90 results about "Sagnac effect" patented technology

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).

An integrated module for a fiber optic gyroscope system includes a fiber optic sensing coil arranged to sense rotations about a sensing axis via the Sagnac effect comprises a substrate, an optical waveguide formed on the substrate, a light source comprising a doped waveguide formed on the substrate. The light source and the optical waveguide are arranged to produce counterpropagating light waves in the fiber optic sensing coil. The light source may be formed as a rare earth doped polymer waveguide or as a rare earth doped glass waveguide.

The invention is a compact optical gyroscope based on the Sagnac effect that combines a micro-ring cavity laser comprising a magneto-optical material and a magnetic field to circumvent the lock-in phenomenon at low rates of rotation. The invention also embodies novel processes for breaking lock-in using a transverse Faraday effect.

The invention discloses a chip-type atom gyroscope and a rotation measuring method thereof. The gyroscope comprises an atom chip, a glass vacuum cavity, an ion pump, a current feedthrough device, a vacuum valve and a four-way joint, wherein four openings of the four-way joint are respectively connected with the glass vacuum cavity, the ion pump, the current feedthrough device and the vacuum valve; the atom chip is connected to the glass vacuum cavity; and a wire structure on the atom chip comprises a plurality of wire arrays consisting of wires which are parallel to one another along a direction y, two wires along a direction x and two groups of coplanar microwave waveguides along the direction x. According to the method, three-dimensional atom captivity potential well is generated on the surface of the atom chip, cold atoms are loaded into the captivity potential well, the cold atoms with different internal states are separated from one another and combined together by the two groups of coplanar microwave waveguides when the cold atoms are moved by the wire arrays, and a rotation speed is calculated according to a sagnac effect theory. The gyroscope is convenient to carry, high in sensitivity and wide in application prospect, and the loop area of the gyroscope can be superposed.

The invention provides a simulation method for the digital closed-loop control logic of a fiber-optic gyroscope. The simulation method comprises the following steps: establishing a model and simulating according to the model, wherein a fiber-optic gyroscope closed-loop control logic model comprises a digital demodulation model and a digital controller model, and a closed-loop control logic simulation fiber-optic gyroscope model comprises a Sagnac effect model, a deviation modulation model, a step modulation model and phase modulation model; determining parameters needed by simulation, wherein the parameters comprise a system loop closing cycle, a modulation square wave frequency f, a square wave half-cycle sampling point number and a magnification factor; adjusting the magnification factor of a pre-amplifier module and the magnification factor of a post-amplifier module to realize normal loop closing of the fiber-optic gyroscope model in a simulation process; determining whether the output scale factor of the fiber-optic gyroscope is consistent with a required index or not through the waveform and numerical value of an output signal. By adopting the simulation method, designers do not need to perform detailed coding writing and can put more effort into system design and analysis; the project period can be shortened, the working efficiency is increased, and the product cost is reduced.

The invention provides an angular velocity measuring device based on a tunable optoelectronic oscillator. The angular velocity measuring device comprises a laser source, a first polarization controller, an electro-optic modulating element, an optical circulator, a second polarization controller, a first polarization beam splitter/combiner, a Sagnac ring, a dispersion element, a third polarizationcontroller, a second polarization beam splitter/combiner, a fourth polarization controller, a fifth polarization controller, a first segment of optical fiber, a second segment of optical fiber, a third polarization beam splitter/combiner, a photoelectric detector, a microwave amplifier, and a power divider. According to the angular velocity measuring device, the Sagnac interferometer is embedded into a microwave photonic filter, so that phase change caused by Sagnac effect is converted into the center frequency of the microwave photonic filter, and change of optoelectronic oscillator output microwave signal frequency is induced. The tunable range of the microwave photonic filter is usually at GHz scale, and the optoelectronic oscillator is capable of generating high quality microwave signals, so that the system is capable of increasing angular velocity measuring sensitivity, and widening the dynamic range at the same time.

The invention discloses a multi-loop type photonic band gap optical fiber gyroscope based on reflection. The multi-loop type photonic band gap optical fiber gyroscope comprises a light source, a coupler, a Y waveguide, a photonic band gap optical fiber ring and a detector, wherein the light source and the detector are directly coupled with a tail fiber of the input end of the Y waveguide by a semi-transparent and semi-reflection membrane to realize light splitting; the two output ends of the Y waveguide are directly coupled with the two ends of the photonic band gap optical fiber ring; and the end faces of the output ends of the Y waveguide are covered with reflection membranes. According to the multi-loop type photonic band gap optical fiber gyroscope based on the reflection, the end face reflection between a traditional optical fiber and a photonic band gap optical fiber is utilized, so that a plurality of circulation loops of the gyroscope are realized, and a Sagnac effect is enhanced; and the length of the optical fiber ring is reduced on the premise that the precision is guaranteed, the low cost and miniaturization of the photonic band gap optical fiber gyroscope are easy to realize, and nonreciprocal errors caused by the change of the external environment can be effectively inhibited.

The invention relates to a method for optimizing the dynamic property of an optical fiber gyro, which comprises sequentially connected forward path links: sagnac effect, photoelectric conversion, filtering amplification, AD conversion, cosine response bias modulation and demodulation, first field integral digital storage and digital interception, and sequentially connected backward links: second order integral, D/A conversion power amplification, power amplification, phase modulation and coil delaying. The treatment procedure comprises the following steps: establishing a simplified gyro closed-loop model; establishing a precise gyro closed-loop model; determining gyro stabilization and over modulation conditions; and selecting closed-loop parameters for the optical fibre gyro, and predicting gyro dynamic property through simulation. The method of the invention is reasonable in design, can realize zero bias effect prediction of the gyro during vibration, provides reference for optimizing gyro closed-loop parameters, and improves the dynamic property of the optical fiber gyro.

The invention relates to a phase detection method of a cold atom Bose-Einstein condensation vortex superposed-state gyroscope. Superposed-state vortex light is emitted into a Bose-Einstein condensation state gas atom cluster to enable the Bose-Einstein condensation (BEC) atom cluster to obtain a certain orbital angular momentum, and stable vortex superposed-state matter waves are generated; the BEC atom cluster in a potential well is equivalent to a matter wave interference gyroscope. Atom density distribution of the BEC forms a stable gyroscope pattern; when the system rotates at a certain angular speed, a certain phase is generated due a Sagnac effect; each atom has a fixed scattering effect on photons; after detection light is added, a whole resonance absorption image is detected through a charge coupled device (CCD) and scattering light intensity is calculated through space calculation and time calculation; density distribution of the BEC atom cluster is reckoned so as to obtain phase information; relative light intensity change can be obtained through space subtraction, is used as a gyroscope signal and is used for reckoning a system angular speed, so that the sensitivity on the system angular speed is realized.

Method and apparatus embody a rotation sensor including one or more ring lasers designed to utilize a nonlinear Sagnac effect, a passive waveguide arrangement, and a photodetector arrangement to receive the outcoupled light and to detect rotation of the sensor; wherein these components are arranged into a monolithically integrated optoelectronic integrated circuit on a single substrate. The method and apparatus can include seeding a stable, rotation-insensitive, strong (driving) wave using a single-frequency edge emitting laser monolithically integrated on the same substrate.

The invention relates to a coil of an optical fiber current sensor and the optical fiber current sensor. The coil comprises a first current sensing light path which is wound on a current to be measured and a second current sensing light path which is wound on the current to be measured and is opposite to the first current sensing light path in winding direction. The invention provides the coil of the optical fiber current sensor and the optical fiber current sensor, which are high in sensitivity and precision, are insensitive to vibration as the Sagnac effect can be eliminated, and are insensitive to a temperature as double-light-path sensing is adopted.

The invention relates to a vortex optical gyro. Firstly, with a method using phase modulation according to a vortex light wave function, coupling-state vortex light composed of vortex light having opposite wave front spiral directions and having the orbital angular momentum topological charges of +1 and -1 respectively is generated; according to a sagnac effect, synchronous rotation of a coupling-state vortex light generation system and a to-be-measured object is known to make two beams of vortex light having opposite wave front spiral directions generate an optical path difference related to the rotation speed of the to-be-measured object; the specificity of the vortex light makes the optical path difference reflected in angular frequency movement; an optical path of the vortex light is adjusted to change the propagation direction, then through modulated filtration, the vortex light is received, and a waveform of the vortex light is measured; and through waveform analysis, the angular frequency movement of the superposition-state vortex light is obtained, and angular velocity information of the to-be-measured object is calculated. The vortex optical gyro belongs to the field of new-concept gyro in the inertial technology, and can be applied in the fields of superhigh-sensitivity and miniaturized navigation and positioning in future.

A gyroscope having photonic crystals for sensing rotation uses the Sagnac effect to determine angular motion. The gyroscope comprises a photonic crystal capable of guiding counter-propagating light beams in a closed path. A light source, coupling, and detection apparatus permits detection of phase changes between the counter-propagating beams, thereby permitting measurement of angular rotation. The photonic crystal comprises a periodic structure of pillars and voids which creates a photonic bandgap waveguide within which light waves in the proper wavelength range propagate with low loss.

The invention relates to an optical gyroscope, in particular to a fiber laser gyroscope. It consists of an ultra-narrow linewidth fiber mode-locked laser, a wavelength division multiplexer, a fiber Sagnac loop, a circulator, a polarizer and a detector, and a difference frequency signal processing circuit. It is characterized in that it uses a semiconductor pump with a pigtail Active fiber ring laser with Sagnac effect composed of laser, isolator, wavelength division multiplexer and gain fiber; two sets of fiber coupler, circulator, ultra-narrow linewidth photon injection fiber mode-locking device, polarizer and detector The mode selection filter output system composed of the device forms the optical path scheme of the fiber laser gyroscope. The photon injection fiber mode-locking technology introduced in the present invention can make the gyroscope work stably in the ultra-narrow linewidth single longitudinal mode laser state, thereby obtaining the high-resolution detection result of the angular rate; The difference can automatically eliminate the zone-locking effect of the laser gyro. As a high-precision gyroscope, the invention can be applied to inertial measurement units of aviation, spaceflight, navigation and land weapons.

The present invention discloses an optical fiber gyroscope of North Finder in the teaching experiment of optical fiber gyroscope. The optical fiber gyroscope comprises a signal processing circuit board, a light source, a light source control circuit board, a waveguide, a coupler, a laser pen, a photodetector, a gyroscope frame, an organic glass shield, an upper cover, and a plurality of wire clamps. The organic glass shield is arranged on the upper cover; the upper cover is arranged on the gyroscope frame; the signal processing circuit board, the light source, the light source control circuit board, the waveguide, the coupler, the laser pen and the photodetector are arranged on the gyroscope frame. Based on the demonstration of the teaching experiment, the optical fiber gyroscope aims to show the principles of the North Finder which mainly consists of the optical fiber gyroscope, so that the experimenter can achieve the following purposes: (1) learning about the main physical principles of the optical fiber gyroscope, the Sagnac effect; 2) understanding the principles of the four-position method and the one-element linear regression method, and the basic method of eliminating errors; (3) finding the north by operating the experimental equipment by the students and simultaneously acquiring the latitude of the laboratory and rotation angular velocity of the earth; and (4) facilitating the further understanding of the students about the working principle and application of the optical fiber gyroscope, so that the students can basically understand the working principle of the optical fiber gyroscope, and the basic principles of modulation, demodulation and closed-loop work.

A radio frequency based electronic gyroscope function that may be incorporated in its entirety on a monolithic integrated circuit (IC). The detection and measurement of movement in a particular plane is based on the Sagnac effect as it applies to a radio frequency signal that propagates in two different directions in a loop that may be subject to rotational perturbation. In one embodiment, three mutually perpendicular loops that are incorporated into the same integrated circuit and are used to detect and measure movement in three planes (roll, pitch and yaw) thereby allowing a signal processing unit to quantify a general three dimensional movement. The gyroscope can be incorporated into an IC that is used in portable device, such as a mobile handset, to provide it with inertial navigation and movement detection and measurement capabilities.

The invention discloses an angular displacement optical fiber gyroscope, which comprises an optical path part and a circuit part. The optical path part consists of an optical fiber ring, a Y waveguide, a coupler, an optical source and a detector; in the optical path part, an optical signal generates phase shifting through a Sagnac effect; the phase-shifting signal parasitizes in interference optical intensity and is converted and output as a detector signal (electric signal) by the detector; in the circuit part, the detector signal output by the detector is subjected to signal amplification and conversion through a preliminary amplifier and an analog-to-digital conversion circuit; and the circuit part also comprises a circuit resolving unit logic circuit; the circuit resolving unit logic circuit resolves the rotation angle information of the optical fiber gyroscope through carrying out digital signal demodulation, digital filtering and integral treatment on the amplified and converted detector signal, judges and outputs an angle direction. The angular displacement optical fiber gyroscope has the advantages that a program, logic and the like for processing the signal in the circuit part are innovated and improved, so that the optical fiber gyroscope has an angular displacement output function.

The invention discloses an optical waveguide chip with a micro-optical gyroscope Sagnac effect and a preparation method thereof. The optical waveguide chip comprises a substrate, an SiO2 (Silicon Dioxide) lower cladding layer and an SiO2 core area light guide, wherein the SiO2 core area light guide comprises an input straight waveguide part, two arc-shaped bend waveguide parts, an Achimedean spiral bending waveguide part and an output straight waveguide part; an input straight waveguide part of the SiO2 lower cladding layer and a spiral ring of the Achimedean spiral bending waveguide part are vertically crossed, so as to reduce the loss of an X Achimedean spiral bending waveguide part; two arc bending waveguide parts are oppositely connected, an input direct waveguide terminal and a starting end of the Achimedean spiral bending waveguide part are smoothly connected, and an optimal dislocation offset can be guided on the end plane of a wave guide connecting place, so that the bending loss is less. According to the optical waveguide chip, the sensitivity of the gyroscope can be improved, and the noise of the gyroscope can be reduced.

An apparatus and a method for detecting rotation based on the Sagnac effect is disclosed. Input light having sufficient power is injected into a circulating optical resonator to thereby excite an optomechanical oscillation of the resonator at an instantaneous mechanical angular frequency. Rotation of the circulating optical resonator causes a change in a frequency of the optomechanical oscillation of the resonator, which in turn causes the instantaneous mechanical angular frequency to change. The optomechanical oscillation produces modulation sidebands in the resonating optical field at the instantaneous mechanical angular frequency and harmonics thereof, which are demodulated from the optical frequency by detection in a photodetector. Differences in the instantaneous mechanical angular frequency induced by rotation are detected by processing the photodetector output signal.

The invention provides an angular velocity measuring apparatus and method based on a broadband tunable photoelectric oscillator. The device comprises a light source, a first optical coupler, an adjustable light delay line, a first optical circulator, a second optical circulator, a Sagnac ring, a second optical coupler, a light modulator, a dispersive element, a photoelectric detector, a microwaveamplifier and a power divider. According to the invention, the Sagnac ring is connected between two arms of a mach zehnder interferometer (MZI) by the first optical circulator and the second optical circulator and thus a phase change caused by a Sagnac effect is transformed into a free spectral range (FSR) change of interference signal outputting by the MZI, so that mapping of a frequency change of the microwave signal generated by the photoelectric oscillator is realized. Therefore, the angular velocity of Sagnac ring rotation is obtained by monitoring the frequency change of the output microwave signal of the photoelectric oscillator. With the microwave photon filtering technology, the measurement sensitivity is enhanced and the angular velocity measurement range is extended. Moreover, the ngular velocity measuring apparatus has advantages of simple structure and low cost.

The invention relates to solid-state laser gyroscopes for measuring rotational speeds or angular positions which are used, in particular for aircraft engineering. A gyroscope performances depend on the temperature stability of the scale factor thereof (S) which is 4A/L, wherein L and A are the optical length and the area of the laser cavity, respectively and is a laser emission mean wavelength without the Sagnac effect. Conventionally, for gas lasers, each parameter of the scale factor is selected in such a way that it is temperature independent. The solid state lasers which are very different from the gas lasers are not treatable in the same manner. Said invention offers the laser cavity optical architecture based on the scale factor global conservation, wherein each parameter is temperature variable. An architecture which makes it possible to avoid optical mode hopes and several digital examples proving that inventive principles are applicable to standard materials are also disclosed.

The invention relates to a computational camera method based superposition vortex light Sagnac effect detection device, wherein Sagnac effect is produced by an interference ring formed on a helical wave array of superposition vortex light. The detection device comprises a laser, an attenuation slice, a reflector, a beam expander, an SLM (spatial light modulator), a convex lens, a diaphragm, a convex lens reflector, a charge coupled device (CCD) and an experimental table. Firstly, after the laser produces the Gauss beam, laser power is reduced through the attenuation slice; direction of propagation is changed via a reflector group to increase light spots; expansion of diameter of the laser beam and reduction of divergence angle of the beam are performed through the beam expander; superposition vortex light is modulated via the SLM, to-be-detected angular frequency is coupled to frequency change, and sensitive information content enters the CCD to be observed through a 4f imaging system. The computational camera method based superposition vortex light Sagnac effect detection device is simple in structure and high in flexibility and precision.

The invention provides a sensing optical fiber ring and an all-fiber current transformer. The sensing optical fiber ring comprises a twisted optical fiber, wherein the twisted optical fiber is wound on a coil skeleton in the shape of an '8' to form an optical fiber ring section I and an optical fiber ring section II which are opposite in winding direction, the axis of the optical fiber ring section I is perpendicular to the axis of the optical fiber ring section II, and an included angle between the axis of the optical fiber ring section I and a current wire and an included angle between the axis of the optical fiber ring section II and the current wire are both 45 degrees. The winding area of the optical fiber ring section I equals the winding area of the optical fiber ring section II, and the number of windings of the optical fiber ring section I equals the number of windings of the optical fiber ring section II. On the coil skeleton, the starting point of a starting rotation section and the starting point of a speed reducing rotation section of the twisted optical fiber are located at the same position, and the ending point of the starting rotation section and the ending point of the speed reducing rotation section of the twisted optical fiber are located at the same position. The symmetric center of the '8' is located at the central position of the sensing optical fiber ring. According to the sensing optical fiber ring and the all-optical fiber current transformer, the influence on the measurement of the all-optical fiber current transformer due to the performance of lambada/4 wave plates is avoided, and meanwhile, measurement errors, caused by the Sagnac effect due to vibration, of the all-fiber current transformer are eliminated.