Mitsubishi Electric Corporation

Eisuke Haraguchi

Toshiyuki Ando

Shumpei Kameyama

Jiro Suzuki

Hitomi Ono

Junya Nishioka

Hiroshi Nishimoto

Takayuki Yanagisawa

Keisuke Matsuda

Nobuki Kotake

Takashi Nishitani

Yutaka Kajiyama

Akihiro Fujie

Mana Hosokawa

A laser radar device performs control to make a focus distance of transmission light equal to a measurement distance by switching a plurality of laser light sources that emit beams of oscillation light having wavelengths different from each other to switch emission directions of the transmission light while maintaining the focus position of optical antennas, and changing the wavelength of the beams of oscillation light according to the measurement distance.

Laser radar device

An optical transmission unit () transmits an optical signal having a light intensity set as a Low level component of a pulse. An optical partial reflector () is provided on a path through which transmission light is transmitted from a circulator () to the atmosphere, and reflects the optical signal. A detection unit () performs coherent detection on reception light using, as local light, a signal in a Low level section in the optical signal reflected by the optical partial reflector ().

A laser device includes element circuits, a front optical system, and a reflective optical system. The front optical system forms a plurality of light beams by collimating a plurality of phase modulated light signals input from the element circuits, and generate a plurality of partially reflected light signals by partially reflecting the plurality of phase modulated light signals. The reflective optical system multiplexes the input local oscillation light with the plurality of partially reflected light signals by reflecting the local oscillation light in a direction of the front optical system. The element circuits can convert each of a plurality of interference light signals generated by multiplexing of the plurality of partially reflected light signals and the local oscillation light into a plurality of electric signals, and can detect a phase error between the plurality of electric signals and a reference signal.

Laser device

A laser radar device includes: a modulator () for causing a transmission seed light beam to branch, and giving different offset frequencies to a plurality of the transmission seed light beams having branched, and then modulating the plurality of transmission seed light beams into pulsed light beams and outputting the pulsed light beams, or for modulating the transmission seed light beam into a pulsed light beam, causing the pulsed light beam to branch, and giving the different offset frequencies to a plurality of the pulsed light beams having branched, and then outputting the plurality of pulsed light beams; a band pass filter () in which a frequency band including frequencies of signal components included in a plurality of beat signals detected by an optical heterodyne receiver () is set as a pass band and a frequency band not including the frequencies of the signal components is set as a cutoff band; and an ADC () for sampling the beat signals passing through the band pass filter () at a sampling frequency.

An optical control type phased array antenna includes: a plurality of antenna elements; a multi-wavelength light source; an optical demultiplexing circuit for separating a plurality of optical signals and local oscillation light from output light of the multi-wavelength light source; optical modulators for generating a plurality of modulated optical signals by modulating the plurality of optical signals with the output signals of the plurality of antenna elements; an optical coupler for multiplexing the plurality of modulated optical signals and the local oscillation light to generate multiplexed light and dividing the multiplexed light into reception optical signals of a plurality of channels; and an optical dispersion compensation circuit for compensating for a phase difference between the plurality of modulated optical signals by performing dispersion compensation on the reception optical signals, respectively.

Optical control type phased array antenna

A laser radar system according to the present invention includes: a light source to output light having a first frequency in a first period and light having a second frequency in a second period; an optical splitter to split the lights, outputted from the light source, into signal light and local oscillator light; an optical modulator to modulate the signal light into pulsed light; an optical antenna to output the pulsed light into space and to receive, as reception light, the scattered light from a target; an optical heterodyne receiver to perform heterodyne detection on the reception light by using the local oscillator light; and a measurement unit to measure the distance to the target or the movement characteristics of the target by using the reception signal detected by the optical heterodyne receiver, wherein the optical heterodyne receiver performs the heterodyne detection on the first frequency of the reception light by using the second frequency of the local oscillator light. With this configuration, a large amount of frequency shift can be provided between the signal light and the local oscillator light, and thus, the distance to the target can be measured with high resolution by using short pulsed-light.

Laser radar system

There includes: an optical splitter splitting modulated light into local oscillator light and signal light beams; a phase adjustment unit adjusting phases of signal light beams; an optical amplification unit amplifying signal light beams phase-adjusted; an optical phased array antenna outputting signal light beams amplified to space; a phase control unit synchronizing with a reference signal light beams, output from the optical phased array antenna and multiplexed with the local oscillator light; an acquisition and tracking mechanism adjusting output angles of signal light beams; an angle detection unit detecting arrival angles of received light; and a control unit setting the reference signal to first reference signals having different frequencies, supplementing the received light based on a detection result, setting the reference signal to second reference signals having equal frequencies, and tracking the received light based on the detection result.

Free-space optical communication apparatus

A laser radar device includes: a wavelength-tunable light source; an optical branch coupler dividing light emitted by the wavelength-tunable light source into local and transmission light; an optical phase modulator applying, to the transmission or local light, frequency shifts for wavelength discrimination of different shift amounts corresponding to respective wavelengths of light emitted by the wavelength-tunable light source; a wavelength separator switching between light paths for output, in response to wavelength of transmission light; an optical antenna emitting into space transmission light output by the wavelength separator, and receiving, as received light, backward-scattered light generated from transmission light in space in which lines of sight corresponding to respective wavelengths of the transmission light are determined; an optical heterodyne receiver receiving local light and received light, and performing heterodyne detection; and a signal processor performing frequency analysis of the optical heterodyne receiver output signal.

An optical transmission device includes: a controlled oscillator for outputting a calibration signal having an output frequency that corresponds to an input oscillation control signal; an electrical-to-optical conversion circuit for generating an optical transmission signal by superimposing a transmission signal in a radio frequency band and the calibration signal on an optical wave; an optical input and output unit for sending the optical transmission signal to an optical transmission path and receiving a reflection signal that is a part of the optical transmission signal from an optical reception device; an optical-to-electrical converter for converting the reflection signal into a radio frequency signal; a phase locked loop for generating the oscillation control signal so that radio frequency output of the optical-to-electrical converter is phase-locked with a reference signal input from a reference signal source; and a signal generation circuit for generating, as the transmission signal, the radio frequency signal phase-locked with the calibration signal.

Optical transmission device and optical transmission system

A base station apparatus includes a ground station device and a plurality of ground antenna devices coupled to the ground station device via an optical transmission path. The ground station device performs electrical-optical conversion on an analog electrical signal to be transmitted to a mobile station and a reference clock signal to generate optical signals, performs wavelength division multiplexing on the obtained optical signals to generate a multiplexed optical signal, and outputs the multiplexed optical signal to the optical transmission path. Each of the plurality of ground antenna devices demultiplexes the multiplexed optical signal input from the optical transmission path into demultiplexed optical signals, performs optical-electrical conversion on the demultiplexed optical signals to generate electrical signals, up-converts a frequency of the analog electrical signal obtained through the optical-electrical conversion based on the reference clock signal obtained through the optical-electrical conversion to generate an up-converted signal, and transmits the up-converted signal to the mobile station.

Base station apparatus, ground station device, and ground antenna device

A configuration is provided which includes: a reference light source to emit laser light; an optical phase modulator to perform phase modulation of transmission light of the laser light on the basis of a linear-phase-modulation signal having a first frequency component and a second frequency component; an optical intensity modulator to modulate light intensity of the transmission light on the basis of a pulsed light generation signal for generation of pulsed light; first and second optical antennas to emit the transmission light to a space and receive reflected light from a first point and a second point; an optical receiver to perform heterodyne detection on light obtained by mixing received light and local oscillation light; and a signal processor to separate a received signal on the basis of the first and the second frequency components.

Laser radar device and wind turbine control system

An optical transmitterincludes an optical phase modulatorthat performs phase modulation on a continuously oscillating light, a light intensity modulatorthat performs pulse modulation on the light on which the phase modulation is performed, to output the light as a transmission light, a first signal generatorthat generates a pulse modulation driving signal in which on and off time intervals are repeated periodically, to drive the optical intensity modulator, and a second signal generatorthat generates a saw tooth wave driving signal having an amplitude equal to an integral multiple of a driving voltage needed to acquire a modulation phase of 2&#x3c0; of the optical phase modulator, and having a constant period, to drive the optical phase modulator

An optical frequency control device includes a light source for emitting light, a sawtooth wave generator for generating a sawtooth wave, a frequency controller for controlling the frequency of the sawtooth wave, and an optical phase modulator driven by the sawtooth wave for carrying out phase modulation of the light.

Growing community of inventors

Tokyo, Japan

Eisuke Haraguchi