Sanyo Electric Co., Ltd.

Sumitomo Electric Industries, Limited

Sumitomo Electric Device Innovations, Inc.

Tokyo Ohka Kogyo Co., Ltd.

Tsutomu Ishikawa

Ryuichi Ogawa

Masashi Arai

Hirokazu Tanaka

Kazuhisa Ishiguro

Masaya Tanno

Kanji Tanaka

Noboru Usui

Naoya Kono

Muneo Nakayama

Toshihiro Nishimura

Masao Shibata

Hiroshi Inoguchi

Masato Onaya

Satoru Sekiguchi

Hajime Tanaka

Hiroshi Kobori

Kiyoshi Takada

Fumio Tosaka

Toshimitsu Kaneko

Akira Hashimoto

Susumu Yamada

Akira Tsukihashi

Isao Ochiai

Masataka Watanabe

Hiroshi Kojima

Hirofumi Okada

Naobumi Nagasawa

Osamu Ikeda

Hideo Imaizumi

Toshiyuki Take

Kiyokazu Kamado

Hiroki Seyama

Akira Kabashima

Takayuki Imaida

Toyotoshi Machida

Hideo Kunio

Hideo Kunii

A method for manufacturing an optical modulator is disclosed. The optical modulator includes a Mach-Zehnder modulator, the Mach-Zehnder modulator including an electrode and an arm waveguide, the electrode being provided on the arm waveguide. The method includes a step of preparing the Mach-Zehnder modulator, a step of acquiring a relationship between a voltage applied to the electrode and a phase change amount of light propagating through the arm waveguide based on a light transmittance in the arm waveguide, a step of acquiring a voltage in which a range of a phase change amount of light in the Mach-Zehnder modulator has a predetermined range based on the relationship, and a step of storing the voltage in a storage unit.

Method for manufacturing optical modulator, testing method, non-transitory storage medium, and light transmission apparatus

A method for manufacturing an optical modulator is disclosed. The method includes a step of preparing a Mach-Zehnder modulator, a step of acquiring, based on a light transmittance in an arm waveguide, a relationship between a voltage applied to an electrode and a phase change amount of light propagating through the arm waveguide, a step of acquiring, based on the relationship, a voltage in which the phase change amount of the light propagating through the arm waveguide has a predetermined when the light is modulated, and a step of storing the voltage in a storage unit.

An optical transmitter includes a Mach-Zehnder modulator having an arm waveguide and a phase controller configured to control a phase of a light propagating through the arm waveguide by applying a voltage to the Mach-Zehnder modulator. When the voltage is deviated from a predetermined range, the phase controller shifts the voltage in the direction opposite to a direction of the deviation from the predetermined range by the amount corresponding to a change of 2&#x3c0; in the phase.

Optical transmitter, method for controlling the same, and non-transitory computer-readable medium

An optical modulator includes a waveguide formed of a semiconductor and configured to allow light to propagate therethrough; a first electrode disposed on the waveguide and electrically connected to the waveguide; and a second electrode separated from the waveguide and electrically connected to the waveguide. An edge of the second electrode on a light entry side is located downstream of an edge of the first electrode on the light entry side in a propagation direction of the light.

Optical modulator

An optical modulator includes: a waveguide made of semiconductor, a light being input to one of ends of the waveguide; and a first electrode provided on the waveguide and overlapping with a part of the waveguide, wherein the waveguide has a first region to a third region along a propagation direction of the light from the one of ends, wherein neither the first region nor a part of the second region on a side of the first region in the propagation direction overlaps with the first electrode, wherein the third region and a part of the second region on a side of the third region in the propagation direction overlap with the first electrode, wherein a second width of the second region is larger than a first width of the first region and a third width of the third region.

A method to control a wavelength tunable laser diode (tunable LD) is disclosed. The tunable LD includes a SG-DFB region and a CSG-DBR region to tune the emission wavelength thereof. The CSG-DBR region includes three segments, where the refractive indices of respective segments are variable by heaters provided therein. When the electrical power supplied to two segments is optionally selected, the power supplied to the rest segment is corrected by an offset from a value reflecting physical dimensions of the heaters. The offset is determined such that the tunable LD shows the best side mode suppression ratio (SMSR).

Method to determine operating conditions of wavelength tunable laser diode and to control optical transmitter providing wavelength tunable laser diode

A semiconductor laser includes: a first reflector that is provided in a gain region and has a sampled grating in which a plurality of segments are combined; and a second reflector that is optically connected to the first reflector and has a sampled grating in which a plurality of segments are combined, the plurality of segments of the first reflector having a short-segment region and a long-segment region, the long-segment region having an optical length that is larger than that of the short-segment region and being positioned closer to the second reflector than at least one of the short-segment region, the optical length of the long-segment region being larger than that of the short-segment region in a range of integral multiple (n&#x2267;1) plus-minus 25% of the optical length of the short-segment.

Semiconductor laser

A method for tuning a semiconductor laser including a plurality of wavelength selection portions, each of which has a periodic wavelength characteristic, including: controlling a value of a refractive index controlling means of the wavelength selection portions to achieve a desired output wavelength of the laser; and shifting the value when the value is equal to or excess of a predetermined value to a basal value side until achieving the desired output wavelength, the basal value being a value without applying refractive index variation by the refractive index controlling means, the predetermined value being a value for shifting one period of the periodic wavelength characteristic.

Method for tuning semiconductor laser

A method of controlling a wavelength-tunable laser selecting an oscillation wavelength with a combination of a plurality of wavelength selection portions of which wavelength peak is different from each other, comprising: a first step of confirming a control direction of the wavelength selection portion in a case where a setting value is changed from a first setting value for achieving the first wavelength to a second setting value for achieving the second wavelength; a second step of setting a setting value that is shifted from the second setting value in a direction that is opposite of a pre-determined changing direction on the wavelength selection portion as a prepared setting value, when the control direction confirmed in the first step is opposite to the pre-determined changing direction; and a third step of changing the prepared setting value set in the second step to the second setting value.

Method of controlling wavelength-tunable laser

An integrated semiconductor device is provided that has pads with less input signal attenuation. When J-FET ( ) is driven by an input signal, the current passing through it varies. The parasitic capacitance ( ) is charged or discharged by the input/output signal of the buffer circuit ( ) following the varying current. Thus, since the voltage across the parasitic capacitance ( ) varies in phase and at the same level, the parasitic capacitance ( ) can be ignored. This effect allows attenuation of an input signal due to the parasitic capacitance ( ) to be prevented.

Semiconductor integrated circuit having pads with less input signal attenuation

In a data transmission, a driving circuit 14 drives a light receiving element 15 in accordance with data from an external control circuit. In accordance with IrDA or remote control communication, driving capability of the driving circuit is changed. In a data reception, received data is transferred to a first or a second signal processing circuit in accordance with the IrDA or remote control communication and processed according to each communication format. In this configuration, a single light emitting or light receiving element permits data communication in different kinds of data communication formats.

Optical semiconductor device

A mold,for molding semiconductor chips,and,serving as a light emitting element and a light receiving element, respectively, is made of a material capable of transmitting light. A groove,is formed on the region where light is emitted from and incident on the semiconductor chips so that it constitutes a reflecting face. Thus, the light is emitted and incident through the side E of the mold. In this configuration, the outer size of the light receiving element or light emitting element can be minimized, and the module provided with these semiconductor chips can also be miniaturized.

Optical semiconductor device and optical semiconductor module equipped with the same

In a CD type disk player, main data in a digital signal, which is read from a CD type disk traced by a pickup, is decoded in a decoding means in accordance with a bit clock regenerated in a clock regenerator. Both the writing and reading of the data into and from a memory can be synchronized with the bit clock. Also, a selector can switch over the operation clock of the decoding means, thereby selecting the more important factor, either time base precision or decoding ability, in correspondence with the kind of disk. While avoiding the enlargement in size and power consumption of the disk motor, the read out of the information from the disk can be conducted at a higher speed.

Signal processing circuit for an optical disk player including data

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Yokohama, Japan

Tsutomu Ishikawa