Abstract: The present invention relates to an optical fiber having a sufficient strength, in which not only a core region but also a cladding region contains GeO2, and an optical component including the same. The optical fiber has an outer diameter D; and comprises a core region, a first cladding region surrounding the core region, and a second cladding region surrounding the first cladding region. The core region is a glass region mainly composed of a silica glass material with a GeO2 content of 1 wt % or more. The first cladding region is a glass region, mainly composed of a silica glass material with a GeO2 content of 1 wt % or more, having an outer diameter of 0.80D or more but 0.98D or less. The second cladding region is a glass region mainly composed of a silica glass material with a GeO2 content of less than 0.2 wt %.

Abstract: An optical communication system comprises an optical circulator and an optical component. The optical circulator has first, second, and third ends, outputs from the second end light fed into the first end, and outputs from the third end light fed into the second end. The optical component includes an optical waveguide type diffraction grating device connected to the second end of the optical circulator and provided with a plurality of refractive index modulation forming areas, disposed along the longitudinal direction of an optical fiber, for Bragg-reflecting a predetermined wavelength of guided wave. A predetermined region including the boundary position between two refractive index modulation forming areas adjacent each other in the optical waveguide type diffraction grating device is heated by a thin film heater, so as to adjust the optical path length thereof.

Abstract: The present invention relates to an optical device and the like which can facilitate a fine adjustment for an optical waveguide type diffraction grating device. The optical device includes a flexible member in which the optical waveguide type diffraction grating device is secured to a predetermined position, and bending means for applying a stress to said optical waveguide type diffraction grating device by bending said flexible member. The optical device changes the optical characteristics of the optical waveguide type diffraction grating device by adjusting the stress applied thereto by the bending means, to thereby perform easily various functions such as optical multiplexing, optical demultiplexing, path changing, and adjustment of dispersion characteristics.

Abstract: The present invention relates to an optical fiber having a sufficient strength, in which not only a core region but also a cladding region contains GeO2, and an optical component including the same. The optical fiber has an outer diameter D; and comprises a core region, a first cladding region surrounding the core region, and a second cladding region surrounding the first cladding region. The core region is a glass region mainly composed of a silica glass material with a GeO2 content of 1 wt % or more. The first cladding region is a glass region, mainly composed of a silica glass material with a GeO2 content of 1 wt % or more, having an outer diameter of 0.80D or more but 0.98D or less. The second cladding region is a glass region mainly composed of a silica glass material with a GeO2 content of less than 0.2 wt %.