increasing the grating length by forming the radiative mode-coupled optical waveguide grating in an optical waveguide wherein the mean relative refractive index difference of the core is greater than that of optical communication waveguides. The rejection can be increased by reducing the occurrence of cases wherein propagation modes of the core coupled to cladding modes once again couple to the core in palnar optical waveguide gratings formed by making periodic changes in the waveguide structure along the direction of propagation of light in an optical waveguide having a cladding with a lower refractive index than the core surrounding the core, by making the thickness of the cladding at least thirteen times the thickness of the core.

Optical waveguide grating and production method therefor

Core comprises a main stem which is formed on a substrate, linearly extending in the beam propagating direction and short branches with a certain length which extend perpendicularly to the beam propagating direction toward both sides along the plane of the substrate and are arranged at regular intervals in the beam propagating direction. Thus, the branches are arranged in a ladder geometry when it is viewed from the top, forming a rectangular waveform arrangement. The core constitutes a grating structure in which the width of the core is made to vary periodically with the branches in the beam propagating direction.

Optical filter with planar optical waveguide having periodically varied

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Sakura, Japan

Masaaki Sudoh