Mitsubishi Electric Corporation

Kyoto University

Kentaro Enoki

Koichi Akiyama

Shimpei Ogawa

Shusaku Hayashi

Daisuke Fujisawa

Kosuke Shinohara

Eiji Yagyu

Yasuhisa Shimakura

Hiroaki Shintaku

Satoshi Nishikawa

Susumu Noda

Toshiyuki Tanaka

Tsuyoshi Yoshida

Wataru Kunishi

Menaka De Zoysa

Yohei Hokama

Yuichiro Horiguchi

Kenji Ishizaki

A two-dimensional photonic-crystal laser includes: a substrate made of an n-type semiconductor; a p-type cladding layer on an upper side of the substrate made of a p-type semiconductor; an active layer on an upper side of the cladding layer; a two-dimensional photonic-crystal layer on an upper side of the active layer including a plate-shaped base body made of an n-type semiconductor wherein modified refractive index areas whose refractive index differs from the base body are arranged; a first tunnel layer between the substrate and cladding layer made of an n-type semiconductor having a carrier density higher than the substrate's; a second tunnel layer between the first tunnel and cladding layers, made of a p-type semiconductor having a carrier density higher than the p-type semiconductor layer's; a first electrode on a lower side of or in the substrate; and a second electrode on an upper side of the two-dimensional photonic-crystal layer.

Two-dimensional photonic-crystal laser

A biological material measuring apparatus includes an infrared light source unit to radiate infrared light in entirety or part of a wavelength region including absorption wavelengths of a biological material, a prism to cause the infrared light radiated from the infrared light source unit to pass therethrough and emit the infrared light to a living body surface while being in contact with the living body surface, a light source to radiate light of a wavelength in a visible light region or a near infrared region to the prism, and a light position detector to detect a path of light from the light source by detecting light from the light source which is emitted from the prism.

Biological material measuring apparatus

A controller corrects a spectrum S (&#x3bb;) detected at a wavelength &#x3bb; of signal light to S' (&#x3bb;) in accordance with expressions below: I(&#x3bb;)=(I&#x2212;I)&#xd7;(&#x3bb;&#x2212;&#x3bb;)/(&#x3bb;)&#x2212;I, and S&#x2032;(&#x3bb;)=S(&#x3bb;)&#x2212;I(&#x3bb;), where Iis the intensity of infrared light detected at a wavelength &#x3bb;of reference light and Iis the intensity of infrared light detected at a wavelength &#x3bb;of correction light.

An infrared light source radiates infrared light. An ATR prism receives, on a first end face, the infrared light radiated from the infrared light source, causes the received infrared light to pass therethrough while repeating total reflection off a second end face and a third end face, and emits the infrared light that has passed therethrough from the third end face. An infrared photodetector detects the intensity of the infrared light emitted from the ATR prism. Strain sensors, which are contact sensors of one type, are attached to the ATR prism and configured to detect a contact state between the ATR prism and a measurement skin.

An infrared light source radiates, to an ATR prism, infrared light in entirety or part of a wavelength range with absorption wavelengths of a biological material. The ATR prism is adherable to a measurement skin. A prism vibration controller is mounted on the ATR prism and vibrates the ATR prism perpendicular to a contact surface between the ATR prism and the measurement skin. A controller causes an infrared photodetector to detect infrared light in synchronization with the vibration of the ATR prism.

Biological material measuring apparatus and method of measuring biological material

An optical modulation apparatus that can adjust modulation timing. A timing adjuster adjusts the modulation timing on the basis of an intensity detected by a light intensity detector, after a data generator respectively generates, as a first data signal and a second data signal, a first test data signal and a second test data signal each having a data string containing a test pattern in which a plurality of continuous marks and a plurality of continuous spaces are alternately repeated, and after a phase adjuster adjusts a phase difference to zero or &#x3c0;.

Optical modulation apparatus, and timing adjustment method for optical modulation apparatus

A superposition circuitry superposes a dither signal on a reference DC bias voltage and outputs a resultant voltage as a bias voltage to an MZ modulator, during control of a driving voltage amplitude. During the control of the driving voltage amplitude to the MZ modulator, an amplitude setter determines, by varying the amplitude of an output voltage from an amplifier, a plurality of amplitudes of output curves from a synchronous detector, each of which is obtained by varying the reference DC bias voltage output from a bias controller, and the amplitude setter sets the amplification factor of the amplifier, based on an amplitude of the output voltage from the amplifier that corresponds to an amplitude satisfying a predetermined condition, out of the plurality of the amplitudes of the output curves from the synchronous detector.

Optical modulation device and method for controlling optical modulation device

A timing adjuster shifts a timing between a first data-stream group and a second data-stream group in accordance with a timing setting. A data generator in first test mode generates a first test-data stream repeating 2N-bit marks and 2N-bit spaces as each of a first data stream and a third data stream, and generates a second test-data stream that is N-bit shifted from the first test-data stream, where N denotes a natural number. A first phase-difference setting and a second phase-difference setting are rendered zero. The timing adjuster adjusts the timing setting so as to maximize a detected value from a peak detection circuit.

Optical modulation unit, and method for controlling optical modulation unit

An optical transmitter includes an optical modulator configured to modulate input light and output a light signal, a drive unit configured to output a modulation data signal to the optical modulator, and a bias controller configured to perform feedback control of bias voltage applied to the optical modulator. During a modulation OFF operation of the optical modulator, the bias controller switches a control target point from a first control target point to a second control target point and executes the feedback control.

Optical Transmitter

An optical modulator element includes first and second optical modulators, an optical input terminal, and a branch coupler. Each of the first and second optical modulators includes a pair of Mach-Zehnder waveguides, a first optical coupler to split rays from the branch coupler into the pair of Mach-Zehnder waveguides, and a second optical coupler to combine rays transmitted through the pair of Mach-Zehnder waveguides. The first and second optical modulators are disposed in such a manner that a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the first optical modulator and a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the second optical modulator are angled toward each other.

Optical modulator element, optical modulation module including optical modulator element, and method for manufacturing optical modulator element

An optical modulation unit included in an optical transmitter includes two optical modulators that modulate each of two light beams based on applied bias voltages and input modulation signals, and an optical phase regulator that is connected to either of the two optical modulators, and regulates a phase of the light beam incident on the optical modulator. In a state where no modulation signal is input to the two optical modulators, while keeping bias voltages to be applied to one optical modulator and the optical phase regulator constant, the controller determines a first initial bias voltage such that an output light beam from the other optical modulator becomes zero. Thereafter, the controller determines a second initial bias voltage such that an output light beam from the one optical modulator becomes zero, while applying the first initial bias voltage to the other optical modulator.

Growing community of inventors

Chiyoda-ku, Japan

Kentaro Enoki