Abstract: A passive ring interferometer sensor includes an electromagnetic ring path configured to receive a pair of electromagnetic waves from an electromagnetic radiation source and to direct the waves to be counter-propagating within the ring path toward respective ends of the path. A combination junction receives the waves from the respective ends and combines the waves to be co-propagating within a coupling path. Polarization elements are configured to set the waves to be mutually co-polarized within the electromagnetic ring path and to be mutually cross-polarized within the coupling path. A detector is configured to receive the mutually cross-polarized waves from the coupling path and to detect second-order coherence. Embodiments can sense rotation rate as fiber-optic gyroscopes or serve as other types of sensors such as gravitational wave sensors. Embodiments may have greatly increased unambiguous range and decreased sensitivity to any centroid wavelength shift.

Abstract: Apparatus and methods demonstrate a chip-scale direct optical to RF link that frequency divides up to 120 GHz optical frequency combs to 10 GHz using harmonic multi-tone injection locking. The embodied invention links widely separated optical frequency combs in the millimeter wave regime (>120 GHz) or THz domain (100s of GHz to THz domain), e.g., microresonator-based frequency combs, which are currently outside of the photo-detection region, into the microwave domain (10s of GHz) where it can be easily photo-detected and controlled. The technique works as a perfect optical divider, using a mode-locked laser and optical injection locking as the technique to phase-lock both lasers.

Abstract: Apparatuses and methods for a four port atomic gyroscope are disclosed. Because of its four ports, a four port atomic gyroscope has an output separate from an input so as to increase sensitivity of the atomic gyroscope. Thus, smaller changes in rotation rate around a center axis of an optical waveguide loop of the four port atomic gyroscope can be detected.

Abstract: A hyperbolic modulation offset reducer circuit for a resonator fiber optic gyro (RFOG) is provided. The circuit includes a first demodulation circuit that is configured to demodulate a received transmission signal from a resonator at twice a sideband heterodyne detection modulation frequency to reject signals due to backscatter. A slave resonance tracking loop of the circuit is coupled to an output of the first demodulation circuit. The slave resonance tracking loop is configured to create an offset frequency signal from the transmission signal that is applied to an optical phase lock loop of a RFOG. A hyperbolic modulator offset control loop is also coupled to the output of the first demodulation circuit. The hyperbolic modulator offset control loop is configured to create a subharmonic common modulation signal from the transmission signal that is coupled to a common phase module in a silicon photonics chip of the RFOG.

Abstract: The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in a fiber coil or a sensing chip having a waveguide coil or ring resonator, where the sending chip is coupled to the front end chip. Strip waveguides are designed to primarily select TE mode over TM mode when laser light is coupled into the integrated photonics chip. A plurality of mode-selective filters, based on multi-mode interference (MMI) filter, a serpentine structure, or other types of waveguide-based mode-selective structure, are introduced in the system architecture. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.

Abstract: A vibration sensing optical fiber sensor is structured to include a probe light supplying section, an optical fiber, a polarimeter for reflected light, and a computing unit. The probe light supplying section generates, as probe light, light pulses that are switched alternately and periodically to orthogonal polarization directions. The probe light is inputted to the optical fiber. The polarimeter for reflected light measures a state of polarization of reflected light that is the probe light that has been reflected by the optical fiber. The computing unit carries out specifying of a position of vibrations by using the differential angular velocity from the state of polarization measured by the polarimeter for reflected light.

Abstract: A resonant fiber optic gyroscope comprises: a ring resonator including a fiber coil fabricated from a first type of hollow core fiber; a light source to produce at least two light beams, wherein a first light beam is configured to travel in a clockwise direction in the ring resonator and a second light beam is configured to travel in a counterclockwise direction in the ring resonator; a filter resonator assembly coupled between the light source and the ring resonator including: at least two short pieces of optical fiber shorter in length than the fiber coil, the at least two short pieces of optical fiber fabricated from the first type of hollow core fiber; and wherein prior to the beams entering the ring resonator, a plurality of reflective devices are configured to condition the beams such that they excite the fundamental mode of the hollow core fiber within the ring resonator.

Abstract: A resonator paradigm, where the resonator structure is made up of a very large number of small, coupled Coriolis sensitive units arranged in a periodic 1D or 2D (and, possibly, in the future, 3D) structure to create a Coriolis-sensitive “fabric” that supports a large number of Coriolis-coupled “supermodes. Such a “fabric” can be shaped into arbitrary “waveguides” that propagate either pulses of excitation that are Coriolis-coupled, thus enabling an acoustic version of a FOG-type gyroscope (where a pulse of excitation travels along a passive waveguide and it's phase/time delay is measured), or support multiple “stationary” Coriolis-coupled vibration modes analogous to optical laser modes in an RLG where counter-propagating modes of oscillation are maintained at constant amplitude via a continuous addition of energy.

Abstract: An imaging system uses polarized light to illuminate the target and then uses a polarization filter to remove the light that is reflected from the target without modification. The target can include one or more anisotropic objects that scatter the light and alter the polarization state of the reflected light and causing it to be selectively transmitted to the imaging device which can record the transmitted light through the filter. The illuminating light can be circularly polarized and the filter can remove the circularly polarized light. The target can include asymmetric nanoparticles, such as nanorods that alter the amplitude or phase of the scattered light enabling pass through the filter to be detected by the imaging device.

Abstract: Provided is a polarization controller. The polarization controller includes a substrate, a first core disposed on the substrate and having a rectangular parallelepiped shape, a first cladding layer configured to cover the first core and the substrate and including a groove parallel to the first core in an edge of an upper end thereof, and a metal pattern disposed in the groove and including a first side surface and a bottom surface, which are adjacent to the first core.

Abstract: 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.

Abstract: Techniques and devices for optical sensing of rotation based on measurements and sensing of optical polarization or changes in optical polarization due to rotation without using optical interferometry.

Abstract: An optical fiber sensor system includes a light source, a modulation unit, an optical coupler, a polarization separator, a first polarization controller optically coupled to the polarization separator, and a first detection unit that includes a first optical detector that receives the first component, converts the first component into a first electrical signal, and detects stress. The first polarization controller controls a polarization state of light input to the polarization separator so that the first electrical signal exhibits a first-order response to the stress.

Abstract: Systems and methods for reducing polarization-related bias errors in RFOGS are described herein. In certain implementations, an RFOG system includes a fiber optic resonator, one or more laser sources, wherein light from the laser sources launches first and second optical beams into the fiber optic resonator in opposite directions, and an electro-optically tunable devices in the resonator path configured to modulate the phase difference between polarization components in the first and second optical beams as the optical beams propagate within the fiber optic resonator. The system further includes at least one photodetector, wherein the polarization components of the first and second optical beams are incident on the photodetector, wherein the at least one photodetector provides an electrical signal, and at least one processing unit configured to receive the electrical signal and calculate a rotation rate for the RFOG and provide a drive signal for the electro-optically tunable device.

Abstract: Methods and systems for a photonically enabled complementary metal-oxide semiconductor (CMOS) chip are disclosed. The CMOS chip may comprise a plurality of lasers, a microlens, a turning mirror, and an optical bench, and may generate optical signals utilizing the lasers, focus the optical signals utilizing the microlens, and reflect the optical signals at an angle defined by the turning mirror. The reflected optical signals may be transmitted into the photonically enabled CMOS chip, which may comprise a non-reciprocal polarization rotator, comprising a latching faraday rotator. The CMOS chip may comprise a reciprocal polarization rotator, which may comprise a half-wave plate comprising birefringent materials operably coupled to the optical bench. The turning mirror may be integrated in the optical bench and may reflect the optical signals to transmit through a lid operably coupled to the optical bench.

Abstract: An optical system is provided having a laser configured to generate light having a first laser spectrum with a first linewidth, a waveform generator configured to produce a noise waveform, and an electro-optic phase modulator in optical communication with the laser and in electrical communication with the waveform generator. The electro-optic phase modulator is configured to receive the light having the first laser spectrum, to receive the noise waveform, and to respond to the noise waveform by modulating the light to produce light having a second laser spectrum with a second linewidth broader than the first linewidth.

Abstract: Systems and methods for dynamic bias offset operation in RFOGs are provided. In certain embodiments, an RFOG system includes a fiber optic resonator; laser sources that launch first and second optical beams into the fiber optic resonator in opposite directions; a first servo loop configured to lock the first optical beam to a resonance frequency, the first servo loop including a modulator that modulates the first optical beam at a first resonant tracking frequency; a second servo loop configured to lock the second optical beam frequency, on average, to a resonance frequency, the second servo loop including a modulator that modulates the second optical beam at a second resonant tracking frequency, wherein the second optical beam is further modulated by a modulation frequency; and a filter configured to attenuate signals that result from the interference of the first and second optical beams.

Abstract: A sensor system provides measurement of building interstory drift based on a laser beam impinging on a discrete diode sensor array. The diode sensor array determines the location at which a projected laser bean strikes the array, which provides a direct measurement of interstory drift. The diode sensor array is a two dimensional array of discrete diodes that allow the location of an impinging laser beam to be very accurately tracked as the beam moves back-and-forth across the diode array. Local rotations of the laser source that result from rotations of structural members (e.g. floor beam rotation) are appropriately corrected for. This allows accurate, dynamic measurements of the interstory drift between two floor levels of a shaking building.

Abstract: In one embodiment, a method is provided. The method comprises generating a waveform; measuring signals representative of angular rotation rate in a linear region of the waveform; and diminishing bias error about at least one of a waveform's maxima and minima.

Abstract: Disclosed is an optical fiber interferometric system including a light source (1), a fiber optic coil (8), a coil splitter (3), a photodetector (2), and a polarization filtering unit. According to an embodiment, the polarization filtering unit includes a first waveguide polarizer (51), at least one second thin-plate polarizer (52) and an optical waveguide section (12), the at least one second polarizer (52) being disposed in the Rayleigh zone between a first waveguide end (21) of the first polarizer (51) and a second waveguide end (22) of the optical waveguide section (12).

Abstract: A system for detecting a structural change to a structure is provided, wherein an exciter is positioned at a first location of the structure to transmit an excitation signal that is based on a reference signal and to apply the excitation signal to the structure. An accelerometer is positioned at a second location of the structure to sense the excitation signal after it has propagated to the second location. The accelerometer outputs an electrical signal that represents seismic activity applied to the structure by the excitation signal. A signal processing component is synchronized with the reference signal and receives the electrical signal. The signal processing component is configured to use the reference signal to extract portions of the electrical signal that are synchronized with the reference signal, and to output phase and amplitude values of the extracted portion.

Abstract: A transmissive photonic crystal fiber ring resonator employing single optical beam-splitter comprises: a first fiber-optic collimator, a second fiber-optic collimator, a first photonic crystal fiber collimator, a second photonic crystal fiber collimator, an optical beam-splitter, and a fixture. The first fiber-optic collimator, the second fiber-optic collimator, the first photonic crystal fiber collimator, the second photonic crystal fiber collimator, and the optical beam-splitter are fixed on the fixture; the fiber pigtails of the first fiber-optic collimator and the second fiber-optic collimator are the input/output ports; the fiber pigtails of the first photonic crystal fiber collimator and the second photonic crystal fiber collimator are connected.

Abstract: A bidirectional optical transmission apparatus includes a first optical waveguide device, a second optical waveguide device, and a polarization-maintaining optical fiber that connects the first optical waveguide device and the second optical waveguide device. A direction of a slow axis of the polarization-maintaining optical fiber with respect to a first substrate at a connecting portion between the first optical waveguide device and the polarization-maintaining optical fiber and a direction of the slow axis of the polarization-maintaining optical fiber with respect to the second substrate at a connecting portion between the second optical waveguide device and the polarization-maintaining optical fiber are substantially orthogonal to each other.

Abstract: In some examples, an accelerometer may self-calibrate while in use by setting a scale factor of the accelerometer to a first value; while the scale factor of the accelerometer is set to the first value, obtaining a first acceleration value; setting the scale factor of the accelerometer to a second value; while the scale factor of the accelerometer is set to the second value, obtaining a second acceleration value; based on the first acceleration value and the second acceleration value, determining a bias correction value; obtaining a third acceleration value; and correcting the third acceleration value based on the bias correction value.

Abstract: Techniques and devices for optical sensing of rotation based on measurements and sensing of optical polarization or changes in optical polarization due to rotation without using optical interferometry. In implementations, a device for optical sensing of rotation can include a detection device that includes: (1) a beam splitter that splits the optical output into four optical beams; (2) four detection modules that receive the four optical beams, respectively, to obtain measurements of four different optical Stokes parameters from the four optical beams, respectively, and (3) a processing unit that processes the measurements of four different optical Stokes parameters to determine a rotation angle of a state of polarization of the optical output and a differential phase shift between the first and the second optical beams caused by a rotation experienced by the optical loop.

Abstract: Advantageously, at least one embodiment comprises a flexible pitch reducing optical fiber array (PROFA) coupler capable of maintaining all channels discretely with sufficiently low crosstalk, while providing enough flexibility to accommodate low profile packaging, and having increased stability with respect to environmental fluctuations, including temperature variations and mechanical shock and vibration, and that is combinable in multiple quantities thereof to form an optical multi-port input/output (IO) interface.

Abstract: Embodiments are provided for an improved 2×1 switch cell design with integrated photodiode for off-state monitoring. In an embodiment, am optical switch comprises a 2×1 multi-mode interferometer (MMI) coupler including two input waveguides jointly coupled to an output waveguide, and a photodetector coupled to an edge of a first waveguide of the input waveguides, and positioned next to a side of the output waveguide. In another embodiment, an optical chip comprises two input waveguides parallel to each other, and an output waveguide coupled to the two input waveguides. The optical chip further includes a photodetector coupled to a first waveguide of the two input waveguides, and positioned next to the output waveguide, and a branch waveguide extending from the first waveguide into the photodetector.

Abstract: A signal processing apparatus includes: a clock generator configured to generate a clock signal having a phase based on a phase of an input signal; a phase modulator configured to shift the phase of the clock signal to generate a phase-shifted clock signal; and a signal synthesizer configured to synthesize the phase-shifted clock signal and the input signal to generate a synthesized signal, wherein the phase modulator is configured to determine a value by which to shift the phase of the clock signal based on an amplitude of the input signal and an amplitude of noise included in the input signal.

Abstract: The invention relates to an integrated optical coupler (1) comprising a substrate (3), at least two planar waveguides (4), which are arranged on or in the substrate (3) and consist of a material having a virtually isotropic refractive index (anisotropy of the refractive index of less than 10?6), and al least three monomode fibers (8, 9, 10) coupled to the planar waveguides (4). One of the monomode fibers (8) is a polarization-maintaining fiber. A fiber optic system according to the invention comprises an integrated optical coupler (1) according to the invention, a light source (21) that is suitable for generating light beams, and a first pigtail fiber (22), which is connected at one end to the light source (21) and at the other end to the polarization-maintaining fiber (8) of the integrated optical coupler (1).

Abstract: The present invention provides an angular velocity detection method adopting a bi-directional full reciprocal coupling optoelectronic oscillator, which is implemented on an optical carrier microwave gyroscope. The optical carrier microwave gyroscope is a bi-directional resonant optical carrier microwave angular velocity measurement device sharing one optical fiber loop. The core of the method lies in that the Sagnac effect is sensed using a bi-directional optical carrier microwave resonant cavity, where the optical carrier microwave resonant cavity employs a coupling optoelectronic oscillator to achieve a bi-directional full reciprocal optical fiber path, and non-reciprocity error of the resonant cavity is eliminated effectively. The angular velocity detection method has features of high-precision, easy implementation and low costs.

Abstract: A fiber optic gyroscope (FOG) is provided. The FOG comprises a depolarizer that receives light from a light source, a multifunction integrated optic chip (MIOC) and a sensing coil coupled to outputs of the MIOC. The FOG also includes a polarizer coupled between an output of the depolarizer and an input of the MIOC. The polarizer mitigates polarization non-reciprocity (PNR) bias error and enhances the polarization extinction ratio (PER) of the FOG.

Abstract: A fiber optic interferometric measurement system includes a light source; first and second optical transmission elements; first and second Sagnac-ring interferometers, respectively, including first and second fiber optic coils, and, respectively, having lengths L1 and L2; and first and second individual integrated optical circuits, respectively, connected to the first and second optical transmission elements, and to the two ends of the first and second optic coils, respectively. The interferometric system includes a multiple integrated optical circuit integrating, on a single substrate, the first and second individual integrated optical circuits, and the difference ?l between the optical length of the first optical transmission elements and the optical length of the second optical transmission elements is higher than the maximum of ?Nb1×L1 and ?NB2×L2, in which ?Nb1 and ?Nb2, respectively, are the group birefringence index difference of the first and second fiber optic coils, respectively.

Abstract: A fiber-optic Sagnac interferometer in a rotation rate sensor comprises a multifunctional integrated optical chip (MIOC) with a MIOC transfer function. A digital filter is connected upstream to the multi-functional integrated optical chip, whose filter transfer function corresponds basically to the inverse MIOC transfer function such that the MIOC transfer function is compensated by the filter transfer function. Corresponding coefficients of the filter transfer function may be determined in a main control loop.

Abstract: This invention revealed and demonstrated a method of measuring and deriving a Jones Matrix of a fiber or fiber component, and to compensate the fiber or fiber component such that the fiber or fiber component plus the compensated optical circuit act as if an Unitary Matrix free space condition. In this way, all compensated fibers or fiber components act the same no matter what their original conditions are. It greatly enhances the fiber or fiber component repeatability and stability throughout the fiber or fiber component production line. The compensated circuit for Unitary Matrix can be applied externally or internally.

Abstract: A method of measuring beat frequency comprises modulating a first optical signal and a second optical signal, wherein the first modulated optical signal includes a first carrier frequency and a first plurality of sideband frequencies and the second modulated optical signal includes a second carrier frequency and a second plurality of sideband frequencies. The method also comprises combining a fraction of the first modulated optical signal with a fraction of the second modulated optical signal into a combined signal and determining a carrier beat frequency. The method further comprises selecting a frequency range from the combined signal; performing a fast Fourier transform (FFT) on an electrical signal representing the selected frequency range; tracking the carrier beat frequency based on the FFT; and outputting a rate signal based on the tracked carrier beat frequency, the rate signal indicating a rotation rate of the resonator fiber optic gyroscope.

Abstract: Accelerometers have a number of wide-ranging uses, and it is desirable to both increase their accuracy while decreasing size. Here, millimeter or sub-millimeter wavelength accelerometers are provided which has the advantage of having the high accuracy of an optical accelerometer, while being compact. Additionally, because millimeter or sub-millimeter wavelength signals are employed, cumbersome and awkward on-chip optical devices and bulky optical mediums can be avoided.

Abstract: A method includes simulating operation of a fiber optic gyroscope during a digital simulation. The simulation includes performing an iterative loop that includes simulating an intensity of light from a fiber coil of the fiber optic gyroscope and simulating operation of one or more control loops within the fiber optic gyroscope using the simulated intensity of the light. The intensity of the light is simulated using a sine/cosine function based on at least one angular rate-related effect injected into the simulation as a Sagnac phase shift. The simulated operation of a first of the one or more control loops attempts to reduce or eliminate the Sagnac phase shift. The method also includes storing, outputting, and/or using results of the simulation. The at least one angular rate-related effect could include rotation of the fiber coil and/or mechanical vibration of the fiber coil.

Abstract: A resonator fiber optic gyroscope (RFOG) is provided. The RFOG includes a fiber coil, first and second lasers, first and second phase modulators, and a common phase modulator. The first laser generates CW input light for propagation in the CW direction of the fiber coil. The second laser generates CCW input light for propagation in the CCW direction of the fiber coil. The first phase modulator modulates the CW input light with modulation frequency f1=(n+0.5)*FSR. The second phase modulator modulates the CCW input light with modulation frequency f2=(m+0.5)*FSR so that overlap of major sidebands is avoided. The phase modulation amplitudes of the first and second modulators substantially suppress the optical carrier components of the CW and CCW input light. The common phase modulator is configured to modulate the CW and CCW input light with a common phase modulation frequency and a common phase amplitude.

Abstract: Systems and methods for sideband heterodyning detection are provided. In certain embodiments a system includes an optical resonator configured to allow light to resonate therein; at least one light source that is controlled to form multiple optical fields, wherein each field is phase or frequency modulated at a common modulation frequency and is at a different frequency. The system also comprises multiple heterodyne modulators that phase or frequency modulate a respective field in the multiple fields at a respective heterodyne frequency to form multiple sidebands, wherein the corresponding heterodyne frequency is different for each heterodyne modulator; at least one coupler that couples the multiple sidebands into the optical resonator; and a feedback control that is configured to detect the multiple sidebands transmitted out of the resonator to create multiple detected sideband signals and adjust frequencies of the plurality of fields based on the multiple detected sideband signals.

Abstract: Systems and methods for a polarization matched resonator fiber optic gyroscope are provided. In one embodiment an RFOG comprises: a light source; a fiber optic ring resonator; a photodetector that outputs an electrical signal that varies as a function of optical intensity; and an input light polarization servo. A light beam from the servo is launched into the resonator ring in a first direction of circulation. The input polarization servo comprises a birefringence modulator that modulates a phase shift between two components of an input polarization state of the light beam at ?m, the modulator is controlled to drive towards zero a 1st harmonic of ?m as measured in the electrical signal. The servo further comprises a tunable ½ waveplate that adjusts an amplitude of the two components of the input polarization state relative to each other. The tunable ½ waveplate is controlled to maximize a peak optical intensity as measured in the electrical signal.

Abstract: A polarized light beam having a coherence length L can be depolarized by splitting the beam into orthogonally polarized sub-beams and delaying one of the sub-beams relative to the other by a length larger than L. This spatial delay is created by splitting the beam in a walk-off crystal and disposing in the optical path of one of the sub-beams a slab of an optically dense material, while allowing the other sub-beam to propagate outside and near the slab. The sub-beams remain parallel to each other, allowing another walk-off crystal to be used to recombine the sub-beams. A dual-core fiber ferrule and a microlens array can be used to combine fiber-coupled output beams of two laser diodes in a single compact walk-off crystal.

Abstract: A dispersion managed interferometric fiber optic gyroscope comprising: a coupler coupled to the broadband light source via a first input fiber; an IOC comprising: a beamsplitter that directs the input signal to a first output and a second output; a combiner configured to combine a first return signal from the first output and a second return signal from the second output into a combined return signal; an integrated optical circuit input coupled to the coupler via a second input fiber; a fiber optic gyroscope sensing coil coupled to a first pigtail fiber and second pigtail fiber, the sensing coil comprising sensing fibers, wherein at least one dispersion slope of at least one of the first input fiber, second input fiber, first pigtail fiber, second pigtail fiber, and the sensing fibers is selected such that the signals at the IOC input has a second order coherence substantially equal to two.

Abstract: A fiber optic interferometric measurement system includes a light source; first and second optical transmission elements; first and second Sagnac-ring interferometers, respectively, including first and second fiber optic coils, and, respectively, having lengths L1 and L2; and first and second individual integrated optical circuits, respectively, connected to the first and second optical transmission elements, and to the two ends of the first and second optic coils, respectively. The interferometric system includes a multiple integrated optical circuit integrating, on a single substrate, the first and second individual integrated optical circuits, and the difference ?l between the optical length of the first optical transmission elements and the optical length of the second optical transmission elements is higher than the maximum of ?Nb1×L1 and ?NB2×L2, in which ?Nb1 and ?Nb2, respectively, are the group birefringence index difference of the first and second fiber optic coils, respectively.

Abstract: A dispersion managed interferometric fiber optic gyroscope comprising: a coupler coupled to the broadband light source via a first input fiber; an IOC comprising: a beamsplitter that directs the input signal to a first output and a second output; a combiner configured to combine a first return signal from the first output and a second return signal from the second output into a combined return signal; an integrated optical circuit input coupled to the coupler via a second input fiber; a fiber optic gyroscope sensing coil coupled to a first pigtail fiber and second pigtail fiber, the sensing coil comprising sensing fibers, wherein at least one dispersion slope of at least one of the first input fiber, second input fiber, first pigtail fiber, second pigtail fiber, and the sensing fibers is selected such that the signals at the IOC input has a second order coherence substantially equal to two.

Abstract: A personnel monitoring system. The personnel monitoring system includes a host node having an optical source for generating optical signals, and an optical receiver. The personnel monitoring system also includes a plurality of fiber optic sensors for converting at least one of vibrational and acoustical energy to optical intensity information, each of the fiber optic sensors having: (1) at least one length of optical fiber configured to sense at least one of vibrational and acoustical energy; (2) a reflector at an end of the at least one length of optical fiber; and (3) a field node for receiving optical signals from the host node, the field node transmitting optical signals along the at least one length of optical fiber, receiving optical signals back from the at least one length of optical fiber, and transmitting optical signals to the optical receiver of the host node.

Abstract: A fiber-optic interferometer comprising an optical fiber wound to form a fiber coil into which two partial light beams of a first light source can be coupled. The Bragg structure is integrated into the fiber coil. Said Bragg structure comprises an optical fiber having a periodically varying refractive index. In a method for determining physical state parameters in the interior of a fiber coil of a fiber optic interferometer information about physical state parameters in the interior of the fiber coil is obtained on the basis of the reflection wavelength of a Bragg structure comprising an optical fiber having a periodically varying refractive index is integrated into the fiber coil.

Abstract: An optical rotation sensor includes a Fabry Perot laser having an active gain medium for generating first and second light beams, a closed optical path through which the first and second light beams counter-propagate and first and second mirrors coupled to respective ends of the closed optical path. The first minor is a ring mirror having a complex valued reflectivity that varies with a rotation rate of a frame within which the optical rotation sensor is placed. A detector is coupled to an output of the Fabry Perot laser to measure an output intensity thereof.

Abstract: A resonator fiber optic gyroscope (RFOG) is provided.

Abstract: A rare-earth-doped-fiber light source with wavelength stability includes a rare-earth doped fiber and an undoped fiber placed in proximity to each other and having the same host material and the same cross-sectional structure, a coupler configured to direct a first portion of pump power from a pump laser to the undoped fiber so the first portion of pump power was twice passed through the coupler; and a wavelength division multiplexer configured to input a second portion of pump power from the pump laser to the rare-earth doped fiber. The rare-earth doped fiber is an active medium for the broadband light source and includes a fiber core doped with rare-earth ions. The undoped fiber includes a rare-earth-dopant-free fiber core. The length of the undoped fiber is one of the same as that of the doped fiber or optimized to match a radiation sensitivity of the doped fiber.

Abstract: A system and method for reducing coherent backscattering-induced errors in an optical gyroscope is provided. A first time-dependent phase modulation is applied to a first laser signal and a second phase modulation is applied to a second laser signal. The phase-modulated first laser signal propagates in a first direction through a waveguide coil and the phase-modulated second laser signal propagates in a second direction opposite the first direction through the waveguide coil. The first time-dependent phase modulation is applied to the phase-modulated second laser signal after the phase-modulated second laser signal propagates through the waveguide coil to produce a twice-phase-modulated second laser signal. The second time-dependent phase modulation is applied to the phase-modulated first laser signal after the phase-modulated first laser signal propagates through the waveguide coil to produce a twice-phase-modulated first laser signal.