Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Satoshi Kajiya

Takashi Mizuochi

Katsuhiro Shimizu

Yukio Kobayashi

Takahiko Itoh

Kaoru Kinjo

Satoshi Nishikawa

Eitaro Ishimura

Keisuke Matsumoto

Kazuyuki Ishida

Toshiyuki Tokura

Tetsuhiro Fukao

Taichi Kogure

A semiconductor optical integrated device comprises a semiconductor amplifier and a plurality of semiconductor lasers, wherein the semiconductor amplifier and the semiconductor lasers are monolithically integrated on a semiconductor substrate, an n-side cladding layer of the semiconductor amplifier and an n-side cladding layer of each of the semiconductor lasers are electrically insulated by an insulating layer formed between the semiconductor substrate and the n-side cladding layer of the semiconductor lasers and an insulating layer formed between the n-side cladding layer of the semiconductor amplifier and the n-side cladding layer of the semiconductor lasers, the n-side cladding layer of the semiconductor lasers and the p-side cladding layer of the semiconductor amplifier is configured to be electrically connected, and the semiconductor amplifier and each semiconductor laser of the plurality of semiconductor lasers are electrically connected in series.

Semiconductor optical integrated device

A laser module includes a light source device having a first amplifier that outputs first output light, and a second amplifier that outputs second output light, a first drive circuit that supplies the first amplifier with a first drive current, a second drive circuit that supplies the second amplifier with a second drive current. A dither signal is superimposed on one of two drive currents to respectively grasp the characteristics of the two amplifiers.

Dual wavelength laser module with constant output intensity

Two signal lights having different wavelengths are bidirectionally transmitted on an optical-fiber transmission-line. A Raman pump light source generates a first Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the first signal light and without response to the second signal light. Another Raman pump light source generates a second Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the second signal light and without response to the first signal light. The first Raman pump light and the second Raman pump light are differently injected from respective input/output terminals into the optical-fiber transmission-line by optical combining and branching filters.

Method of and device for performing bi-directional transmission using a single-wire

The optical transmission apparatus has a Mach-Zehnder optical modulator, a light source for applying an optical signal of a continuous light to the optical modulator, a driving circuit for inputting a driving signal into the optical modulator, a branching filter for taking out a part of an output optical signal, a photodiode for converting the taken-out output optical signal into an electric signal, a band pass filter for extracting a frequency component of a driving signal included in this electric signal, an error signal generator circuit for generating an error signal of a bias voltage that minimizes a value of the extracted frequency component, and a bias voltage control circuit for applying a bias voltage added with this error signal to the optical modulator.

Optical transmission apparatus and bias voltage control method for the optical modulator

An optical fiber propagates and amplifies a second signal light that is a wavelength-multiplexed signal of a first signal light of a plurality of wavelengths and a reference light that is out of a wavelength range of amplification. An excitation light source outputs an excitation light for amplifying the second signal light. A beam splitter splits a portion of the second signal light into the first signal light and the reference light. A signal light level detecting unit detects a level of the first signal light. A reference light level detecting unit detects a level of the reference light. A signal level setting unit calculates a target value for constantly maintaining a Raman gain, and controls the output level of the excitation light in such a way that the first signal level matches with the target value.

Raman amplifier and optical relay transmission system

The optical amplifier apparatus comprises an optical amplifier () which amplifies an input signal light, an output detecting unit () which detects an output level of the optical amplifier, an output control unit () which controls an output level of the optical amplifier according to an output level detected by the output detecting unit (), a gain inclination detecting unit () which detects a gain inclination relating to a wavelength of the optical amplifier, and a gain inclination control unit () which controls a gain inclination of the optical amplifier () according to a gain inclination detected by the gain inclination detecting unit ().

Optical amplifier device

The optical amplifier apparatus comprises an optical amplifier which amplifies an input signal light, an output detecting unit which detects an output level of the optical amplifier, an output control unit which controls an output level of the optical amplifier according to an output level detected by the output detecting unit, a gain inclination detecting unit which detects a gain inclination relating to a wavelength of the optical amplifier, and a gain inclination control unit which controls a gain inclination of the optical amplifier according to a gain inclination detected by the gain inclination detecting unit.

Optical amplifier apparatus

An optical repeater is provided between a first optical fiber transmission path and a second optical fiber transmission path having a zero-dispersion wavelength different from the first optical fiber transmission path. This optical repeater wave-converts a wavelength division multiplex signal input from the first optical fiber transmission path with respect to respective wavelengths thereof, and outputs the wave-converted signal to the second optical fiber transmission path.

Optical wavelength division multiplexing transmission suppressing four-wave mixing and SPM-GVD effects

In a one-fiber bidirectional optical transmission system in which output optical signals of optical transmitter-receivers respectively connected to the opposite ends of one optical fiber transmission line are bidirectionally transmitted in the optical fiber transmission line, which utilizes a Raman amplification effect by backward pumping, a frequency satisfying the conditions of |f&#x2212;f|&#x2260;|f&#x2212;f| and |f&#x2212;f|&#x2260;|f&#x2212;f| is selected, where fis a zero dispersion frequency of the optical fiber transmission line, fand fare the frequencies of the first signal and the second signal, respectively, and fand fare frequencies of the first Raman pump light and the second Raman pump light, respectively.

Growing community of inventors

Tokyo, Japan

Satoshi Kajiya