942results about "Sagnac effect gyrometers" patented technology

A method of examining a sample, which includes: exposing a reference to a first set of electromagnetic radiation, to form a second set of electromagnetic radiation scattered from the reference; exposing a sample to a third set of electromagnetic radiation to form a fourth set of electromagnetic radiation scattered from the sample; and interfering the second set of electromagnetic radiation and the fourth set of electromagnetic radiation. The first set and the third set of electromagnetic radiation are generated from a source; at least a portion of the second set of electromagnetic radiation is of a frequency different from that of the first set of electromagnetic radiation; and at least a portion of the fourth set of electromagnetic radiation is of a frequency different from that of the third set of electromagnetic radiation.

An integrated optical circuit for use in a fibre optic gyroscope which senses rotation rates by determining a phase shift due to the Sagnac Effect between light beams travelling around an optical fibre sensing loop (4) in opposite directions, the circuit being provided on a silicon-on-insulator chip comprising a layer of silicon separated from a substrate by an insulating layer, the circuit comprising: rib waveguides (11) formed in the silicon layer for receiving light from a light source (2) and transmitting light to a light detector (3), fibre optic connectors (9) in the form of grooves etched in the silicon layer for receiving the respective ends of the optical fibre sensing loop (4); rib waveguides (11) formed in the silicon layer for transmitting light to and from said fibre optic connectors (9) so as to direct light beams in opposite directions around the sensing loop (4) and receive light beams returning therefrom, phase determining means and (13,17,31) integrated in silicon layer for determining a phase shift between the light beams returning from the sensing loop (4).

A temperature compensation method for denoising a fiber-optic gyroscope on the basis of time series analysis comprises four steps of: step 1, designing an experimental scheme, performing fixed point low and high temperature testing experiment on the fiber-optic gyroscope, and utilizing acquisition software for data acquisition; step 2, performing time series analysis on the zero offset data of the gyroscope, and establishing the mathematical model of the random error of the fiber-optic gyroscope; step 3, adopting a kalman filtering algorithm to filter random noise in the zero offset data of the fiber-optic gyroscope; and step 4, utilizing the data which is de-noised by the kalman filtering to identify the model structure of the temperature shift error of the fiber-optic gyroscope, and calculating the parameters of the identified model. The method establishes the multinomial model of the static temperature shift error of the fiber-optic gyroscope through time series analysis, kalman filtering denoising treatment and identification of the temperature shift error model structure and parameters. The method completely meets the real-time compensation requirement on the project, and has a better practicable value and a wide application prospect in the technical field of aerospace navigation.

Methods and apparatus are provided for determining the rotational rate of an optical gyro. An optical gyro comprises at least one substrate, a multi-frequency light source (MFLS) mounted on the substrate, and a resonator coupled to the MFLS. The MFLS is configured to produce a first light beam having a first frequency and a second light beam having a second frequency and phase locked with the first light beam. The resonator comprises an optical fiber coil having a hollow core. The resonator is configured to circulate a portion of each of the first and second light beams through the hollow core. The portion of the first light beam propagates in a first counter-propagating direction, and the portion of the second light beam propagates in a second counter-propagating direction. A measured difference between the first and second frequencies indicates a frequency shift proportional to the rotation rate of the optical gyro.

The invention relates to an integral structure of a triaxial optical fiber gyro inertia measuring unit, which comprises a mounting skeleton, three fiber optic gyro scopes, three accelerometers, a light source, a circuit board and a vibration damper. The mounting skeleton adopts a hollow hexahedron frame structure, each group of mounting holes are symmetrically arranged, and mounting lug bosses are arranged on the positioning end surface of the mounting holes. Three fiber optic gyro scopes form mutual space and are orthogonally arranged on the outer surface of the mounting skeleton, the light source and the circuit board are respectively arranged on the outer surface of the mounting skeleton which is corresponding to the three fiber optic gyro scopes, the three accelerometers form the mutual space and are orthogonally arranged on the inner surface of the mounting skeleton which is corresponding to the three fiber optic gyro scopes and near the geometric center of the mounting skeleton, and the vibration damper is arranged on the outer surface of the mounting skeleton. The measuring unit has the advantages that the quality is light; the degree of deviation between the mass center of an inertia measuring unit and the geometric mounting center is very small; the dynamic testing precision is high; the temperature field distribution of the inertia measuring unit is beneficial for the temperature compensation and control of each component, and the like.

An apparatus for analyzing, identifying or imaging an target including an integrated dual laser module coupled to a pair of photoconductive switches to produce cw signals in the range of frequencies from 100 GHz to over 2 THz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral homodyne process to generate an electrical signal representative of some characteristics of the target with resolution less than 250 MHz. The photoconductive switches are activated by laser beams from the dual laser module. The lasers in the module are tuned to different frequencies and a phase shifter in the path of one beam allows the beams to have an adjustable phase difference.

A system and method is provided which suppresses relative intensity noise in a fiber optic gyroscope by taking advantage of the frequency response of erbium fiber. In operation, the gain provided by the erbium fiber is added to the gain of the other components in the feedback loop to provide for stable loop performance up to about 250 kHz. The frequency response of the erbium fiber of about 3 kHz also provides a 6 db per octave roll-off, which, when used in a negative feedback control loop for controlling the current flowing to the gyroscope light source, allows for a relative intensity noise control loop with a bandwidth much greater than 3 kHz; this may be used in high performance gyroscope applications.

A method is provided for sensing an environmental effect upon a sensing element and includes exposing the sensing element into the environmental effect, producing a light signal in the sensing element, modulating the light signal with a modulation signal, and determining a path length of the light signal as a function of the modulation signal. A fiber optic sensor is provided that includes a light source producing a light, a sensing element optically coupled to the light source such that the light propagates through the sensing element, a detector optically coupled to the sensing element. The detector detects light intensity propagating in the sensing element. An electronics processor receives the detector output and produces a modulation signal for the light. The processor further produces an output signal indicative of the environmental effect as a function of the modulation signal.

The INERTIAL SENSOR TRACKING SYSTEM is an overall system installation consisting of wireless body pack transmitters, broadband telemetry transceivers, computer and monitoring equipment, and emergency power generation for tracking personnel in an underground mine environment. The system is designed to function with normal primary power and on battery operation in the event of an emergency. In the past inertial sensors have been large spinning mass gyroscopes and large mass-based accelerometers. These inertial sensors have required high voltage three phase electrical supplies. The “wearable” body pack must be battery operated and the sensors must be small and lightweight. Micro-Electro-Mechanical (MEM) sensors fulfill both the requirements of low weight and low power consumption. The accuracy of the MEM sensor has been developed sufficiently to incorporate, with de-noising algorithms, an accurate position-sensing device. The proliferation of broadband TCP/IP protocol based RF systems provides a standardized medium of transmission, which will work in an underground environment.

The invention discloses a dual-polarization interferometric fiber-optic gyro which belongs to the field of communication technology. The fiber-optic gyro comprises a light source, two linear polarized light generating circuits, two signal detection light paths, a polarized beam splitter/combiner, a polarization-maintaining coupler, a phase modulator and a polarization-maintaining fiber-optic ring; wherein the light source is connected with the input ends of the two linear polarized light generating circuits by optic fibers; two output ends of the two linear polarized light generating circuits are respectively connected with two ports at the same side of the polarized beam splitter/combiner by optic fibers through one signal detection light path; the port at the other side of the polarized beam splitter/combiner is connected with the polarization-maintaining fiber-optic ring through the polarization-maintaining coupler; and the phase modulator is connected between the polarization-maintaining fiber-optic ring and the polarization-maintaining coupler by optic fibers. Compared with the prior art, the fiber-optic utilizes the dual-polarized light to carry out the detection, thereby greatly improving the measuring precision and the measuring stability of the rotating angular velocity; meanwhile, the fiber-optic gyro has the advantages of simple structure, low cost, small volume, high sensitivity and wide application range simultaneously.

The invention discloses a fiber optic gyroscope temperature drift modeling method by optimizing a dynamic recurrent neural network through a genetic algorithm. The fiber optic gyroscope temperature drift modeling method by optimizing the dynamic recurrent neural network through the genetic algorithm comprises the following steps of (1) initializing network parameters, and establishing an improved Elman neural network model; (2) obtaining a training and testing sample; (3) training an improved Elman neural network, and optimizing model parameters through the genetic algorithm; (4) outputting forecasts of an fiber optic gyroscope, and compensating errors. The output of the fiber optic gyroscope processed through a denoising algorithm is trained by introducing the improved Elman neural model with self-feedback connection weight, constant iterative optimization is carried out on the model parameters through the genetic algorithm, and the optimal model is obtained according to the magnitude of the errors of the model under different parameters. According to the fiber optic gyroscope temperature drift modeling method by optimizing the dynamic recurrent neural network through the genetic algorithm, the complexity of the algorithm is taken into consideration, the accuracy of the fiber optic gyroscope temperature drift model is improved, the application of the fiber optic gyroscope temperature drift model in engineering is expanded, and certain practical significance is achieved.

An optical resonant modulator includes an optical ring resonator and an optical loop that is coupled to the optical ring resonator by two couplers. The optical ring resonator can have a hybrid design in which the ring resonator is formed on an electro-optically passive material and the optical loop is formed on an electro-optically active material. An amplification section can be inserted between the electro-optically passive and the electro-optically active sections. In analog applications, an optical resonator includes a Mach Zehnder interferometer section having an input and an output, with a feedback path coupling the output to the input. Applications of the optical modulator of the invention, and a method for modulating an optical signal also are disclosed.

The utility model discloses a method for testing the frequency properties of the photoelectric detector used for fiber optic gyroscopes. A signal generator produces sinusoidal signals and adds the signal to a light intensity modulator to carry out sinusoidal modulation on the optical power of the optical signal from the fiber source in order to produce an optical signal with sinusoidal components. The measured photodetector converts the modulated optical signal into an electrical signal and samples the electric signal by means of high-speed data acquisition card, then conducts narrowband filter and signal processing over the collected samples and calculates the corresponding frequency response. The frequency sequence pre-selected by a numerical control system changes the frequency at which the sine wave generator (NC) system sends out signals , tests a series of frequency point responses, which can be combined into an amplitude frequency response curve of the measured photodetector, and the curve is transmitted to the terminal computer for displaying and storage. By controlling all the test processes by numerical control system, the utility model has the advantages of automatic measurement, fast testing speed, high testing precision, and therefore is suitable for carefully weighing the photodetector frequency performance in the whole operating frequency range.

This invention discloses to a type of fiber gas lasers and fiber ring laser gyroscopes based on these fiber gas lasers. The fiber gas lasers comprise of excitation gases, optical resonator and excitation source, etc. The optical resonator is made by connecting two selected arms of a single mode fiber coupler to the two ends of hollow-core fiber to form a ring resonator. The hollow-core of the fiber is filled with excitation gases to act as gain medium. The fiber laser is simple to construct, lower cost, and has adjustable size and good amplification performance. The fiber ring laser gyroscopes based on this novel type of gas lasers can be applied on robotics, automobile navigation, etc.

Methods and systems for a compressive optical display and imager using optical scanning and selection and three-dimensional beamforming optics. Standard pixel data can generate a compressed image data set having custom pixel sizes, locations, and intensities. A 3-D beamformer optic adjusts its focus to produce the largest focused beam spot on the display screen corresponding to an image zone compressed pixel. Using scan mirror angular controls, display image space is painted using minimal numbers of laser beam spots whose sizes depend on the compressed sensed image. The imager includes movable reflecting optics to reflect an optical image and controllable imaging optics to pass the reflected optical image toward a digital micromirror that reflects +/−θ optical beams into +/−θ optical beam paths. A controller controls reflecting optics and agile front end imaging optics to receive an electronic image signal corresponding to detected +/−θ optical beams.

Embodiments of the invention allow the operation of confocal microscopes with relatively open pinholes (e.g. 1 Airy unit) whilst still giving a significant XY resolution improvement. In addition axial (Z) discrimination or resolution may also be improved. This is achieved by splitting the emitted light path in an interferometric fashion. One of the split beams is then directed inversion which inverts at least one coordinate in image space. The transformed beam and the non-transformed beam are then recombined in an interferometric fashion (i.e. coherently added), which provides an interference effect resulting in increased resolution of the image. Where the embodiments are being used in a confocal application, the resulting combined beam can then be subject to a spatially discriminating means, such as a pinhole, or the like.

The invention discloses a full digital temperature controller applied to optical fiber gyroscope inertia measurement combination, comprising seven temperature sensors, one DSP processor, two photoelectric coupler, seven-channel switch power amplifier and power supply circuit, where the DSP processor compares eN=TN-tn to control PWM wave generation, where tn is working temperature collected real-timely by temperature sensor and TN is set temperature, so as to drive heating component to make automatic adjustment control of heating current, which forms a closed-loop feedback device. And the invention controls working temperatures of the heating component and the controlled object, making them work at constant temperature, thus overcoming the effect of environmental temperature change on output accuracy of inertia components.

A method and system for monitoring the operating conditions of an electric generator. The system includes a triad sensor array formed within a predetermined section of a fiber optic conductor. The triad sensor array is formed of a group of sensors including a first sensor including a Bragg grating for producing a first signal representative of strain in a stator bar of the generator, a second sensor including a Bragg grating for producing a second signal representative of temperature in the stator bar, and a third sensor including a Bragg grating for producing a third signal representative of vibration amplitude in the stator bar.

An optical fibre gyroscope distributed layered temperature error compensation method comprises the following steps: (1) five optical components of a fiber-optic ring, a light source, a Y wave guide, a detector and a coupler are taken as temperature monitoring objects for determining the number of the temperature monitoring points of each optical component and the distributing form; (2) self-adapting recurrence and least squares treatment are carried out on monitoring value of each temperature monitoring point for obtaining temperature output value of the optical fibre gyroscope; (3) a neural network model is built for obtaining temperature drift compensation value by utilizing the temperature output value and the real time outputting data of the optical fibre gyroscope; (4) the real time outputting data of the optical fibre gyroscope minus the temperature drift compensation value means temperature compensation of the optical fibre gyroscope. The method can overcome the disadvantages of the prior art and reflect the temperature field inside the optical fibre gyroscope systematically and in an all-round way, and has significance in the performance research and improvement under the condition of the temperature environment of the optical fibre gyroscope.

Methods and apparatus are provided for attenuating rotation rate errors in a resonator gyro. The gyro includes a ring resonator having a hollow core optical fiber coil and optical elements that are selected and/or oriented to reduce stray light that may be present in input light beams introduced to the ring resonator. The resonator has a predetermined mode. One of the optical elements partially transmits a portion of the input light beam to a first end of the fiber coil while partially transmitting a portion of the input light beam to a filter. Light having the predetermined mode is accepted into the first end of the fiber coil, and the filter accepts light of the input light beam having a corresponding mode. Transmission components of the circulating light beams indicates resonance peaks of the counter-propagating directions of the ring resonator.

The invention provides an interference optical fiber gyroscope. The interference optical fiber gyroscope comprises a light source, a coupler, two signal detection optical paths, a linearly polarized light generation optical path and a polarization maintaining optical fiber ring, wherein the light source is connected with the coupler through an optical fiber; the two output ends of the coupler are connected with one signal detection optical path in the two signal detection optical paths through an optical fiber respectively; and the two signal detection optical paths are connected with the polarization maintaining optical fiber ring by optical fibers through the linearly polarized light generation optical path.

The invention relates to an apparatus for measuring inertia of a fiber gyro composite unit and its calibration method, and especially relates to the apparatus for measuring the inertia of the fiber gyro composite unit with miniaturization, high reliability and redundant multi-tables used for navigation, guidance and control of spacecrafts, which belongs to the inertia measurement technical field. The apparatus comprises a hexangular pyramid and a pedestal; six fiber gyroscopes are uniformly distributed on six side surfaces of the hexangular pyramid, six signal processing and interface circuits and six secondary power sources are arranged in the pedestal. According to the invention, the gravity center is positioned at a geometric center as possible, and the anti-mechanical capacity is good; the six fiber gyroscopes are redundant backup with each other; the reliability is high; in the process of in-orbit operation, a triaxial attitude angle speed can be still provided even the fault is generated by no more than three shafts at will, and the fault detection and the isolation can be realized. The calibration method can accurately calibrate zero position, scale factor and installation error, and can effectively enhance the in-orbit usage precision.

The invention is the project realizing method of fiber top inertia measuring device fast starting and precision guarantee, which adopts the temperature demarcating system to detect the temperature mode; found the module of the affirming parts of the fiber top and the quartz accelerator and effectively reduce the zero-bias brought by the temperature; implement small-wave transforming procession to the fiber top noises and make the stability of the zero-bias be better than 0.5 Deg./h and the zero-bias error be smaller than 10 to power 4 g. The invention effectively reduces the zero temperature floating and noises and improves the performance of the system.

A microchip ring trap for cold atoms or neutral molecules consists of a particular multi-layer layout of wires on a microchip. These conductive wires may be produced by photolithography on a substrate (e.g. gold on sapphire). There are four wires crucial to the design, essentially a pair of “two-wire waveguides”. These wires are laid out on concentric circles with the inner and outer most wires on lower level of the chip, and the middle pair of wires on the top layer (the chip surface).

An optical sensor includes a directional coupler comprising at least a first port, a second port, and a third port. The first port is in optical communication with the second port and with the third port such that a first optical signal received by the first port is split into a second optical signal that propagates to the second port and a third optical signal that propagates to the third port. The optical sensor further includes a photonic bandgap fiber having a hollow core and an inner cladding generally surrounding the core. The photonic bandgap fiber is in optical communication with the second port and with the third port. The second optical signal and the third optical signal counterpropagate through the photonic bandgap fiber and return to the third port and the second port, respectively. The photonic bandgap fiber has a phase thermal constant S less than 8 parts-per-million per degree Celsius.

The invention relates to an automatic guiding system of shield machine based on fiber gyro total station and PSD laser target, comprising fiber gyro total station, PSD laser target, computer of automatic guiding system and back-sight reference prism. The fiber gyro total station comprises fiber gyro north seeker, laser total station and ARM processor. The laser total station emits laser to the back-sight reference prism and PSD laser target so as to measure the distance from fiber gyro total station To back-sight reference prism and PSD laser target. The back-sight reference prism reflects laser emitted by laser total station according to the incident direction. The ARM processor calculates coordinates of laser total station, horizontal azimuth angle of emitted laser and coordinates of laser target. PSD laser target reflects laser emitted by laser total station according to the incident direction and measures the angle between the axis and incident laser and rolling angle and sloping angle of shield machine. The computer of automatic guiding system calculates the horizontal azimuth angle of shield machine. The invention is provided with high accuracy, automatic seeking north and convenient operation. It can be applied in automatic guiding in underground working device such as shield machine.

This invention discloses one triangle wave phase modulation method and device of resonance chamber fiber top, wherein, the laser is connected to first couple device, first phase modulator, second couple device, third couple device, fourth couple device, second phase modulation device and first couple; the first phase modulation and first triangle wave signal generator are connected; the second phase modulation and second triangle signal generator are connected; the second couple device and first photoelectricity, first high speed digital signal processor and laser are connected; the fourth couple device is connected to fourth couple device, second photoelectricity detector, second high speed digital processor; the third couple device is connected to the fiber ring.

In an optical interferometer, polarization dependence attributable to the optical path difference has conventionally been eliminated by inserting a half-wave plate at the center of the interferometer. However, light induced by polarization coupling produced in directional couplers used in the optical interferometer causes interference having different interference conditions from those of the normal light. Polarization rotators that effect any one of 90° rotation and −90° rotation of all states of polarization of incoming light are inserted in the optical interferometer, and thereby the interference conditions of light induced by polarization coupling are made the same as those of the normal light. Each of the polarization rotators is implemented by using two half-wave plates and by varying an angle of combination of these half-wave plates. Alternatively, each of the polarization rotators is implemented through a combination of one half-wave plate and a waveguide having birefringence properties.

The invention discloses a difference double-interference type optical fiber gyroscope based on birefringence modulation. The optical fiber gyroscope comprises a light source, a modulator, a coupler, an optical fiber ring, a polarization beam splitter, a first detector and a second detector, wherein the light source and the modulator are welded at a melting point O1 with an angle of 45 DEG; the modulator and a port A of the coupler are welded at a melting point O2 with an angle of 45 DEG; an end C of the coupler and one end of a polarization-maintaining optical fiber ring are welded at a melting point O3 with an angle of 0 DEG; an end D of the coupler and the other end of the optical fiber ring are welded at a melting point O4 with an angle of 90 DEG; an end B of the coupler and an input end of the polarization beam splitter are welded at a melting point O5 with an angle of 0 DEG; and two output ends of the polarization beam splitter are respectively welded to the first detector and the second detector. According to the invention, closed-loop control of the difference double-interference type optical fiber gyroscope is realized; and a wide-spectrum light source with very weak coherent characteristics is adopted, thereby avoiding strong noise brought by various stray wave interferences which are caused by strong coherent characteristics of a laser light source.

The invention discloses a modulation and demodulation circuit of fiber option gyroscope (FOG) open-loop signals. The circuit adopts a monolithic LVDT integrated circuit (IC) for modulating and demodulating an FOG open-loop signal, generating a sinusoidal signal, synchronously detecting and dividing one odd harmonic amplitude and one even harmonic amplitude and acquiring the tangent value of a mobile signal phase by low-pass filtration. The invention uses the monolithic LVDT IC to realize the four functions, i.e., sinusoidal signal generation of a drive phase modulator, synchronous detection, the elimination of light-source light-intensity fluctuation influence and low-pass filtration and greatly simplify a signal-processing circuit; the monolithic LVDT IC outputs the tangent value of a mobile signal phase so that when the phase increases and trends to pi/2, the tangent value bends upwards, does not trend to saturation and reduces the error of a complementary tangent operation; and a division operation is internally realized by the monolithic LVDT IC so that a digital signal processor at a high price can be replaced by a monolithic computer at a low price for non-linear corrosion.