Oulun Yliopisto

Teknologian Tutkimuskeskus Vtt

Nokia Mobile Phones Limited

University of York

Timegate Instruments Oy

Noptel Ky

Rautaruukki Oy, a Corp. of Finland

Teknologian Tutkimuskeskus Vtt Oy

Juha Kostamovaara

Jussi Tenhunen

Boris Ryvkin

Eugene A Avrutin

Juha H Rapeli

Harri Kopola

Lauri Kurki

Risto Myllyla

Raimo Ahola

Pasi Palojärvi

Matti Karras

Jan Nissinen

Pekka Keränen

Timo Rahkonen

Rami Aikio

Jani Pehkonen

Sergey Vainshtein

Larisa Shestak

Ilkka Nissinen

Mikhail Sverdlov

A semiconductor laser source of a transmitter () in a range imaging apparatus () generates an optical pulse at repeated moments, and outputs spatially separate optical beams towards a target zone (), such that the semiconductor laser source outputs each of the spatially separate of the optical beams at different moments from each other. A detector () of a receiver () 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 (), 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 () 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. In an embodiment, the semiconductor laser source comprises a plurality of sub-source units each of which may output a unique optical beam. In an embodiment, the timing unit () comprises a selector and a number of time-to-digital converters (). The receiver selector connects a number of the sub-detector units, which detect the optical pulse () and the number of which corresponds to the number of output beams, with the number of the time-to-digital converters (). In an embodiment, the apparatus () comprises an electric power source () which supplies a constant electric power to the semiconductor laser source at each of the repeated moments in order to increase brightness of the optical beams. Elongated optical beams may be produced by a laser diode bar (several emitting stripes) and a cylinder lens system or a holographic diffuser. Partially overlapping optical beams may provide illuminated rectangles of the optical beams on the target ().

Range imaging apparatus and method

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.

Method of manufacturing optical semiconductor apparatus and the apparatus

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. The time-to-digital converters connected with the single photon avalanche detector elements provide timings of detected optical pulses on the basis of each output electrical signal for determination of information associated with a distance of the target.

Distance measuring device and transmitter, receiver and method thereof

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.

Method and apparatus for measuring inelastic scattering

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.

Distance measurement device, receiver thereof and method of distance measurement

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 &#x3bc;m, for example.

Semiconductor laser

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.

Measurement of raman radiation

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&#x3c;&#x3be;&#x3c;1.

Laser

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.

There is provided an apparatus () for measuring a distance to a target (), comprising: a transmitter () configured to transmit an optical pulse () towards the target (), a receiver channel () configured to receive the optical pulse () reflected from the target (), and a processor () configured to measure a time intervaf between the transmission and detection of the optical pulse () at a predefined amplitude threshold level (OA,B), to determine a time domain parameter from the detected optical pulse () at one or more amplitude threshold levels (A,B), 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 ().

Method and device for measuring distance

The invention relates to a method and an arrangement for performing triggering and for determining a triggering moment. In the solution, a unipolar electrical pulse of a detector () is converted between the detector () and a first amplifier () succeeding the detector into at least one bipolar electrical oscillation. The bipolar electrical oscillation is amplified with at least one amplifier () and triggering is performed at a zero level between the extreme values of the bipolar electrical oscillation. In addition, a triggering moment is determined, at which the amplified bipolar electrical oscillation crosses the zero level between its extreme values.

Method and arrangement for performing triggering and timing of triggering

An apparatus and a method are provided for generating an optical pulse by using a current pulse. The arrangement is based on a specific semiconductor structure, where a carrier injector is separated from the optically active region by a potential barrier for the injected carriers and on low carrier mobility in the semiconductor component, which features give rise to formation of a current-assisted strong electric field in the optically active region at moderate current densities before positive net gain is achieved. The current-assisted electric field broadens the gain spectrum in the active layer thus suppressing positive net gain and permitting carrier accumulation in the active layer. When the current pulse is stopped, the positive net gain is achieved, giving rise to an optical emission from the active layer.

Method of generating optical radiation, and optical radiation source

Range-finding method and device

An FM or PM signal is demodulated so that the cycle time of the modulated input signal is measured using a time-to-digital converter comprising a counter that uses a moderate clock frequency as a reference clock, a digital delay line interpolator and a control circuitry. The counter is used for rough digitization and the delay line for interpolating the moment of zero-crossing inside a clock cycle. Total delay of the delay line, i.e., the range of time intervals the interpolator is able to measure, is actively kept equal to the cycle time of the reference clock. When the number of delay elements in the delay line is a power of two, the result of the delay line interpolator may be used directly as the least significant bits of the measurement.

Method and circuitry for demodulation of angle modulated signals by

Designs of prior art art not usable in efficient dry-run target practice with hand firearms. The greatest drawbacks are, for instance, that it is not possible by the method to monitor the result of the dry-run training; that the method or means is not liable on ordinary guns without special measures or not at all or the method is so complicated that its implementation in practice causes that the means is too expensive to be in the personal possession and use of shooters. In order to eliminate said drawbacks, the invention is mainly characterized in that by a transmitter/receiver means attachable to conventional arms is emitted an optical beam towards a surface serving as the target which is set off from its surroundings due to its optic radiation reflecting properties relative to those of its surroundings, the hitting or missing of the beam being observed with the receiver on the basis of the return beam.

Growing community of inventors

Oulu, Finland

Juha Kostamovaara