Hitachi, Ltd.

Opnext Japan, Inc.

Nippon Telegraph and Telephone Corporation

Hitachi Cable, Inc.

Hitachi Tohbu Semiconductor, Ltd.

Shinji Tsuji

Naoki Chinone

Motohisa Hirao

Hiroyoshi Matsumura

Hitoshi Nakamura

Makoto Okai

Kazuhisa Uomi

Shinji Sakano

Masato Shishikura

Satoru Kikuchi

Akio Ohishi

Takeshi Kato

Hiroshi Sato

Hiroki Yamashita

Tadashi Fukuzawa

Yoshihisa Fujisaki

Masataka Shirai

Kazunori Shinoda

Yasunobu Matsuoka

Takao Mori

Michiharu Nakamura

Takao Kuroda

Kenji Hiruma

Takashi Takemoto

Akira Taike

Yasutoshi Kashiwada

Atsutoshi Doi

Akira Arimoto

Satoshi Aoki

Koichiro Adachi

Masahiro Aoki

Kimio Tatsuno

Toshiki Sugawara

Kazuhiro Ito

Masahiro Ojima

Yuichi Ono

Kazumi Kawamoto

Ryoji Takeyari

Kouji Nakahara

Hiroaki Inoue

Tsukuru Ohtoshi

Tatsuo Harada

Shigehisa Tanaka

Hideo Arimoto

Kouji Yoshida

Toshiaki Kita

Ryuta Takahashi

Junichiro Shimizu

Toshinori Hirataka

Junji Shigeta

Sumiko Fujisaki

Makoto Haneda

Etsuko Nomoto

Makoto Shimaoka

Hisao Nakashima

Yutaka Takeda

Hiroyoshi Matumura

Akiyoshi Watanabe

Takashi Toyonaka

Toshiyuki Mogi

Tomohiro Ohno

Hideki Taira

Takashi Tayonaka

Yoichi Yasuda

Akio Oishi

Aiko Ohishi

An optical module including a transimpedance amplifier capable of realizing a high-speed and high-quality receiving operation is provided. A transimpedance amplifier includes: a pre-amplifier using a single-end current signal as an input and converting the single-end current signal to a single-end voltage signal; an automatic decision threshold control detecting a center electric potential of the single-end voltage signal serving as an output of the pre-amplifier; a post-amplifier differentiating and amplifying the single-end voltage signal of the output of the pre-amplifier; and a power circuit supplying power to the pre-amplifier. Particularly, in accordance with an input voltage signal or an output voltage signal of the pre-amplifier, the power circuit outputs a varied current that flows to a supply terminal of the pre-amplifier and a varied current having a phase opposite to that of the varied current. Thus, the power supply current change is cancelled out.

Transimpedance amplifier, semiconductor device, and optical module to include an adding circuit for adding first and second current variation

Specifically, provided is a horizontal-cavity surface-emitting laser including, on a semiconductor substrate: a cavity structure; a waveguide layer; and a reflecting part, wherein a first electrode provided on the semiconductor substrate along side regions of the cavity structure and the reflecting part and a second electrode provided on the main surface of the cavity structure are provided, the first electrode includes an electrode (1) that is provided around one side region of the reflecting part located in the direction intersecting with the traveling direction of light guided through the waveguide layer and an electrode (2) provided around one side region of the cavity structure and the other side region of the reflecting part that are located in the direction parallel with the traveling direction of light guided through the waveguide layer, and the shape of the electrode (2) has different widths at at least two positions.

Horizontal-cavity surface-emitting laser

An optical communication module and an optical communication device including the same are provided. For example, a first semiconductor chip on which a laser diode is formed and a second semiconductor chip on which a laser diode driver circuit, etc. for subjecting the laser diode to drive by current are formed are mounted on a package printed circuit board to be close to each other. Temperature detecting means is further formed on the second semiconductor chip (laser diode driver circuit, etc.). The temperature detecting means detects a temperature variation &#x394;T of the first semiconductor chip (laser diode) transmitted via a wiring in the package printed circuit board and controls the magnitude of the driving current of the laser diode driver circuit based on a detection result.

Optical communication module and optical communication device

The semiconductor optical device is mounted junction down on a mounting plate via the solder metal of the mounting plate. The electrode of the semiconductor optical device facing the mounting plate is partially coated with a dielectric film and the dielectric film is in contact with the solder metal on the mounting plate. The reaction between the semiconductor optical device and the solder metal of the mounting plate can be suppressed without deteriorating the thermal conductivity between the semiconductor optical device and the mounting plate. Therefore, it is possible to improve the reliability of the semiconductor optical device mounted in the junction down form since diffusion of the solder metal into the semiconductor can be prevented.

Optoelectronic waveguiding device, structural body including the same, and optical module

The present invention provides a highly reliable ridge-waveguide semiconductor laser diode and an optical module. The p-side electrode of the ridge-waveguide laser diode has a first conductor layer region and a second conductor layer region formed on the first conductor layer region. At least one of facets of the second conductor layer region is recessed inward from a reflection facet. Thus, the ridge-waveguide semiconductor laser diode has a structure in which strain which is caused by the electrode stress to be applied on the diode facet is reduced and the saturable absorption does not occur. The ridge-waveguide semiconductor laser diode thus obtained is highly reliable, and the optical module using the same is remarkably high in reliability.

Semiconductor laser diode and optical module

An optical transmission device suitable for a high-speed and large-capacity optical transmission system. An optoelectronic waveguiding device including an optical waveguide layer and cladding layers each having a larger band gap than that of the optical waveguide are deposited above and beneath the optical waveguide layer formed on a semiconductor substrate. The waveguide and cladding layers comprise optical waveguides each having a MQW structure in a direction of a light propagation axis of the optical waveguide layer. Among these optical waveguides, there exists first and second optical waveguides, whose layer structures may be mutually different. The optoelectronic waveguiding device maybe characterized in that an optical waveguide made of a bulk crystal exists in a connection part between the MQW structure waveguides each having a different layer structure. The specific connected optoelectronic waveguiding device elements may include semiconductor lasers, modulators and/or amplifiers.

Optoelectronic waveguiding device and optical modules

An optical modulator having a good reflection characteristic over a broad band is provided, with a small semiconductor chip area, by use of a semiconductor chip on which a semiconductor optical modulator is mounted. A typical example of the optical modulator has a structure in which a semiconductor chip provided with an electro-absorption semiconductor optical modulator comprising an electrode of traveling wave modulator is mounted on a dielectric substrate provided with a transmission line, and the characteristic impedance of at least a part of the transmission line is set to be greater than the output impedance of a modulator driver circuit and the impedance of an optical modulator portion. By this, a broad band optical modulator with excellent reflection characteristic can be provided by use of a semiconductor chip which is small in area.

Traveling wave optical modular

A module for optical communication intended for decreasing the consumption power of a modulator integrated laser, in which a, multiple-quantum well constituting a laser active layer region comprises InGaAlAs/InGaNAs to keep the reliability and optical power level even when a chip is kept at a high temperature, and the difference of wavelength between the oscillation wavelength and the band gap wavelength of the modulator and the laser should be made greater in proportion with the elevation of the chip setting temperature for maintaining the transmission performance, by which the temperature difference between the module case temperature and the chip setting temperature is reduced to decrease the module consumption power.

Module for optical communications

In aiming at cost lowering of an optical module and an optical transmission apparatus and with the objective of providing a semiconductor light receiving element that has a good coherence with the other edge emitting/incidence type optical devices and is capable of performing the positioning easily and with a high accuracy, in the edge emitting/incidence type light receiving element in which the light absorbing layer has been formed, the space region is formed so as to provide at least 100 &mgr;m of the marker detecting region , thereby facilitating detection of marker on the optical device and executing the positioning of the light receiving element with a high accuracy, the space region resulting from eliminating a part of the light absorbing layer that absorbs the detection light of the light receiving element, the transmission amount of the detection light toward the marker detecting region that is parallel to a primary plane being equal to 30% or higher, the detection light having penetrated and transmitted the primary plane of the light receiving element.

Semiconductor photodetector and optical transmitting device

Burying type avalanche photodiode and fabrication method thereof

Optical module

An optical assembly structure includes, a semiconductor element generating a large amount of heat and a high impedance optical element which are to be mounted, with low optical loss on the same semiconductor substrate which has an optical waveguide formed thereon.The element generating a large amount of heat is mounted on a terrace of the semiconductor substrate directly or through an insulating layer having a thickness of submicron order, while the high impedance element is mounted in a groove which is etched into the semiconductor substrate to such an extent that the optical axis of the high impedance element mates with the optical axis of the optical waveguide layer formed on a recess in the semiconductor substrate. The optical axes can be adjusted independently for the respective elements. Alternatively, with a potential on the semiconductor substrate set equal to a supply voltage or a ground potential, a crystal substrate for a forward biased heat generating element is given the polarity opposite to that of a crystal substrate for a reverse biased element which may imply a problem of stray capacitance.

Hybrid optical integration assembly using optical platform

An optical fiber is held in a ferrule, and then the ferrule is located in a positioning groove formed in a substrate, thereby aligning the optical fiber with an optical device bonded to a surface of the substrate. Then, a lid is placed on the substrate in such a manner that the ferrule is located in a positioning groove formed in the lid and that the optical device is received in a cavity formed in the lid. The ferrule is thus held between the two grooves, and in this condition a resin is filled in the two grooves, thereby retaining the ferrule. Then, the lid is sealingly secured to the substrate. After these parts are thus assembled together, this assembly is put in dies, and then a package is molded.

Resin molded optical assembly

An optical routing system where a time-division multiplexing signal train passes through a front stage semiconductor laser amplifier and detects information of a header and is multiplexed with a local oscillator light from a variable wavelength light source and passes through a rear stage semiconductor laser amplifier, and then is demultiplexed by an optical wavelength division demultiplexer and is outputted to an output side optical signal transmission fiber and an intermediate output port. Wavelength of the local oscillator light and selective wavelength of the optical wavelength division demultiplexer are selected so that a packet is outputted to an assigned intermediate output port. Thereby for the time-division multiplexing optical signal train, while the optical signal train as a whole is held, a specified part or a packet can be distributed.

Optical routing system

A method of fabricating diffraction gratings wherein a photomask is arranged on a substrate which is coated with a photoresist, light is to be incident thereupon at an acute angle relative to the normal direction of the photomask, and a bright/dark pattern is formed on said photoresist by the interference of the transmission light that has passed through the photomask and the diffraction light. The invention further deals with a photomask used for the above method.

Optical device diffraction gratings and a photomask for use in the same

Growing community of inventors

Hidaka, Japan

Shinji Tsuji