525 results about "Fiber loop" patented technology

A method and apparatus for performing refractive index, birefringence and optical activity measurements of a material such as a solid, liquid, gas or thin film is disclosed. The method and apparatus can also be used to measure the properties of a reflecting surface. The disclosed apparatus has an optical ring-resonator in the form of a fiber-loop resonator, or a race-track resonator, or any waveguide-ring or other structure with a closed optical path that constitutes a cavity. A sample is introduced into the optical path of the resonator such that the light in the resonator is transmitted through the sample and relative and/or absolute shifts of the resonance frequencies or changes of the characteristics of the transmission spectrum are observed. A change in the transfer characteristics of the resonant ring, such as a shift of the resonance frequency, is related to a sample's refractive index (refractive indices) and/or change thereof. In the case of birefringence measurements, rings that have modes with two (quasi)-orthogonal (linear or circular) polarization states are used to observe the relative shifts of the resonance frequencies. A reflecting surface may be introduced in a ring resonator. The reflecting surface can be raster-scanned for the purpose of height-profiling surface features. A surface plasmon resonance may be excited and phase changes of resonant light due to binding of analytes to the reflecting surface can be determined in the frequency domain.

A body is configured for alignment to a substrate having an alignment feature. The body includes an alignment structure defining a viewing surface, and a dedicated lens adapted to focus an image of the substrate's alignment feature through an optically-clear material of the body and onto the viewing surface. In the fiber optic context, a lens body is provided for optically coupling a substrate's OED to a corresponding optical fiber. The lens body further includes at least one active lens adapted to cooperate optically with a respective OED. The dedicated lens is positioned externally to any optical path. An optical subassembly includes a substrate having at least one perceptible alignment feature provided in a predetermined spatial relationship to the OED, and a lens body secured to the substrate such that the image of the substrate's alignment feature appears aligned relative to the viewing surface.

A device comprising a fiber grating loop ringdown (FGLRD) system of analysis is disclosed. A fiber Bragg grating (FBG) or Long-Period grating (LPG) written in a section of single mode fused silica fiber is incorporated into a fiber loop. By utilizing the wing areas of the gratings' bandwidth as a wavelength dependent attenuator of the light transmission, a fiber grating loop ringdown concept is formed. One aspect of the present invention is temperature sensing, which has been demonstrated using the disclosed device. Temperature measurements in the areas of accuracy, stability, high temperature, and dynamic range are also described.

The invention provides a simplified multiplexing white light interference fiber sensing demodulating device, which comprises a single-fiber two-way optical transmitting/receiving module, an optical fiber resonant cavity, a single-mode transmission fiber, and an optical fiber sensing array, wherein the single-fiber two-way optical transmitting/receiving module is composed of a semiconductor light source as the transmitting terminal, a semiconductor photodetector as the receiving terminal and related devices packaged together; and an optical fiber annular cavity is composed of an optical fiber coupler, an optical fiber self-focusing lens and a movable corner reflector. The device can achieve enquiry and measurement of a plurality of optical fiber sensors by embedding the single-fiber two-way optical transmitting/receiving module and the optical fiber resonant cavity in the single-mode optical fiber, and has the advantages of simple structure, easy implementation, no length restriction of the transmission cable, no influence caused by the external environment, and good stability and reliability. The device can be used for the measurement of physical quantities such as distributed deformation, strain and temperature, and can be used for multi-task sensing, multi-element sensing, local strain sensing, large-scale deformation sensing, etc.

The invention relates to a magnetic control tunable optical fiber comb filter belonging to the technical fields of optical fiber sensing and optical fiber communication. The magnetic control tunable optical fiber comb filter comprises a broadband light source, an optical fiber coupler, an optical fiber environment, a magnetic field generating unit and a photoelectric detector, wherein the optical fiber environment comprises a left arm optical fiber, a right arm optical fiber and a PCFG (Photonic Crystal Fiber Grating). The magnetic control tunable optical fiber comb filter is characterized in that the PCFG cladding is provided with five large shaddock-form air holes of single-layer structures, and magnetofluid is filled into the large air holes through a capillary phenomenon and changes in the refraction index under the action of a variable magnetic field to change the effective refraction index of a PCFG cladding and cause the wavelength movement of a harmonic peak coupled between a PCFG base mode and a cladding mode so as to realize the tunability as the output characteristics of the filter. Because of different lengths of the left arm optical fiber and the right arm optical fiber in the optical fiber environment, two paths of light signals reflected by the PCFG have a light path difference and are subjected to interferences when returning to the optical fiber coupler so that a comb filter effect is generated in an output spectrum of the filter.

The invention firstly provides a multi-stage control device for the dynamic tension of an optical fiber winding machine. The device comprises a paying-off wheel and a taking-up ring and further comprises a guide wheel A and a guide wheel B. The paying-off wheel, the guide wheel A and the guide wheel B are fixedly arranged in sequence from left to right. The taking-up ring is movably arranged at the tail end of the right side. A tensioning wheel capable of vertically moving is arranged between the guide wheel A and the guide wheel B. The lower portion of the tensioning wheel is sequentially and fixedly connected with a tension and pressure sensor and a micromechanism. The tensioning wheel and the tension and pressure sensor can vertically move at the same time through the micromechannism. The paying-off wheel is connected with a paying-off wheel motor. The micromechanism, the tension and pressure sensor and the paying-off wheel motor are connected with an upper computer. The invention further provides a multi-stage control device for the dynamic tension of the optical fiber winding machine. The multi-stage control technology is adopted, the control precision of the tension of an optical fiber and the quality of an optical fiber loop are improved, it is effectively guaranteed that the optical fiber loop is evenly wound, and the requirement of a high-precision optical fiber gyroscope is met.

The invention relates to a connecting rod for an internal combustion engine, comprising a center rod having a first and a second end, the first end being provided with a big eye and the second end being provided with a connecting piece; wherein the big eye comprises a first and a second cap for taking up a bearing in between, the first cap being arranged on the center rod; at least one endless fiber loop wrapped around the whole connecting rod; and a tensioner arranged over the first cap, the at least one fiber loop being placed between the tensioner and the first cap, the tensioner being connected to the second cap by the fastening elements under assembling together the first and second caps and tensioning the at least one fiber loop.

An apparatus is disclosed for the reception of a surgical instrument inserted through a cannula assembly. An orifice in a seal member defines a central longitudinal axis in general alignment with the cannula assembly. The seal member includes an elastic member for engaging the surgical object about the orifice and forming a fluid-tight interface. A fiber loop is at least partially embedded in the elastic member and serves to compress central portions of the elastic member around the instrument. The fiber loop may form a loop around the orifice and may cooperate with other fiber loops similarly embedded in the seal.

The invention relates to a double waveguide parallel polarization maintaining fiber and a manufacturing method thereof. The double waveguide parallel polarization maintaining fiber comprises two polarization maintaining fibers with the same waveguide structure, and is characterized in that: symmetrical sides of the two polarization maintaining fibers are connected in parallel or connected in parallel into a whole, and the stress zone directions of fiber waveguide of the two polarization maintaining fibers are consistent with the parallel direction or are vertical to the parallel direction; coatings are wrapped outside the two polarization maintaining fibers; and the sections of the coatings have a smooth pancake shape. Two polarization maintaining fiber prefabrication rods are arranged in a fiber drawing furnace in parallel or two fiber drawing furnaces which are arranged in parallel; and the two polarization maintaining fiber prefabrication rods are heated simultaneously, melted in a high temperature and drawn to form fibers. The manufacturing accuracy of a fiber loop used in the field of fiber optic gyros and fiber optical sensors, and the stress and temperature sensitivity of the fiber loop are improved, and the improvement on the process for manufacturing the fiber loop is facilitated.

The invention discloses a separable demoulding skeleton for manufacturing an optic fiber loop of an optic fiber gyroscope, comprising a first installation disc, a second installation disk, and a fan ring consisting of at least two fan blades, wherein, one side of the first installation disc is provided with a hollow screw rod which is vertical to the disc surface, a plurality of location screw holes are uniformly arranged around the hollow screw rod on the first installation disc, at least one first circular groove is arranged around the hollow screw rod on the first installation disc; a screw hole matching with the hollow screw rod is arranged on the second installation disc, at least one second circular groove is arranged around the screw hole on the second installation disc, and the second installation disc is provided with a plurality of fixed screw holes; two sides of the fan ring are respectively provided with flanges matching with the first circular groove and the second circular groove, the fan ring is provided with mounting holes corresponding to the location screw holes for fixing the fan ring on the first installation disc. The invention overcomes the various stress influences brought by the presence of the skeleton in the traditional scheme, and is suitable for preparing optic fiber loops having various widths.

The invention relates to a high-sensitivity micro-nano fiber compound type microcavity biochemical sensor. The biochemical sensor consists of a knot type micro-ring resonant cavity and a compound type microcavity, wherein the knot type micro-ring resonant cavity is made of micro-nano fibers, and the compound type microcavity consists of F-P microcavities formed in a manner that a femtosecond laser acts on two sides of the micro-ring resonant cavity. The manufacture method of the biochemical sensor comprises the following steps of: fusing a normal single mode fiber to prepare the micro-nano fiber, manufacturing two reflection mirrors in the micro-nano fiber by the femtosecond laser, and knotting between the two reflection mirrors, thus finally preparing a micro-nano fiber compound type microcavity formed by a micro-nano fiber F-P cavity and a knot type micro-nano fiber ring cavity. The micro-nano fiber compound type microcavity related to the invention has a huge change slope at a central wavelength position due to a Fano resonance spectral line, the tiny environmental parametric variation can be transformed into detectable intensity variation by a steep slope, and the sensitivity of the biochemical sensor can be greatly improved, so that the fast response speed and high-sensitivity micro-nano order biochemical measurement can be realized.

The invention relates to optical sensors and systems and methods employing the sensors for detecting one or more compounds of interest in a test medium. In one embodiment an optical sensor comprising a long period grating and a solid phase microextraction (SPME) film is exposed to a test medium such that one or more compounds of interest are selectively partitioned into the solid phase microextraction film. At least one optical property of the sensor exposed to the test medium is compared with at least one corresponding optical property of the sensor in absence of the test medium; wherein a difference in the optical property is indicative of one or more compounds of interest in the test medium. The methods and systems may employ long period grating sensors with or without SPME films, and fiber loop ring-down spectroscopy to measure optical properties of the sensor.

An optical fiber vibration sensor includes a light source, an optical receiver, an optical dividing/coupling part, a signal processing unit, and a fiber loop part made of an optical fiber. A part of an optical fiber composing the fiber loop part is installed outside a housing of a main body of the optical fiber vibration sensor and another part of the optical fiber composing the fiber loop part is installed outside the housing as a vibration detecting optical fiber.

An asynchronous metropolitan packet transport ring having guaranteed QoS. Asynchronous packetized data flow in one direction through a fiber optic loop. A number of Metropolitan Packet Switches (MPS) are coupled to the fiber optic loop. An MPS allows packetized data from an upstream MPS to flow to a downstream MPS over a segment of the fiber optic loop. The MPS also puts packetized data onto and pulls packetized data off of the fiber optic loop. Thereby, flows can access the fiber optic loop via the MPS's. The MPS's also regulate the data rates on a per-flow basis according to setup information supplied by a Ring Management System (RMS). If one segment of the fiber loop becomes overly congested, the MPS guarantees quality of service for those flows by deallocating available bandwidth from flows upstream to the point of congestion. Utilization of packet transport ring capacity is optimized by allocating any bandwidth that becomes available to active flows according to a pre-specified weighting scheme.

The optical fiber laser with multiband output includes pump source, light coupler, polarization controller, light splitter, array waveguide grating and light beam splitter connected successively to constitute loop. The present invention realizes the multiband amplification with single pump source by connecting AWG into fiber loop with doped fiber, using the AWG as intracavity light filler to select resonant wavelength and amplify radiation, and coupling the AWG multiplexing end to doped fiber. The device of the present invention has simple and small integrated structure, various light source with different wavelength and wavelength interval may be realized via altering AWG structure parameters, and standard wavelength and wavelength interval of C-band and L-band in ITU-T may be realized reliably.

The invention provides an optical fiber loop framework comprising a framework body the rim of which is provided with an annular groove. A plurality of optical fiber grooves are arranged at the bottom of the groove of the framework body along an optical fiber winding direction; and the distance of the adjacent optical grooves is consistent with the diameter of an optical fiber to be wound. A plurality of positioning bulges and positioning grooves, which are convex and concave alternatively, are arranged on the lateral wall of the framework body along the optical fiber winding direction; and the diameters of the positioning bulges and the positioning grooves are opposite to positions, having equal distanced with the bottom of the groove, on the two lateral walls of the diameter of the optical fiber to be wound in a convex-concave mode. An optical loop winding method using the framework comprises the following steps of: 1) calculating and preparing the optical fiber with enough length and remaining a tail fiber enough; 2) marking the both end points and central point of the optical fiber, and marking symmetrical central points on the outer wall at the right side of the framework; 3) tightly adhering the optical fiber to the inner side of the right wall of the framework, aligning the left and right symmetrical central points of the optical fiber to the symmetrical central points with the symmetrical central point mark on the outer wall of the framework, and winding the optical fiber by using a four-pole symmetrical winding method until the two sections of optical fibers are wound to the respective final points respectively; 4) fixing the tail fiber on the framework; and 5) carrying out later-period curing process.

The invention provides a scanning laser interference type fiber optic acoustic phase-locked detection system and a scanning laser interference type fiber optic acoustic phase-locked detection method,which belong to the technical field of trace gas detection. The system comprises a photoacoustic excitation light source, a light modulator, a photoacoustic cell, a fiber optic microphone, a broad-band scanning laser source, a fiber optic circulator, a high-speed wavelength query module, a phase-locked loop, a square-wave signal generator, a digital signal processor, and a computer. By carrying out synchronous wavelength scanning control and synchronous spectrum sampling control on the broad-band scanning laser source and the high-speed wavelength query module and combining the Fabry-Perot cavity length high-speed synchronous demodulation technique based on a fiber optic scanning laser interferometer with the phase-locked amplification technique, the invention realizes high sensitivity andhighly stable detection on weak photoacoustic signals. The invention can greatly increase the precision and limit sensitivity of photoacoustic spectrometry-based trace gas detection, and provides a highly competitive technical solution for photoacoustic spectrometry-based trace gas detection.

The invention relates to a fiber Sagner loop dynamic weighing sensor. In the sensor, a tail fiber of a light source module is connected with a first port of a fiber circulator; a second port of the fiber circulator is connected with a first port of a fiber coupler; a third port and a fourth port of the fiber coupler are connected to form a loop circuit by fibers; a fiber polarization controller, a fiber protection and enhancement sensing head and a piezoceramics actuator are connected in series to the loop circuit; a third port of the fiber circulator is connected with an input terminal of a first photodetection unit; a second port of the fiber coupler is connected with an input terminal of a second photodetection unit; an output terminal of the first photodetection unit is connected with a data acquisition card; an output terminal of the second photodetection unit is connected with the data acquisition card; the data acquisition card is connected with an input terminal of the piezoceramics actuator to form a feedback loop and connected with a signal processing and displaying system. The fiber Sagner loop dynamic weighing sensor has the characteristics of strong environmental intrusion resisting capacity, high measuring precision and accuracy and wide measuring scope.

The invention discloses a system for realizing multi-machine parallel operation of SVG (Static Var Generator) and a control method thereof. The system comprises multiple SVG devices; each SVG device is provided with a pair of fiber ports respectively used for receiving and sending optical signals; as an annular topological structure is formed by connecting the SVG devices in series and in order through the fiber ports and connecting the head SVG device with the end SVG device, a fiber looped network is formed; and a host computer in the SVG devices transmits an instruction to other slave computers through the fiber looped network so as to control outputting of reactive power which requires compensation. The control method comprises the steps that the SVG device which is configured as the host computer determines a uniform distribution coefficient used for reactive power distribution in real time based on the power which requires compensation; and each SVG device carries out power compensation based on the uniform distribution coefficient and a rated output capacity. The system for realizing multi-machine parallel operation of the SVG and the control method thereof can realize rapid cooperative operation of multiple SVG devices, and have the advantages of simple structure, strong anti-interference ability, high running stability and redundancy rate of the system and the like.

The invention discloses an interference-type closed loop fiber optic gyroscope based on a cyclic multi-loop effect. The gyroscope comprises a light source, a first coupler, a second coupler, a third coupler, a Y waveguide, a fiber loop and a detector. The light source and the A1 end of the first coupler are welded at a welding point O1 in an angle of 0 degree. The B1 port of the first coupler and an input end of the Y waveguide are welded at a welding point O2 in an angle of 0 degree. An output end of the Y waveguide is welded to the B2 end of the second coupler at a welding point O3 in an angle of 0 degree, the other output end of the Y waveguide is welded to the B3 end of the third coupler at a welding point O4. The A2 end of the second coupler is welded to an end of the polarization-maintaining fiber loop at a welding point O5 in an angle of 0 degree, and the A3 end of the third coupler is welded to the other end of the polarization-maintaining fiber loop at a welding point O6 in an angle of 0 degree. The C2 end of the second coupler and the C3 end of the third coupler are welded at a welding point O7 in an angle of 90 degrees. The D1 end of the first coupler and the detector are welded at a welding point O8 in an angle of 0 degree. The interference-type closed loop fiber optic gyroscope achieves the cyclic multi-loop effect of the gyroscope, doubles rotating signals, reduces the length of the fiber loop, and achieves high precision requirements.