| 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 |
