An electro-optical distance meter comprises a light source for emitting a distance measuring light, a distance measuring optical system for leading a distance measuring light to a photodetector, an internal reference optical system for leading a part of the distance measuring light as an internal reference light to the photodetector, and an arithmetic processing unit for performing a distance measurement based on light receiving results of the distance measuring light and the internal reference light, wherein the internal reference optical system comprises a condenser lens, a scattering plate for scattering the internal reference light and for forming a secondary light source, and an optical fiber for leading the internal reference light to the photodetector and the internal reference optical system is constituted in such a manner that a light component of the internal reference light emitted from an arbitrary point within a whole surface of the secondary light source enters the optical fiber.

A laser radar device includes: a modulator (8) 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 (14) in which a frequency band including frequencies of signal components included in a plurality of beat signals detected by an optical heterodyne receiver (13) 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 (15) for sampling the beat signals passing through the band pass filter (14) at a sampling frequency.

An optical device for the contactless measurement of a liquid level contained in a storage device by an optical signal, the optical device including an optical unit fixedly positioned above the storage device and an electronic control unit capable of emitting an optical signal, dissociated from the optical unit and positioned at a distance from the optical unit. The optical unit includes a single channel for the emission and the reception of the optical signal. The optical unit is connected to the electronic control unit through an optical fibre capable of transmitting the optical signal emitted by the electronic control unit and an optical signal reflected by the liquid. The optical fibre has first and second optical cores that juxtapose each other such that at least a part of the optical signal emitted in the first optical core of the optical fibre is backscattered in the second optical core.

A test apparatus has at least one optical source, a high-speed photodetector, a microcontroller or processor, and electrical circuitry to power and drive the optical source, high-speed photodetector, and microcontroller or processor. The apparatus measures the frequency response and optical path length of a multimode optical fiber under test, utilizes a reference VCSEL spatial spectral launch condition and modal-chromatic dispersion interaction data to estimate the channels total modal-chromatic bandwidth of the fiber under test, and computes and presents the estimated maximum data rate the fiber under test can support.

Embodiments of this application provide a radar system, and a signal processing method and apparatus. The radar system includes: a transmitting assembly, a receiving assembly, and a controller. The transmitting assembly is configured to generate and transmit N first signals, where characteristics of the N first signals are different, the characteristic includes a wavelength and/or a delay, and N is an integer greater than 1; the receiving assembly is configured to receive a second signal; and the controller is configured to determine, based on the characteristics of the N first signals, whether the second signal includes an echo signal corresponding to the first signal.

A phase shifter includes a substrate layer, a cladding layer, and a waveguide. The phase shifter includes a waveguide and a heating element. The phase shifter includes a thermally conductive structure disposed on the cladding layer to disperse heat from the waveguide. The thermally conductive structure may include a metal strip disposed longitudinally along the beam, may include thermally conductive pads, and/or may include thermally conductive vias coupled between the cladding layer and the substrate layer. The phase shifter may be incorporated into light detection and ranging (LIDAR) devices, telecommunications devices, and/or computing devices.

Embodiments discussed herein refer to LiDAR systems and methods that monitor for fault conditions that could potentially result in unsafe operation of a laser. The systems and methods can monitor for faulty conditions involving a transmitter system and movement of mirrors in a scanning system. When a fault condition is monitored, a shutdown command is sent to the transmitter system to cease laser transmission. The timing by which the laser should cease transmission is critical in preventing unsafe laser exposure, and embodiments discussed herein enable fault detection and laser shutoff to comply with laser safety standards.

A method for calibrating a LIDAR system proposes incorporating in the LIDAR system a reference optical path which is formed from an optical fiber. The length of the optical fiber determines a measurement reference value, which can then be used to evaluate distances of targets to be characterized using the LIDAR system. The calibration method is simple and economical to implement. It may be used in particular for a LIDAR system which is designed to perform air speed measurements, in particular on board an aircraft.

A light detection and ranging (LIDAR) apparatus is provided that includes a laser source configured to emit a laser beam in a first direction. The apparatus also includes lensing optics configured to pass a first portion of the laser beam in the first direction toward a target, return a second portion of the laser beam into a return path as a local oscillator signal, and return a target signal into the return path. The apparatus also includes a quarter-wave plate configured to polarize the laser beam headed in the first direction and polarize the target signal returned through the lensing optics. The apparatus also includes a polarization beam splitter configured to pass non-polarized light through the beam splitter in the first direction and reflect polarized light in a second direction different than the first direction, wherein the polarization beam splitter is further configured to enable interference between the local oscillator signal and the target signal to generate a mixed signal. The apparatus also includes an optical detector configured to receive the mixed signal.

A system includes a light source, an optical splitter, and a pulse-energy measurement circuit. The light source is configured to generate an emitted beam of light that includes an emitted pulse of light. The optical splitter is configured to split the emitted beam of light to produce at least (i) a test beam of light that includes a test pulse of light, the test pulse of light including a first portion of the emitted pulse of light and (ii) an output beam of light that includes an output pulse of light, the output pulse of light including a second portion of the emitted pulse of light allowed to at least in part exit the system. The pulse-energy measurement circuit is configured to receive the test pulse of light and determine a numerical value corresponding to an individual energy amount of the test pulse of light.