A frequency modulated continuous wave LiDAR system is disclosed that may be scalable and integrated in compact and demanding environments. The improved system of the present disclosure includes: an electro-optic modulator configured to modulate a laser generated by a laser source; a balanced photo detector configured to process an interference signal of a local copy of the laser coupled with a signal of the laser returned from a target and output a beatnote signal; a modulation source with two outputs, wherein the modulation source is configured to sweep in phase across a required bandwidth for the electro-optic modulator and the balanced photo detector; and a Frequency Information Rapid Extraction for Ranging Applications (“FIRE-RA”) system configured to: receive the interference signal from the balanced photo detector, process the interference signal with a signal from one of the two outputs of the modulation source for the balanced photo detector, and output distance and speed data for the target according to the processed interference signal.

Various technologies described herein pertain to a SPAD lidar system that includes a transmitter and a receiver. The transmitter is configured to transmit a transmitted electromagnetic signal into an environment nearby the SPAD lidar system, and the receiver is configured to receive a received electromagnetic signal from the environment nearby the SPAD lidar system. The receiver includes a SPAD sensor array (which includes SPAD pixels) and a binning system. The received electromagnetic signal is inputted to the SPAD pixels of the SPAD sensor array. The binning system is configured to combine outputs of groups of the SPAD pixels to generate combined outputs for the groups and assign the combined outputs to SPAD pixels in the groups, where the groups are overlapping. A processing system of the SPAD lidar system can generate lidar data based on the combined outputs.

An optical sensor system includes a set of epitaxial layers formed on a semiconductor substrate. The set of epitaxial layers defines a semiconductor laser having a first multiple quantum well (MQW) structure. Electromagnetic radiation is generated by the first MQW structure, emitted from the first MQW structure, and self-mixed with a portion of the emitted electromagnetic radiation that is returned to the first MQW structure. The set of epitaxial layers also defines a second MQW structure operable to generate a first photocurrent responsive to detecting a first emission of the semiconductor laser, and a third MQW structure operable to generate a second photocurrent responsive to detecting a second emission of the semiconductor laser. The optical sensor system also includes a circuit configured to generate a self-mixing interferometry (SMI) signal by combining the first photocurrent and the second photocurrent.

A wearable device includes a device housing configured to be worn on a first surface of a user, a set of one or more SMI sensors, and a processor. The set of one or more SMI sensors is mounted within the device housing and configured to emit a set of one or more beams of electromagnetic radiation, with each beam emitted in a different direction extending away from the first surface. The set of one or more SMI sensors is also configured to generate a set of one or more SMI signals containing information about a relationship between the device housing and a second surface. The processor is configured to extract the relationship between the device housing and the second surface from digitized samples of the set of one or more SMI signals.

A portable electronic device is operable in a particulate matter concentration mode where the portable electronic device uses a self-mixing interferometry sensor to emit a beam of coherent light from an optical resonant cavity, receive a reflection or backscatter of the beam into the optical resonant cavity, produce a self-mixing signal resulting from a reflection or backscatter of the beam of coherent light, and determine a particle velocity and/or particulate matter concentration using the self-mixing signal. The portable electronic device is also operable in an absolute distance mode where the portable electronic device determines whether or not an absolute distance determined using the self-mixing signal is outside or within a particulate sensing volume associated with the beam of coherent light. If not, the portable electronic device may determine a contamination and/or obstruction is present that may result in inaccurate particle velocity and/or particulate matter concentration determination.

A light detection and ranging (LIDAR) system includes a transmitter, a receiving pixel, a rotating mirror, and a beam displacement apparatus. The transmitter is configured to emit a transmit beam. The receiving pixel is configured to receive a returning beam. The rotating mirror is configured to direct the transmit beam to a target and direct the returning beam to the receiving pixel. The beam displacement apparatus is disposed between the receiving pixel and the rotating mirror. The beam displacement apparatus is configured to introduce a displacement to the returning beam to compensate for a spacing between the transmitter and the receiving pixel.

A sensor system includes a self-mixing interferometry sensor; a drive circuit configured to apply a modulated drive signal to an input of the self-mixing interferometry sensor; a mixer circuit configured to mix a modulated output of the self-mixing interferometry sensor with a local oscillator signal that is orthogonal to the modulated drive signal over a period of time; an integrator circuit configured to integrate an output of the mixer circuit over the period of time; and a processor configured to determine, using an output of the integrator circuit, at least one of a round-trip propagation time of electromagnetic radiation emitted by the self-mixing interferometry sensor and reflected back into the self-mixing interferometry sensor by an object or medium, or a velocity of the object or medium.

The invention describes a laser sensor or laser sensor module (100) using self-mixing interference for particle density detection, a related method of particle density detection and a corresponding computer program product. The invention further relates to devices comprising such a laser sensor or laser sensor module. It is a basic idea of the present invention to detect particles by means of self-mixing interference signals and determine a corresponding particle density. In addition at least a first parameter related to at least one velocity component of a velocity vector of the particles is determined in order to correct the particle density if there is the relative movement between a detection volume and the particles. Such a relative movement may for example be related to a velocity of a fluid transporting the particles (e.g. wind speed). Furthermore, it is possible to determine at least one velocity component of the velocity of the particles based on the self-mixing interference signals.

A method and system to implement the method of measuring a change in an optical path length using differential laser self-mixing interferometry. The method includes obtaining a reference SMI signal (Sr) and a main measurement SMI signal (Sm) of a laser (LD) and determining the relative change in the optical path length between the (LD) and a target (T) in a range between 0 and λ/2, by comparing the relative positions along time of fringes or transitions of the (Sm) and (Sr). The (Sr) and the (Sm) are obtained at different moments once backscattered laser light (br) is generated from the reflection on said target (T) of a reference and a main measurement laser light beam emitted by the laser (LD) and while being modulated according to a specific modulation pattern that maintained while both the (Sr) and the (Sm) are acquired and has re-entered its laser cavity.

This device for determining wind speed comprises at least two laser sources emitting beams in different directions that are coplanar and such that each emission direction corresponds to a perpendicular emission direction. Each laser source is associated with focusing optics for focusing the emitted beam, a laser diode for receiving a reflected beam obtained after reflection by a particle present in the air of the corresponding emitted beam, a photodiode for transmitting an interference signal occurring between the emitted beam and the reflected beam, a processor for processing the obtained interference signals, and an optical cavity into which the reflected beam is reinjected in order to obtain an interference with the emitted beam.