Opnext Japan, Inc.

Hitachi, Ltd.

Oclaro Japan, Inc.

Naohiko Baba

Yasuhiro Yamada

Norio Chujo

Yoshihiko Hayashi

Tomonao Kikuchi

Mitsuo Akashi

Akio Osaki

Akihiro Hayami

Hiroshi Yamamoto

Kimio Tatsuno

Kazuo Yamaguchi

Tatemi Ido

Kazumi Kawamoto

Kazuhiro Komatsu

Shigeru Tokita

Hideyuki Kuwano

Michihide Sasada

Kazuo Aoyama

Tadashi Hatano

Hideaki Asakura

Yasunori Iwafuji

Hideyuki Serizawa

Atsushi Murata

Yoshikuni Uchida

Yoichi Honzawa

Hiroki Irie

Takashi Minato

Tsutomu Yoshiya

Hideki Satoh

Shinzoo Nishiyama

Kyouichi Yamamoto

To provide an optical module and a method for aligning the optical module with which alignment can be easily performed. An optical module includes first optical element sections and a second optical element section optically joined to the first optical element sections. Each first optical element section includes an optical conversion element, a ferrule having a distal end being in contact with and optically joined to the second optical element section, and a first optical system disposed in a position where the ferrule and the optical conversion element are optically adjusted. The second optical element section includes joining sections in contact with and joined to, in joining parts, the distal ends of the ferrules, a wavelength multiplexing optical element optically joined to the optical conversion elements, and second optical systems respectively disposed in positions where the wavelength multiplexing optical elements and the joining parts are optically adjusted.

Optical module and method for aligning optical module

A base material includes a pair of end regions located on both sides in a first direction, and an intermediate region located between the pair of end regions. The intermediate region includes a pair of side edges on both sides in a second direction orthogonal to the first direction. Both the pair of side edges do not project outward in the second direction from the pair of end regions. At least one of the pair of side edges has a shape recessed inward in the second direction from the pair of end regions. Terminals include end pads and a side pad. The end pads are located in each of the pair of end regions of the base material and arranged in the second direction. The side pad is located at at least one of the pair of side edges of the base material.

Optical module and flexible printed circuit board

An object of disclosed technology is to control lasing wavelengths so that a wavelength shift does not occurs. Another object is to permit wavelengths of a light source for wavelength division multiplexing optical-fiber communication system to be variable in response to an ITU-TS grid. A means for achieving the objects is as follows: locating an etalon in a light path of diode laser light, which is a parallel plane wave changed by a collimator lens; generating a wavelength error signal from a difference between both of divided pieces of light from transmitted light or reflected light; and locking a wavelength of a diode laser device according to the wavelength error signal.

Optical fiber communication equipment and its applied optical systems

An optical transmission system includes a current source for outputting a drive current, a semiconductor laser for converting the drive current into a stimulated emission light and producing the same, a drive circuit for converting a transmission data signal into a modulation control signal and outputting the same, an optical modulator for receiving the stimulated emission light and a shading control signal for interrupting light emission and producing and outputting transmission signal light by changing an amount of transmission of the stimulated emission light according to the shading control signal, and a shading element for receiving the transmission signal light and a shading control signal for interrupting light emission and interrupting the transmission of the transmission signal light according to the shading control signal whereby an optical signal having wrong optical wavelength is rapidly prevented.

Optical transmission device and optical transmission system using the same

A driver circuit comprises a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply. Different electric potentials are applied to the bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about 1/100 or smaller. An amplitude of an output current is controlled by the higher of the electric potentials applied to the base of one of the first transistors.

Driver circuit and optical-transmission module

A method of manufacturing an optic transmission module assures a high reliability for the module by inspecting the character of a low bit error rate (BER) of the module quickly and accurately. The module is employed in an optical communication system (light transmission system) required to cope with information communication systems that are becoming faster and faster in operation and larger and larger in capacity. Also disclosed is a system and a method for inspection of the BER character which uses a rectangular wave pulse as an interference light to calculate a degradation quantity of a signal-to-noise ratio (S/N) on the basis of a simple theory, thereby inspecting the BER character by extrapolating a case in which there is no interference light (S/X&equals;&infin; or X&equals;0) with use of a sign error rate theoretical value according to a bit error rate of a light signal measured according to the degradation quantity.

Method for manufacturing optic transmission modules and system for inspecting bit error rate characters

A driver circuit comprises a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply. Different electric potentials are applied to the bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about {fraction (1/100)} or smaller. An amplitude of an output current is controlled by the higher of the electric potentials applied to the base of one of the first transistors.

Two sets of a high speed differential amplifier and a low speed differential amplifier are prepared, and frequency response speeds of these high speed/low speed differential amplifiers are different from each other. Both an oscillating frequency and a frequency modulation sensitivity of a ring oscillator type voltage-controlled oscillator circuit can be separately set by adding two outputs of these differential amplifiers to each other and by varying the selection ratio of these high speed/low speed differential amplifiers in a linear manner. Thus, the setting ranges for the oscillating frequency and the frequency modulation sensitivity are enlarged. At this time, since a summation of currents flowing through the high speed/low speed differential amplifiers is continuously made constant, the oscillating frequency depending characteristic of the output amplitude of the VCO circuit can be canceled. Furthermore, since control signals are supplied in a differential structure, increasing of jitter components caused by the common mode noise can be suppressed.

Optical receiver module optical transmitter module phase-locked loop circuit voltage-controlled oscillator and frequency response controllable amplifier

An optical transmitter includes a plurality of optical wavelength stability control apparatuses, each of which is capable of compensating for a wavelength drift by varying a laser diode drive current. Each of the optical wavelength stability control apparatuses detects a laser diode drive current, which is controlled by an auto power control circuit, by using a laser diode drive current detector. The laser diode drive current is normalized by a laser diode drive current increase/decrease normalization unit. A laser diode temperature control target value is generated at a compensated reference voltage generator, in response to the normalized laser diode drive current, to control a current value applied to a thermoelectric cooler so that an output value of a temperature monitor circuit approaches a predetermined laser diode temperature control target value.

Optical wavelength stability control apparatus, optical transmitter and multiple wavelength transmitter

Growing community of inventors

Fujisawa, Japan

Naohiko Baba