Nippon Telegraph and Telephone Corporation

Oki Electric Industry Co., Ltd.

Ntt Electronics Corporation

Yoshino Gypsum Co., Ltd.

Akira Himeno

Masayuki Okuno

Shinji Mino

Takashi Goh

Motohaya Ishii

Takashi Yamada

Takeshi Kitagawa

Shunichi Souma

Yoshinori Hibino

Yasuyuki Inoue

Takuya Tanaka

Katsunari Okamoto

Manabu Oguma

Akimasa Kaneko

Hiroshi Takahashi

Tsuyoshi Yoshida

Takayuki Mizuno

Makoto Abe

Takashi Saida

Ryo Nagase

Shin Kamei

Masao Kawachi

Tsutomu Kitoh

Kuniharu Kato

Kaname Jinguji

Kiyoshi Kurosawa

Koichi Takiguchi

Mitsuru Nagano

Tomohiro Noguchi

Daisuke Ogawa

Jiro Utsunomiya

Iida Saburo

Toshiyuki Kawashima

Ken-ichi Yukimatsu

Masahiko Naito

Masayuki Okyno

Akihito Doi

Akira Nagai

As a lower forming plate, a forming plate having: a lower plate main bodyconstituted from an electrically conductive material; and a lower embedded electrodeembedded in the lower plate main body, the lower embedded electrodebeing electrically insulated from the lower plate main bodyby an insulatorand being embedded so as for a portion thereof to be exposed on the surface of the lower plate main bodymaking contact with a lower lining paper sheetis used.

Gypsum board manufacturing method and manufacturing device

A planar optical waveguide including a clad layer, an optical waveguide having a core embedded in the clad layer; and a groove formed in the clad layer and having a reflection interface for totally reflecting a leaked light leaked from the optical waveguide to the clad layer. Since the reflection interface for totally reflecting the leaked light is formed in the clad layer, the leaked light is prevented from entering into the tap coupler, and the variation of the branching ratio can be reduced.

Planar optical waveguide

An optical module controls its output characteristics electrically and an optical switch constitutes the optical module. An optical waveguide circuit (PLC) and an electronic circuit (IC) for driving the PLC are mounted on the same substrate. The IC is composed of a bare chip to be molded afterward. Wiring of the IC is grouped and integrated on the PLC substrate to achieve higher density and miniaturization of the optical module.

Optical module and optical switch

Optical module and optical switch constituting the same

An optical module controls its output characteristics electrically and an optical switch constitutes an optical module. An optical waveguide circuit (PLC) and an electronic circuit (IC) for driving the PLC are mounted on the same substrate. The IC is composed of a bare chip to be molded afterward. Wiring of the IC is grouped and integrated on the PLC substrate to achieve higher density and miniaturization of the optical module.

It is an object of the present invention to provide an optical filter which allows parameters to be easily adjusted, which allows birefringence and temperature dependence to be easily compensated for, and which is essentially free from dispersion. The optical filter includes an optical coupler that splits light into two beams, optical couplers connected to outputs of the optical coupler, a first group of two optical waveguide delay lines connected to the coupler, a second group of two optical waveguide delay lines connected to the coupler, an optical coupler that combines lights from the first group of the lines, an optical coupler that combines lights from the second group of the lines, and a multimode interference optical coupler that combines lights from the couplers together.

Optical filter

An optical multi/demultiplexer is provided that has a wide passband and small crosstalk among its all channels. It includes first and second arrayed waveguide gratings and a 2&times;2 optical signal processor. The 2&times;2 optical signal processor includes first to fourth directional couplers, and first to third delay lines. The first to third delay lines have thin film heater phase shifters for correcting phase errors involved in fabrication. Utilizing the 2&times;2 optical signal processor having a transmission spectrum with a square profile having a wide passband and rejection band makes it possible for the optical multi/demultiplexer that combines the arrayed waveguide gratings with the waveguide type circulating filter (2&times;2 optical signal processor) to widen the extinction bandwidth of the adjacent channel.

Optical multi/demultiplexer

A no polarization dependent waveguide type optical circuit can resolve polarization dependency completely and can reduce reflected return light. An intermediate portion of the two connecting waveguides are formed with S-shaped waveguides of the same shape consisted of respectively two curved waveguides or two curved waveguides and straight waveguides connecting the curved waveguides. One polarization mode converter is provided in a groove formed across the S-shaped waveguide, and a perpendicular line to an incident surface of light of the polarization mode converter and the S-shaped waveguide forms an angle greater than 0&deg;.

No polarization dependent waveguide type optical circuit

A frequency stabilized laser using an integrated external cavity, comprising a semiconductor laser diode and an optical waveguide installed on the same substrate, and having an optically induced grating formed in the optical waveguide suppresses mode hopping due to a temperature change to stabilize the oscillation frequencies of the laser. A material having a refractive index temperature coefficient opposite in sign to the refractive index temperature coefficient of the semiconductor laser diode is installed on that portion of the optical waveguide between the semiconductor laser diode and the optically induced grating which has been formed by removing an upper cladding and a core, or removing the upper cladding, the core, and a lower cladding.

Frequency stabilized laser and method for preparing thereof

The present invention provides a wavelength division multiplexing filter that requires lower costs, a smaller size, and a smaller amount of fiber routing operations. According to the present invention, a first module constitutes a first filter. A second module constituting a second filter is produced by connecting together circuits identical in number to a plurality of output ports of the first module, the circuits each comprising a combination of directional couplers and Bragg gratings both formed of silica-based-glass waveguides, the circuits each having a wavelength selection characteristic so as to correspond to each of the output ports. The second module is connected to the first module via an 8-fiber ribbon to simplify the integration and connection of the circuits.

WDM filter

An arrayed waveguide grating including an input waveguide or input waveguides, an input side slab waveguide lens, arrayed waveguides, an output side slab waveguide lens, and an output waveguide or output waveguides, wherein an optical length of the arrayed waveguides monotonically increases or decreases by a constant value between adjacent waveguides; the arrayed waveguides include an input side waveguide block, an intermediate waveguide block, and an output side waveguide block; the intermediate waveguide block includes at least one fan-formed waveguide block, the fan-formed waveguide block is coaxial, equal in vertical angle, and monotonically increases or decreases by a constant value in radius between adjacent waveguides; and the input side waveguide block and the output side waveguide block are line symmetrical about a bisector of the vertical angle of the intermediate waveguide block.

Arrayed-waveguide grating

An optical switching module has an optical waveguide substrate mounted on an electronic circuit substrate. According to a first aspect of the invention, the optical waveguide substrate has thin-film heaters, and the electronic circuit substrate has trimmable thick-film resistors for adjusting current fed to the thin-film heaters. According to a second aspect of the invention, the optical switching module also has a pair of fiber pigtails butt-coupled to the optical waveguide substrate. The fiber pigtails are secured to the ends of a supporter, which is attached to a heat sink fastened below the electronic circuit substrate. According to a third aspect of the invention, the optical waveguide substrate is mounted in a depression in the electronic circuit substrate. The invention reduces the size of the optical switching module.

Compact optical switching module including thin-film heaters and trimmed

Growing community of inventors

Naka-machi, Japan

Akira Himeno