Abstract: An optical measurement device includes at least a multi-frequency laser configured to simultaneously generate a frequency-fixed carrier and at least one frequency-modulated subcarrier, an optical branching element, a dual frequency beat signal generator, a difference signal generator, and an arithmetic processing unit. Either the carrier or the subcarrier within the output light of the multi-frequency laser is used as first measurement light and either the carrier or the subcarrier having a frequency different from that of the first measurement light is used as second measurement light. The dual frequency beat signal generator separates and outputs a first complex beat signal derived from the first measurement light and a second complex beat signal derived from the second measurement light. The difference signal generator outputs a difference signal between the first complex beat signal and the second complex beat signal.

Abstract: An optical measurement device and an optical measurement method that can accurately measure a distance and a velocity by removing an influence of a nonlinear chirp of a laser in FMCW LiDAR. The optical measurement device includes a laser that outputs light of which a frequency is modulated; a photodetector; a heterodyne optical system that splits output light of the laser into two components, uses one as probe light, uses the other as reference light, adds a frequency shift to one of the probe light and the reference light, applies the probe light to an object, combines scattered light from the object and the reference light, and causes the combined light to be incident on the photodetector; an IQ detector; and an arithmetic operation processor.

Abstract: An apparatus and a method which enable, in optical angle modulation, measurement of laser light, to measure by a delayed self-heterodyne method, accurate measurement of a temporal waveform of optical angle modulation, without any influence by light intensity modulation, without necessity of for calibration, and without necessity for stabilizing an interferometer. In an optical angle modulation measurement apparatus using a delayed self-heterodyne method, a heterodyne interferometer that is fed with laser light to be measured; a photodetector that receives output light of the heterodyne interferometer and performs heterodyne detection of the output light to output a beat signal; using a phase demodulator that is configured to demodulate a phase of a beat signal; and a temporal waveform analyzer that is configured to obtain a temporal waveform of optical angle modulation, from the phase of the beat signal.

Abstract: An apparatus and a method which enable, in optical angle modulation, measurement of laser light, to measure by a delayed self-heterodyne method, accurate measurement of a temporal waveform of optical angle modulation, without any influence by light intensity modulation, without necessity of for calibration, and without necessity for stabilizing an interferometer. In an optical angle modulation measurement apparatus using a delayed self-heterodyne method, a heterodyne interferometer that is fed with laser light to be measured; a photodetector that receives output light of the heterodyne interferometer and performs heterodyne detection of the output light to output a beat signal; using a phase demodulator that is configured to demodulate a phase of a beat signal; and a temporal waveform analyzer that is configured to obtain a temporal waveform of optical angle modulation, from the phase of the beat signal.

Abstract: An optical gate switch circuit includes: an asymmetric Mach-Zehnder interferometer having an optical path that outputs control light and probe light to a second optical directional coupler via a first optical directional coupler and an optical phase modulation element, and another optical path that connects a third optical directional coupler to which the probe light is input, to the second optical directional coupler via a variable optical attenuator and an optical phase shifter; and a bandpass filter connected to the second optical directional coupler.

Abstract: An optical gate switch circuit includes: an asymmetric Mach-Zehnder interferometer having an optical path that outputs control light and probe light to a second optical directional coupler via a first optical directional coupler and an optical phase modulation element, and another optical path that connects a third optical directional coupler to which the probe light is input, to the second optical directional coupler via a variable optical attenuator and an optical phase shifter; and a bandpass filter connected to the second optical directional coupler.

Abstract: An optical phase modulation circuit includes an optical phase modulation element, an optical bandpass filter, and an optical directional coupler, wherein control light with a wavelength of ?C is coupled with probe light with a wavelength of ?P using the optical directional coupler and input to the optical phase modulation element, the probe light that has been phase modulated by the optical phase modulation element is extracted through the optical band pass filter, and the phase of the probe light is modulated in response to the intensity of the control light.

Abstract: An optical phase modulation circuit includes an optical phase modulation element, an optical bandpass filter, and an optical directional coupler, wherein control light with a wavelength of ?C is coupled with probe light with a wavelength of ?P using the optical directional coupler and input to the optical phase modulation element, the probe light that has been phase modulated by the optical phase modulation element is extracted through the optical bandpass filter, and the phase of the probe light is modulated in response to the intensity of the control light.

Abstract: A method of generating a single-sideband optical frequency comb uses an optical fiber loop that contains an optical modulator and an optical amplifier. The optical modulator is used to generate a sideband signal on only one side of a reference signal. The signal thus generated is circulated in the fiber loop while using the amplifier to compensate for optical loss in the course of the circulation.

Abstract: A method of generating a single-sideband optical frequency comb uses an optical fiber loop that contains an optical modulator and an optical amplifier. The optical modulator is used to generate a sideband signal on only one side of a reference signal. The signal thus generated is circulated in the fiber loop while using the amplifier to compensate for optical loss in the course of the circulation.