Patent application number | Description | Published |
20080203281 | APPARATUS AND METHOD FOR BIOLOGICAL SENSING - A biological agent detector for detecting predetermined biological agents. The biological agent detector includes an optical fiber, a cladding that clads a length of the optical fiber and a bioindicator disposed within the cladding. The biological agent detector also includes a coherent light source that excites the optical fiber and a biological agent signature detector that detects the presence of a biological agent based upon a change in a resonance characteristic of the optical fiber caused by absorption of the predetermined biological agent into the cladding of the fiber. | 08-28-2008 |
20080212104 | Apparatus and method for resonant chemical and biological sensing - Apparatus and method are provided for chemical and biological agent sensing. The sensing apparatus includes a resonator having a resonance frequency. The resonator includes a coil of a photonic crystal fiber. The photonic crystal fiber has a solid region configured to guide a substantially single optical mode of light having an evanescent tail, a first cladding surrounding an exterior of the solid region, and a polymer coating the first cladding. The polymer has an embedded indicator. The first cladding and polymer are together configured to extend a portion of the evanescent tail into the polymer. The resonator is configured to produce a resonance shape centered at the resonance frequency. A predetermined change in the resonance shape or the free spectral range indicates a reaction of the indicator to the agent. | 09-04-2008 |
20090027675 | MOLECULAR DETECTION SYSTEMS AND METHODS - Methods and systems for detecting materials both energetic and non-energetic. An example system passes a sample of fluid through a filter/concentrator (particulate/molecular). Then desorption of the material in the filter/concentrator occurs at a predefined temperature. The desorbed material is analyzed at an optical resonator system to detect presence of a predefined material. | 01-29-2009 |
20090067775 | FIBER OPTIC CHEMICAL SENSOR - Optical systems for sensing chemicals. An example system includes a light source, a light sensor, a processing device in signal communication with the light source and the light sensor, and a fiber optic cable that receives light from the light source and delivers light to the light sensor. The fiber optic cable includes a cladding material that is permeable to a predefined substance and an optical fiber core surrounded by the cladding material. The optical fiber core is a single mode optical fiber having a diameter greater than 30 μm. The optical fiber core includes a hollow center having a diameter between 1-50 μm. The optical fiber core includes a plurality of lengthwise holes positioned to provide single mode light propagation properties. The plurality of lengthwise holes have a diameter between 0.2-4 μm. | 03-12-2009 |
20090175578 | SYSTEM AND METHOD FOR FIBER BASED RESONATOR COUPLING - A fiber optic alignment device on a crystalline substrate support is disclosed. An exemplary embodiment embodied in a resonator fiber optic gyro is fabricated by a process of forming a crystalline substrate support structure operable to support the first end portion of the optical fiber and the second end portion of the optical fiber; forming a first end V-groove portion and a second end V-groove portion in the support structure; physically coupling the first end portion of the optical fiber to the first end V-groove portion; and physically coupling the second end portion of the optical fiber to the second end V-groove portion. | 07-09-2009 |
20090296098 | RELIABLE LOW LOSS HOLLOW CORE FIBER RESONATOR - An optical coupling device for connecting hollow core optical fiber coils in a fiber optic gyro system. An example fiber optic gyro system includes a recirculator or an integrated optics chip, a fiber coil of hollow core optical fiber with first and second ends, and a coupling device that holds an end of the hollow core optical fiber in an enclosed cavity at some predefined distance from the recirculator or integrated optics chip. The coupling device includes a housing for rigidly holding the fiber end in position. The housing includes a cavity that receives the fiber end. | 12-03-2009 |
20090324169 | MICRO-OPTICS PHOTONIC BANDGAP FIBER COUPLER - A resonator sensing device having an optics coupler device for communicating light between light source(s) and sensor(s) and a hollow core fiber resonator. Light from one resonator fiber tip is coupled to a second resonator fiber tip via a graded index (GRIN) lens having the appropriate pitch such that the maximum coupling efficiency is achieved and having two angled surfaces. The angled surfaces are coated with an appropriate coating having a reflectance R in order to achieve the desired degree of coupling. Light reflected by the second angled surface is captured with another lens (such as a microlens) and coupled to a third fiber segment (coupled port). The optical parameters for the GRIN lens and the microlens are tailored to have the least loss. | 12-31-2009 |
20100002239 | RFOG MODULATION ERROR CORRECTION - Systems and methods for performing modulation error correction. An example system applies common phase/frequency modulation to first and second laser beams, a first intensity modulation to the first modulated beam, and a second intensity modulation to the second modulated beam. Signals outputted are demodulated according to the frequency of the common phase/frequency modulation. Then the first of these demodulated signals is demodulated based on the frequency of the intensity modulation of the first beam, and the second of these demodulated signals is demodulated based on the frequency of the intensity modulation of the second beam. Then, rate of rotation is determined based on demodulated signals. Frequencies of the intensity modulations are unequal and not harmonically related, and intensity modulation encodes each light beam with a unique signature. | 01-07-2010 |
20100002283 | KERR EFFECT COMPENSATED OPTICAL RING RESONATOR - Systems and methods for compensating for nonlinear phase shift accumulation in an optical ring resonator. An example method includes sending a first beam in a clockwise direction around the optical ring resonator and sending a second beam in a counterclockwise direction around the optical ring resonator. Then, nonlinear phase shift accumulation of the first and second beams is compensated for within the optical ring resonator. Compensating includes creating a negative Kerr effect phase shift for each beam based on an estimate of accumulated positive Kerr effect. | 01-07-2010 |
20100027023 | APPARATUS AND METHOD FOR SENSING HAZARDOUS MATERIALS - An apparatus and method for sensing hazardous materials utilizes first and second optical fibers and a recirculator coupled to a substrate. The first optical fiber is coupled to the substrate and has first and second opposing ends and a first substance embedded therein. The first substance is reactive to a first hazardous material type. The second optical fiber is coupled to the substrate and has first and second opposing ends and a second substance embedded therein. The second substance is reactive to a second hazardous material type. The at least one recirculator is coupled to the substrate and configured such that when light propagates from one of the ends of at least one of the first and second optical fibers, at least some of the light is directed by the at least one recirculator into the opposing end of the respective optical fiber. | 02-04-2010 |
20100033729 | BIAS-INSTABILITY REDUCTION IN FIBER OPTIC GYROSCOPES - A computer-implementable method of reducing bias instability in a fiber optic gyroscope includes receiving, with a computer, a first data set enabling the computer to generate a model of the gyroscope, including a light source, a photodetector, and a plurality of optical components and fiber sections coupling the light source to the photodetector, and a light signal to be propagated from the light source to the photodetector. The light signal has an associated wavelength spectrum. For each wavelength of the spectrum, the relative lightwave intensity reaching the photodetector is calculated. A signal-wave intensity and a spurious-wave intensity are determined from the calculated relative lightwave intensities. A scale factor is determined from the signal-wave intensity. The spurious-wave intensity is integrated over the wavelength spectrum of the light source to obtain a total spurious-wave intensity. A rate bias error is determined based on the total spurious-wave intensity and the scale factor. | 02-11-2010 |
20100067844 | RADIOLOGICAL AND NUCLEAR OPTICAL SENSOR - Optical systems for sensing radiation emissions from radiological and nuclear matter. An example system includes a light source, a light sensor, a processing device in signal communication with the light source and the light sensor, and a fiber optic cable that receives light from the light source and delivers light to the light sensor. The fiber optic cable includes an optical fiber core region surrounded by a cladding region. The optical fiber is a single mode optical fiber having a mode field diameter greater than 25 μm. The optical fiber cladding region includes a plurality of lengthwise holes positioned to provide single mode light propagation properties. The plurality of lengthwise holes have a diameter between 0.1-5 μm. | 03-18-2010 |
20100128277 | RFOG WITH REDUCED POLARIZATION MODE INDUCED BIAS ERROR - Hollow core fiber RFOG having symmetric M-(or W-)shape, three-(or two-)mirror configurations. These symmetric configurations help to cancel out polarization error induced bias of the RFOG even when light of the unwanted ESOP is present. The RFOG resonator with optical components forming substantially small cross-coupling angles between their polarization axes, and/or with polarizing elements inserted into the resonator, and/or with resonator mirrors having identical reflectivity for light of different polarization states, can effectively reduce the polarization mode induced bias error. | 05-27-2010 |
20100225922 | CAVITY LENGTH MODULATION IN RESONATOR FIBER OPTIC GYROSCOPES - Systems and methods for reducing rotation sensing errors in a resonator fiber optic gyroscope. An example method propagates a primary light wave through a resonator having an optical fiber and a plurality of optical surfaces for directing the light wave exiting a first end of the optical fiber back into an opposite end of the optical fiber. The optical fiber is wound onto a piezo-electric transducer (PZT) tube. A sinusoidal voltage is applied to the PZT tube to modulate a length of a fiber cavity within the optical fiber. The amplitude and frequency of the fiber cavity length modulation is selected to produce a relative phase modulation between the primary light wave and a double-back reflected light wave, such that the rotation sensing errors resulting from double backscatter of light is at a frequency above a frequency band of interest. This allows the associated error to be filtered out of the rotation rate signal. | 09-09-2010 |
20100225923 | RESIDUAL INTENSITY MODULATION (RIM) CONTROL LOOP IN A RESONATOR FIBER-OPTIC GYROSCOPE (RFOG) - Systems and methods for reducing intensity modulation-induced rotation rate measurement error in a resonator optical gyroscope. The method includes tapping an intensity modulated light beam, directing a portion of the tapped light beam toward a photo detector, outputting from the photo detector a signal proportional to the amplitude variation of the light beam, amplifying the signal, and then providing the signal to the intensity modulator as a control input. Intensity modulation-induced error is reduced by an amount proportional to the gain of the feedback loop. | 09-09-2010 |
20100253948 | SYSTEMS AND METHODS FOR RESONATOR FIBER OPTIC GYROSCOPE INTENSITY MODULATION CONTROL - Systems and methods for improved resonator fiber optic gyroscope intensity modulation control are provided. In one embodiment, a resonant fiber optic gyroscope (RFOG) having a residual intensity modulation (RIM) controller comprises: an intensity modulator optically coupled to receive a light beam from a laser source modulated at a resonance detection modulation frequency; an optical tap device optically coupled to the intensity modulator; and a feedback servo coupled to the optical tap device and the intensity modulator, the demodulating feedback servo generating a sinusoidal feedback signal to the intensity modulator. The feedback servo adjusts an amplitude and phase of the sinusoidal feedback signal provided to intensity modulator based on a residual intensity modulation detected by the demodulating feedback servo. | 10-07-2010 |
20100284020 | PHOTONIC CRYSTAL FIBER SENSOR - Apparatus and method for chemical and biological agent sensing. An example sensing apparatus includes a resonator having a resonance frequency. The resonator includes a coil of a photonic crystal fiber. The photonic crystal fiber has a solid region configured to guide a substantially single optical mode of light having, a cladding surrounding an exterior of the solid region, and at least one hollow core within the cladding. The cladding contains at least one hollow core. The photonic crystal fiber is configured to introduce a fluid that may contain an analyte to the hollow core. The photonic crystal fiber is configured so that the light interacts with the fluid. The resonator is configured to produce a resonance signal centered at the resonance frequency. A predetermined change in the resonance signal indicates a presence of a quantity of the analyte in the fluid. | 11-11-2010 |
20100290057 | COMPACT RESONATOR FIBER OPTIC GYROSCOPES - Substantially symmetric RFOG configurations for rotation rate sensing using two input/output coupling components. Configurations are disclosed where optical coupling components handles both input and output lightwaves. Reducing the number of input/output coupling components while maintaining a substantially symmetric configuration for the CW and CCW beam reduces losses, prevents realization of bias errors due to asymmetric light paths in the resonator, and produces better signal to noise performance. In addition, the invention discloses systems integrating multiple functions into compact micro-optic devices that are easier to fabricate and package, leading to compact RFOGs with reduced cost and improved manufacturability. | 11-18-2010 |
20100309473 | FIBER OPTIC CURRENT SENSOR AND METHOD FOR SENSING CURRENT USING THE SAME - An apparatus and method for sensing current. The apparatus includes an optical fiber having first and second opposing ends, a recirculator configured such that when light propagates from the respective first and second ends of the optical fiber, at least some of the light is reflected, directed or passed by the recirculator into the respective opposing ends of the optical fiber to propagate through the optical fiber and form an optical loop having an opening there through. | 12-09-2010 |
20100316332 | BIAS-INSTABILITY REDUCTION IN FIBER OPTIC GYROSCOPES - Apparatus for providing Bias-Instability reduction in Fiber Optic Gyroscopes are provided. In one embodiment, an optical circuit for a fiber optic gyroscope having a broadband light source and an optical fiber loop comprises: a PM fiber of length v; an IOC coupled to the PM fiber via a pigtail of length d | 12-16-2010 |
20110019198 | RESONATOR FIBER OPTIC GYROSCOPE (RFOG) WITH REDUCED BIAS ERROR FROM HIGH ORDER SPATIAL MODES - Multiple resonator fiber optic gyroscope (RFOG) configurations comprising one or more mode filters inside the resonator are adopted to effectively suppress unwanted high order spatial modes which can be a significant source of gyro bias errors. The resonator comprises at least a loop fiber, either two or more in/out coupling elements, and connectors that link elements into a circulating loop. Directional elements may be used to separate output light from input light in some of the embodiments. In all embodiments, mode filters are placed in the resonator to guarantee that the light reaching the photodetector is filtered by at least one mode filter in the resonator at least once. The mode filters may contain both spatial mode filters (such as single mode fibers or waveguides) and polarization mode filters (such as polarizing elements) so that both spatial and polarization mode filtering can be implemented simultaneously. | 01-27-2011 |
20110026870 | PHOTONIC CRYSTAL FIBER SENSOR - Systems and methods for sensing a target analyte. An example sensor includes a tunable light source that provides a substantially single optical mode of light, a detector, a processor, and a resonator. The resonator resonates light provided by the light source at a predefined frequency. The resonator includes a photonic crystal fiber having a solid region that guides a substantially single optical mode of light and at least one hollow channel adjacent to the solid region. The hollow channel receives a fluid from an external source. The hollow channel is coated with a film having a material that is reactive with the target analyte in a manner that changes the optical properties of the film. The detector detects light from the resonator. A predetermined change in the detected signal as determined by the processor indicates presence of the target analyte. The material in the film is reversible. | 02-03-2011 |
20110037985 | RESONATOR OPTICAL GYROSCOPE HAVING INPUT BEAM MODULATION OPTIMIZED FOR HIGH SENSITIVITY AND LOW BIAS - Systems and methods for optimizing input beam modulation for high gyro sensitivity and low bias errors. The present invention is a resonator optical gyroscope having an optimized phase-modulation amplitude (frequency) for a selected modulation frequency (amplitude) that maximizes the gyro signal-to-noise (S/N) sensitivity. For selected values of the phase modulation amplitude, the polarization cross-coupling induced intensity modulation can be nulled. By setting the phase modulation amplitudes substantially close to these nulling points (e.g. M=3.832 or 7.016 radians, which causes the first order Bessel function to be zero J | 02-17-2011 |
20110141477 | LIGHT-PHASE-NOISE ERROR REDUCER - A resonator gyroscope comprises a reference laser generator to produce a reference light; a first slave light source to produce a first slave light locked to the reference light; a second slave light source to produce a second slave light locked to the reference light; a first optical filter cavity coupled to at least one of the first and second slave light sources to filter out high-frequency fluctuations in the respective first and second slave lights; a resonator coupled to said first and second light sources, the resonator having first and second counter-propagating directions and resonance tracking electronics coupled to the resonator to generate a first beat frequency, a second beat frequency, and a third beat frequency; wherein the rotational rate of the resonator gyroscope is a function of the first, second and third beat frequencies. | 06-16-2011 |
20110292396 | SYSTEM AND METHOD FOR ENHANCING SIGNAL-TO-NOISE RATIO OF A RESONATOR FIBER OPTIC GYROSCOPE - A resonator fiber optic gyroscope includes a sensing resonator having a first resonance frequency for a first laser beam propagation direction and a second resonance frequency for a second laser beam propagation direction; an intensity modulator coupled to an output of the sensing resonator and configured to modulate the intensity of a signal output from the sensing resonator, wherein the intensity modulator modulates the output signal at an intensity modulation frequency; and resonance tracking electronics coupled to an output of the intensity modulator and configured to demodulate the intensity modulated signal output from the intensity modulator at a resonance tracking modulation frequency to produce a first demodulated signal; the resonance tracking electronics further configured to demodulate the first demodulated signal at the intensity modulation frequency, wherein the intensity modulation frequency is different from the resonance tracking modulation frequency. | 12-01-2011 |
20110295511 | APPARATUS AND METHOD FOR DETECTING THE PRESENCE OF AN AGENT - An apparatus and method for detecting an agent utilizes a substrate, a waveguide on the substrate, a light source, a photo-detector, an optical coupler on the substrate, and a processor. The light source is configured to emit light into the waveguide. The photo-detector is configured to detect light. The optical coupler is configured to direct a first portion of light propagating from the waveguide towards the photo-detector and to direct a second portion of the light propagating from the waveguide back into the waveguide. The waveguide and the optical coupler at least partially form a resonator. A substance is at least one of embedded within the waveguide and adjacent to the waveguide. The substance is reactive to the agent. The processor detects a change in a resonance lineshape of the resonator caused by the reaction of the substance to the agent. | 12-01-2011 |
20120007584 | FIBER CURRENT SENSOR WITH REDUCED TEMPERATURE SENSITIVITY - A sensor head assembly is provided, comprising a quarter wave device having shape-induced-birefringence and a sensing coil coupled to the quarter wave device and operable to wind around a current conductor. The quarter wave device converts linearly polarized light from a polarization maintaining fiber to circularly polarized light. | 01-12-2012 |
20120057167 | RFOG WITH OPTICAL HETERODYNING FOR OPTICAL SIGNAL DISCRIMINATION - A RFOG comprises a reference laser configured to produce a reference laser beam; a first laser source configured to produce a first laser beam; a second laser source configured to produce a second laser beam; a sensing resonator coupled to the first and second laser sources such that the first and second laser beams propagate through the sensing resonator in first and second directions, respectively; resonance tracking electronics configured to generate first and second control signals that indicate when the first and second laser beams, respectively, are off resonance; first and second optical combiners configured to beat the first and second outputs of the sensing resonator with the reference laser beam creating first and second beat signals, respectively; wherein the resonance tracking electronics is configured to discriminate between at least one rotation-sensing error and the first and second outputs of the resonator based on the first and second beat signals. | 03-08-2012 |
20120224167 | APPARATUS AND METHOD FOR CHEMICAL, BIOLOGICAL AND RADIOLOGICAL AGENT SENSING - Apparatus and method for chemical, biological and radiological agent sensing. The sensing apparatus includes a plurality of resonators each having a resonance frequency and an optical fiber coil. The optical fiber coils have cladding and an indicator embedded in the cladding that reacts to an agent (chemical or biological substance) or a dopant that darkens with radiation. The resonator circulates light through the coil and produces a resonance shape centered at the resonance frequency and measured via the input light. A predetermined change in the resonance shape indicates a presence of the agent in the environment. | 09-06-2012 |
20120300198 | FREQUENCY STABILIZED LASER SYSTEM - A laser stabilization system includes laser source having first and second ends; first waveguide portion having first and second ends, first end of first waveguide portion coupled to first end of laser source; second waveguide portion having first and second ends, first end of second waveguide portion coupled to second end of laser source; micro-cavity coupled between second end of first waveguide portion and second end of second waveguide portion, micro-cavity having resonant frequency; and electronic locking loop coupled between micro-cavity and laser source, wherein electronic locking loop electronically locks laser source to resonant frequency of micro-cavity; wherein first waveguide portion is optical locking loop coupled between micro-cavity and laser source, wherein optical locking loop optically locks laser source to resonant frequency of micro-cavity; micro-cavity stabilization loop coupled with micro-cavity, wherein micro-cavity stabilization loop stabilizes resonant frequency of micro-cavity to reference frequency; and output for outputting light from system. | 11-29-2012 |
20120307251 | HIGH PERFORMANCE HOLLOW-CORE OPTICAL-FIBER FILTER FOR OPTICAL ROTATION SENSING - A hollow-core optical-fiber filter is provided. The hollow-core optical-fiber filter includes a hollow-core optical fiber having a first end-face and an opposing second end-face. The first end-face and the second end-face set a fiber length. The hollow-core optical-fiber filter also includes a first reflective end-cap positioned at the first end-face and a second reflective end-cap positioned at the second end-face. When an optical beam from a laser is coupled into one of the first end-face or the second end-face, an optical output from the opposing end-face has a narrow linewidth and low frequency noise fluctuations. | 12-06-2012 |
20120307253 | OPTICAL FILTERING FOR RESONATOR-FIBER-OPTIC GYROSCOPES - An optical-fiber filter is provided. The optical-fiber filter includes an optical fiber having a first end-face and an opposing second end-face. The first end-face and the second end-face set a fiber length. The first end-face and the second end-face are coated with reflective coatings. When an optical beam emitted from a laser is coupled into one of the first end-face or the second end-face, an optical beam output from the opposing end-face has a narrow linewidth and low frequency noise fluctuations. | 12-06-2012 |
20130057870 | SYSTEMS AND METHODS FOR RESONATOR FIBER OPTIC GYROSCOPE INTENSITY MODULATION CONTROL - Systems and methods for improved resonator fiber optic gyroscope intensity modulation control are provided. In one embodiment, a resonant fiber optic gyroscope (RFOG) having a residual intensity modulation (RIM) controller is provided. The controller includes an intensity modulator optically coupled to receive a light beam from a laser source modulated at a resonance detection modulation frequency, and an optical tap device optically coupled to the intensity modulator. The controller also includes a feedback servo coupled to the optical tap device and the intensity modulator, the demodulating feedback servo generating a sinusoidal feedback signal to the intensity modulator. The feedback servo adjusts an amplitude and phase of the sinusoidal feedback signal provided to intensity modulator based on a residual intensity modulation detected by the demodulating feedback servo. | 03-07-2013 |
20130107271 | SYSTEM AND METHOD FOR REDUCING ERRORS IN A RESONATOR FIBER OPTIC GYROSCOPE | 05-02-2013 |
20130271770 | RESONATOR FIBER OPTIC GYROSCOPE UTILIZING LASER FREQUENCY COMBS - A resonator fiber optic gyroscope comprises a first light source having a first frequency comb spectrum, and a second light source having a second frequency comb spectrum. A first filter is in optical communication with the first light source and configured to pass a first frequency comb portion. A second filter is in optical communication with the second light source and configured to pass a second frequency comb portion. A resonator is in optical communication with the first and second filters. The free spectral range values of the first and second frequency comb portions are adjusted to be an odd integer multiple of the free spectral range value of the resonances of the resonator. The second frequency comb portion is spectrally separated apart from the first frequency comb portion by a multiple of the free spectral range value of the resonances plus a frequency value proportional to rotation rate. | 10-17-2013 |
20140044142 | LASER WITH TRANSMISSION AND REFLECTION MODE FEEDBACK CONTROL - One embodiment is directed towards a stabilized laser including a laser to produce light at a frequency and a resonator coupled to the laser such that the light from the laser circulates therethrough. The laser also includes Pound-Drever-Hall (PDH) feedback electronics configured to adjust the frequency of the light from the laser to reduce phase noise in response to light sensed at the reflection port of the resonator and transmission port feedback electronics configured to adjust the frequency of the light from the laser toward resonance of the resonator at the transmission port in response to the light sensed at the transmission port of the resonator, wherein the transmission port feedback electronics adjust the frequency at a rate at least ten times slower than the PDH feedback electronics. | 02-13-2014 |
20140049780 | LOW NOISE RESONATOR FIBER OPTIC GYRO - A low-noise resonator fiber-optic gyroscope is provided. The low-noise resonator fiber-optic gyroscope includes at least one laser to output a reference optical beam, a first-optical-beam frequency controller to modulate the first optical beam at a first-modulation frequency, a second-optical-beam frequency controller to modulate the second optical beam at a second-modulation frequency to form a second-frequency-modulated optical beam, a fiber resonator having a counter-clockwise-input end configured to input the first-frequency-modulated optical beam and the clockwise-input end configured to input the second-frequency-modulated optical beam; a first-frequency demodulator to demodulate an optical beam output from the clockwise-input end of the fiber resonator; and a second-frequency demodulator to demodulate an optical beam output from the counter-clockwise-input end of the fiber resonator. The first-modulation frequency and the second-modulation frequency are adjusted so that sideband noise spectrum centered on the first and second modulation frequencies are from each other. | 02-20-2014 |
20140152994 | OPTICAL FREQUENCY COMB STIMULATED BRILLOUIN SCATTERING GYROSCOPE - Systems and methods for measuring rotation using an optical frequency comb stimulated Brillouin scattering gyroscope are provided. In certain embodiments, a system comprises a light source that produces a multiple-frequency light beam based on an optical frequency comb; and an optical fiber resonator coupled to the light source, the multiple-frequency light beam propagating in a first direction within the optical fiber resonator, wherein the multiple-frequency light beam generates stimulated Brillouin scattering (SBS) for a frequency, wherein the Brillouin scattering generates an SBS light beam to propagate in a second direction, the first direction being opposite in direction to the second direction. The system also comprises a servo to control the frequencies of the optical frequency comb to lock a plurality of component frequencies on resonance peaks of the optical fiber resonator; and a mixer that determines a frequency difference between the SBS light beam and the multiple-frequency light beam. | 06-05-2014 |
20140204387 | NARROW BANDWIDTH REFLECTORS FOR REDUCING STIMULATED BRILLOUIN SCATTERING IN OPTICAL CAVITIES - An optical-fiber filter system to narrow a linewidth and to reduce noise fluctuations of an optical beam is provided. The optical-fiber filter system includes an optical fiber having a first end-face and an opposing second end-face, the first end-face and the second end-face setting a fiber length; a fiber Bragg grating having a first reflectivity positioned at the first end-face; and a reflector having a second reflectivity positioned at the second end-face. When the optical beam at a first frequency is coupled from a laser into one of the first end-face or the second end-face, a resonant cavity is established at the first frequency between the fiber Bragg grating and the reflector while Brillouin scattered light shifted from the first frequency within the optical fiber is transmitted through the fiber Bragg grating. | 07-24-2014 |
20140211211 | RFOG WITH OPTICAL HETERODYNING FOR OPTICAL SIGNAL DISCRIMINATION - In one embodiment a system including a resonator fiber-optic gyroscope configured to measure rotation rate is provided. The resonator fiber-optic gyroscope includes a sensing resonator have a first resonance frequency for a first laser beam propagation direction and a second resonance frequency for a second laser beam propagation direction, an optical mixer coupled to an output of the sensing resonator and configured to mix an output of the sensing resonator with a reference laser, wherein the optical mixer outputs a beat signal, and a resonance tracking electronics coupled to the optical mixer. The resonance tracking electronics are configured to demodulate the beat signal at a frequency offset to produce first in-phase and quadrature demodulated information, generate R-squared information from a sum of squares of the first in-phase and quadrature demodulated information, and demodulate the R-squared information at a resonance tracking modulation frequency. | 07-31-2014 |
20140240712 | METHOD AND SYSTEM FOR DETECTING OPTICAL RING RESONATOR RESONANCE FREQUENCIES AND FREE SPECTRAL RANGE TO REDUCE THE NUMBER OF LASERS IN A RESONATOR FIBER OPTIC GYROSCOPE - A resonator fiber optic gyroscope (RFOG) is provided. The RFOG includes a gyroscope resonator having a clockwise input port and a counter-clockwise input port; a first laser configured to couple a clockwise optical beam into to the clockwise input port; a clockwise Pound-Drever-Hall modulation generator to modulate the clockwise optical beam with a resonance tracking modulation before the clockwise optical beam is coupled into the clockwise input port; bias correction electronics; FSR-detection-and-servo electronics including a switch communicatively coupled to the clockwise Pound-Drever-Hall modulation generator; a clockwise transmission detector configured to receive an optical beam output from the counter-clockwise input port and output signals to the bias correction electronics and the FSR-detection-and-servo electronics; and a second laser configured to couple a counter-clockwise optical beam into to the counter-clockwise input port, wherein the FSR of the gyroscope resonator is measured based on the Pound-Drever-Hall modulation of the clockwise optical beam. | 08-28-2014 |
20150015892 | RFOG WITH LOW CHROMATIC DISPERSION - One embodiment is directed towards a resonator fiber optic gyroscope (RFOG) including a resonator, one or more light sources coupled to the resonator, and resonance tracking electronics coupled to the resonator. The one or more light sources are configured to produce at least two light beams for input into the fiber coil, the at least two light beams including a first light beam at a first frequency and a second light beam at a second frequency, the first and second frequencies locked to nearby resonance modes of the resonator. The resonance tracking electronics are configured to process output light from the resonator and generate a signal therefrom, the signal indicative of a rotation rate of the resonator. The fiber coil has approximately zero total accumulated chromatic dispersion at the first frequency and the second frequency of the first light beam and the second light beam. | 01-15-2015 |
20150070707 | LASER WITH TRANSMISSION AND REFLECTION MODE FEEDBACK CONTROL - One embodiment is directed towards a stabilized laser including a laser to produce light at a frequency and a resonator coupled to the laser such that the light from the laser circulates therethrough. The laser also includes Pound-Drever-Hall (PDH) feedback electronics configured to adjust the frequency of the light from the laser to reduce phase noise in response to light sensed at the reflection port of the resonator and transmission port feedback electronics configured to adjust the frequency of the light from the laser toward resonance of the resonator at the transmission port in response to the light sensed at the transmission port of the resonator, wherein the transmission port feedback electronics adjust the frequency at a rate at least ten times slower than the PDH feedback electronics. | 03-12-2015 |