Abstract: A semiconductor laser source of a transmitter (102) in a range imaging apparatus (100) generates an optical pulse at repeated moments, and outputs spatially separate optical beams towards a target zone (114), such that the semiconductor laser source outputs each of the spatially separate of the optical beams at different moments from each other. A detector (105) of a receiver (104) comprises single-photon sub-detector units, at least two groups of the single-photon sub-detector units have separate field of views towards the target zone (114), and the at least two groups of sub-detector units are associated with different optical beams of the spatially separated optical beams on the basis of the separate field-of-views. A timing unit (106) determines a value corresponding to a time-of-flight of the optical pulse output at each of the repeated moments on the basis of a signal from a group of the sub-detector units associated with an optical beams output at said moment.

Abstract: An apparatus is configured to operate in a single fundamental transverse mode and the apparatus includes a waveguide layer between an n-doped cladding layer and a p-doped cladding layer. The waveguide layer includes a first waveguide part, and an active layer located between the first waveguide part and the p-doped cladding layer, the active layer being asymmetrically within the waveguide layer closer to the p-doped cladding layer than the n-doped cladding layer. The refractive index of the n-doped cladding layer being equal to or larger than the p-doped cladding layer. A first end of the first waveguide part is adjacent to the n-doped cladding layer. A second end of the first waveguide part is adjacent to a first end of the active layer. A desired donor density is doped in the first waveguide part for controlling the carrier density dependent internal optical loss in the first waveguide part at high injection levels.

Abstract: An optical time-of-flight distance measuring device comprises a transmitter and a receiver. The transmitter comprises a semiconductor laser for outputting optical pulses of controllably variable temporal widths. The semiconductor laser operates in an enhanced switching regime for the optical pulses of a minimum generable temporal width of the laser. The receiver comprises a matrix of single photon avalanche detector elements of a Geiger mode, a receiver controller, and one or more time-to-digital converters. The single photon avalanche detector elements detect optical pulses reflected from the target to the matrix, and each of the single photon avalanche detector element outputs an electric signal in response to each detection. A number of the time-to-digital converters is smaller than a number of the single photon avalanche detector elements of the matrix. The receiver controller connects at least two of the single photon avalanche detector elements with different time-to-digital converters.

Abstract: A range imaging apparatus comprises a semiconductor laser transmitter, a receiver, and a data processing unit, a field-of-illumination of the semiconductor transmitter and a field-of-view of the receiver being overlapping. The receiver comprises single photon avalanche detector elements arranged two-dimensionally and operate in a Geiger mode. The semiconductor laser transmitter generates optical pulses repeatedly, a single optical pulse of the optical pulses being output as an optical beam with one or more stripes, which are parallel, one above another, and separate from each other. Each of the stripes of optical beams, which are reflected from objects within the field-of-view, illuminates a detector element configuration of the single photon avalanche detector elements.

Abstract: A semiconductor laser source of a transmitter (102) in a range imaging apparatus (100) generates an optical pulse at repeated moments, and outputs spatially separate optical beams towards a target zone (114), such that the semiconductor laser source outputs each of the spatially separate of the optical beams at different moments from each other. A detector (105) of a receiver (104) comprises single-photon sub-detector units, at least two groups of the single-photon sub-detector units have separate field of views towards the target zone (114), and the at least two groups of sub-detector units are associated with different optical beams of the spatially separated optical beams on the basis of the separate field-of-views. A timing unit (106) determines a value corresponding to a time-of-flight of the optical pulse output at each of the repeated moments on the basis of a signal from a group of the sub-detector units associated with an optical beams output at said moment.

Abstract: An apparatus is configured to operate in a single fundamental transverse mode and the apparatus includes a waveguide layer between an n-doped cladding layer and a p-doped cladding layer. The waveguide layer includes a first waveguide part, and an active layer located between the first waveguide part and the p-doped cladding layer, the active layer being asymmetrically within the waveguide layer closer to the p-doped cladding layer than the n-doped cladding layer. The refractive index of the n-doped cladding layer being equal to or larger than the p-doped cladding layer. A first end of the first waveguide part is adjacent to the n-doped cladding layer. A second end of the first waveguide part is adjacent to a first end of the active layer. A desired donor density is doped in the first waveguide part for controlling the carrier density dependent internal optical loss in the first waveguide part at high injection levels.

Abstract: An apparatus, includes an illuminating light source and illuminating optics arranged to illuminate a sample region with illuminating light pulses, light gathering optics to gather Raman scattered light pulses from the sample region, a spectral disperser and a detector array for measuring the spectral intensity distribution of Raman scattered light pulses obtained from the sample region and an auxiliary detector for providing an indicator signal indicative of elastic scattering coefficient of the sample region. The apparatus is arranged to form a first output spectrum from the spectral intensity distribution of a first group of Raman scattered light pulses. The pulses of the first group of Raman scattered light pulses are obtained from the sample region when the indicator signal indicates that an object is located in the sample region.

Abstract: An optical time-of-flight distance measuring device comprises a transmitter and a receiver. The transmitter comprises a semiconductor laser for outputting optical pulses of controllably variable temporal widths. The semiconductor laser operates in an enhanced switching regime for the optical pulses of a minimum generable temporal width of the laser. The receiver comprises a matrix of single photon avalanche detector elements of a Geiger mode, a receiver controller, and one or more time-to-digital converters. The single photon avalanche detector elements detect optical pulses reflected from the target to the matrix, and each of the single photon avalanche detector element outputs an electric signal in response to each detection. A number of the time-to-digital converters is smaller than a number of the single photon avalanche detector elements of the matrix. The receiver controller connects at least two of the single photon avalanche detector elements with different time-to-digital converters.

Abstract: A receiver unit includes at least one single photon avalanche detector element of a Geiger mode and a time-to-digital converter circuit. Each single photon avalanche detector element is enabled to detect a photon in at least one time-gated window, and each single photon avalanche detector element is configured to output an electric pulse in response to detection of a photon of optical radiation within the at least one time-gated window. The time-to-digital converter circuit provides timing data associated with said electric pulse for determination of a distance of a target on the basis of the timing data provided by the time-to-digital converter circuit.

Abstract: An apparatus, includes an illuminating light source and illuminating optics arranged to illuminate a sample region with illuminating light pulses, light gathering optics to gather Raman scattered light pulses from the sample region, a spectral disperser and a detector array for measuring the spectral intensity distribution of Raman scattered light pulses obtained from the sample region and an auxiliary detector for providing an indicator signal indicative of elastic scattering coefficient of the sample region. The apparatus is arranged to form a first output spectrum from the spectral intensity distribution of a first group of Raman scattered light pulses. The pulses of the first group of Raman scattered light pulses are obtained from the sample region when the indicator signal indicates that an object is located in the sample region.

Abstract: A single pulse semiconductor laser operating in the gain-switching regime comprises a plane asymmetric waveguide and an active layer in the waveguide, the ratio of a thickness of the active layer to an optical confinement factor of the laser being extremely large, larger than about 5 ?m, for example.

Abstract: An apparatus comprises a semiconductor single-photon avalanche detector, and a counter. The detector performs detections of photons of optical radiation caused by an optical excitation pulse to the object. The counter measures timing of each detection made in the detector with respect to the excitation pulse causing the detected photons, and performs at least one of the following: forming a number of Raman detections, forming a number of fluorescence detections. Forming the number of the Raman detections is performed by eliminating an estimate of a number of fluorescence photons in the measurement. Forming the number of the fluorescence detections is performed by eliminating an estimate of a number of Raman photons in the measurement. The estimates are formed in a predetermined manner from the number and timing of the detections.

Abstract: The invention concerns an optical remote sensing system, comprising a reaction chamber adapted to host a chemical reaction in the shape of a scattering turbid atmosphere inside the reaction chamber. An optical active sensor is used to detect the three dimensional structure of an accumulation, such as a heap, inside the reaction chamber, suggesting various measurement methods.

Abstract: An apparatus comprises a semiconductor single-photon avalanche detector, and a counter. The detector performs detections of photons of optical radiation caused by an optical excitation pulse to the object. The counter measures timing of each detection made in the detector with respect to the excitation pulse causing the detected photons, and performs at least one of the following: forming a number of Raman detections, forming a number of fluorescence detections. Forming the number of the Raman detections is performed by eliminating an estimate of a number of fluorescence photons in the measurement. Forming the number of the fluorescence detections is performed by eliminating an estimate of a number of Raman photons in the measurement. The estimates are formed in a predetermined manner from the number and timing of the detections.

Abstract: A receiver unit includes at least one single photon avalanche detector element of a Geiger mode and a time-to-digital converter circuit. Each single photon avalanche detector element is enabled to detect a photon in at least one time-gated window, and each single photon avalanche detector element is configured to output an electric pulse in response to detection of a photon of optical radiation within the at least one time-gated window. The time-to-digital converter circuit provides timing data associated with said electric pulse for determination of a distance of a target on the basis of the timing data provided by the time-to-digital converter circuit.

Abstract: A vertical cavity surface emitting laser (VCSEL) configured to operate in a gain switching regime includes a cavity that is terminated by reflectors at both ends for enabling a standing wave of optical radiation therebetween. The cavity comprises at least one quantum well, each of the quantum wells located at a position where a value of a standing wave factor for each quantum well is between zero and one, 0<?<1.

Abstract: An apparatus comprises a plurality of detecting elements and a summer. Each detecting element receives and detects different bands of spectrum of Raman radiation formed in response to at least one optical excitation pulse directed to the object. The detecting elements and/or the summer receives a command to enable registration of detections in the detecting elements and a command to disable the registration during or after the Raman radiation. The summer registers separately the detections of the Raman radiation in at least two detecting elements for presenting data on the object on the basis of the detections.

Abstract: A vertical cavity surface emitting laser (VCSEL) configured to operate in a gain switching regime includes a cavity that is terminated by reflectors at both ends for enabling a standing wave of optical radiation therebetween. The cavity comprises at least one quantum well, each of the quantum wells located at a position where a value of a standing wave factor for each quantum well is between zero and one, 0<?<1.

Abstract: There is provided an apparatus (300) for measuring a distance to a target (312), comprising: a transmitter (302) configured to transmit an optical pulse (310) towards the target (312), a receiver channel (304) configured to receive the optical pulse (310) reflected from the target (312), and a processor (306) configured to measure a time intervaf between the transmission and detection of the optical pulse (310) at a predefined amplitude threshold level (11OA, 110B), to determine a time domain parameter from the detected optical pulse (310) at one or more amplitude threshold levels (110A, 110B), to convert the time domain parameter value into a correction value by a conversion model; to correct a timing error in the measured time interval by the correction value, and to convert the error-corrected time interval into a distance to the target (312).

Abstract: An apparatus comprises a plurality of detecting elements and a summer. Each detecting element receives and detects different bands of spectrum of Raman radiation formed in response to at least one optical excitation pulse directed to the object. The detecting elements and/or the summer receives a command to enable registration of detections in the detecting elements and a command to disable the registration during or after the Raman radiation. The summer registers separately the detections of the Raman radiation in at least two detecting elements for presenting data on the object on the basis of the detections.