Sumitomo Electric Industries, Limited

Ken Hashimoto

Akira Inoue

Masaki Ohmura

Toshikazu Shibata

Kiyotaka Murashima

Shinji Ishikawa

Masakazu Shigehara

Manabu Shiozaki

Toru Iwashima

The present invention relates to an optical waveguide type grating element and others in structure for decreasing absolute values of chromatic dispersion occurring in selective reflection of each of signal channels in a reflection band. The optical waveguide type grating element is provided with an optical waveguide in which signal light containing a plurality of signal channels spaced at a channel spacing &#x3bb;propagates, and a grating which is an index modulation formed over a predetermined range of the optical waveguide. Particularly, the optical waveguide type grating element has a transmittance of &#x2212;20 dB or less for each of the signal channels in the reflection band, and has a reflectance of &#x2212;20 dB or less for each of signal channels outside the reflection band. Furthermore, a deviation of a group delay time of each of the signal channels in the reflection band, which is caused by reflection in the grating, is 10 ps or less in a wavelength range of (&#x3bb;&#x2212;&#x3bb;&#xd7;0.375/2) or more but (&#x3bb;+&#x3bb;&#xd7;0.375/2) or less, where &#x3bb;is a center wavelength of each signal channel.

Optical waveguide type grating element, production method thereof, multiplexer/demultiplexer module, and optical transmission system

In a diffraction grating device (), index modulations are formed along the longitudinal direction of an optical fiber () serving as an optical waveguide. The optical fiber () has a core region (), an inner cladding region (), and an outer cladding region () sequentially from the optical axis center. Index modulations are formed in both the core region () and the inner cladding region () of the optical fiber () in each of a plurality of regions Ato A(N is an integer; N&#x2267;2) separated from each other along the longitudinal direction of the optical fiber (). In the diffraction grating device (), regions A(n=1 to N) in which index modulations are formed in both the core region () and the inner cladding region () and regions B(n=1 to N&#x2212;1) in which no index modulations are formed alternately exist along the longitudinal direction.

Diffraction grating device

In a method of making a diffraction grating device, an optical waveguide is irradiated, by way of a phase grating mask, with refractive index modulation inducing light so as to form a diffraction grating in the predetermined region. This method comprises (1) a step of measuring a diffraction efficiency distribution of the phase grating mask; and (2) a step of longitudinally scanning the optical waveguide with the refractive index modulation inducing light by way of the phase grating mask and irradiating the optical waveguide with the refractive index modulation inducing light so as to modulate a refractive index of the predetermined region. Upon scanning with the refractive index modulation inducing light, longitudinal relative positions of the phase grating mask and optical waveguide are changed according to the diffraction efficiency distribution of the phase grating mask.

Method of making diffraction grating device, diffraction grating device, and apparatus for making diffraction grating device

In this diffraction grating device manufacturing method, refractive-index-change-inducing light of a wavelength that induces a change in refractive index is irradiated onto an optical waveguide, thus forming a diffraction grating through refractive index modulation along the longitudinal direction of the optical waveguide. At this time, the position of irradiation of the refractive-index-change-inducing light onto the optical waveguide is swung in a direction perpendicular to the longitudinal direction of the optical waveguide.

Diffraction grating device manufacturing method, diffraction grating device manufacturing apparatus, and diffraction grating device

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 GeO , 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 GeO content of 1 wt % or more. The first cladding region is a glass region, mainly composed of a silica glass material with a GeO 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 GeO content of less than 0.2 wt %.

Optical fiber and optical component including the same

The present invention relates to a method of making a diffraction grating device, in which an optical waveguide is irradiated, by way of a phase grating, with light capable of inducing a refractive index modulation in an optical waveguide region of the optical waveguide so as to form a diffraction grating in the optical waveguide region. In the present invention, when modulating the refractive index of the optical waveguide region of an optical fiber, the intensity of refractive index modulation inducing light emitted from a laser light source so as to irradiate the phase grating is adjusted according to individual positions on the phase grating. Alternatively, the scanning speed of a mirror scanned by a stage is adjusted according to the individual positions on the phase grating. Here, the amount of irradiation of refractive index modulation inducing light at each position on the phase grating is adjusted so as to cancel the diffraction efficiency distribution of phase grating. The present invention can make a diffraction grating device having a desirable characteristic even when the diffraction efficiency distribution of phase grating deviates from its desirable distribution.

Growing community of inventors

Yokohama, Japan

Ken Hashimoto