534 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 mine communication system, in particular to an emergency communication support system of coal mines. The emergency communication support system comprises an integrated command rescue call center server, an IP (Internet Protocol) telephone switchboard and an voice gateway, which are interactively connected through Ethernet, wherein the voice gateway is simultaneously connected to a dispatching switchboard, an integrated IP voice access gateway for mine is adopted as the voice gateway, a 32-bit embedded microprocessor is adopted for the voice access gateway, a protocol conversion address of the microprocessor is connected with a system interface module, a serial port of the microprocessor is connected with a field bus protocol conversion module, the field bus protocol conversion module is connected with an underground dispatching amplified phone, an MAC (Media Access Control) address of the microprocessor is connected with a network module, and the microprocessor is connected with an Ethernet switchboard through the network module. The microprocessor is provided with a corresponding data interface for connecting an optical fiber transmission module, the microprocessor is accessed to an underground industrial optical fiber ring net through the optical fiber transmission module, and the underground loud-speaking phone is accessed to the underground industrial optical fiber ring net through a converter. According to the mine communication system disclosed by the invention, a difficult problem of the speed bottleneck in the wide-band network underground communication of a mine area is solved, and a way is paved for networking and informatizing of a mine monitoring system.

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.

The invention discloses a fiber-optic gyroscope which comprises a wide spectrum light source, an optical detector, a 2*2 coupler, an integrated optic modulator, a first polarization-maintaining beam splitter, a second polarization-maintaining beam splitter and a fiber loop, wherein the 2*2 coupler is used for splitting light from the wide spectrum light source, then enabling the split light to enter the integrated optic modulator, and transferring an interfered optical signal into the optical detector in split beams; the integrated optic modulator is used for polarizing and splitting beams of a light path, fast axis branches and slow axis branches of the first polarization-maintaining beam splitter and the second polarization-maintaining beam splitter are coupled with a fast axis of a tail fiber of the integrated optic modulator, the first branch of the integrated optic modulator is in countershaft welding with the fast axis branch of the first polarization-maintaining beam splitter, the second branch of the integrated optic modulator is in countershaft welding with the slow axis branch of the second polarization-maintaining beam splitter, the slow axis branch of the first polarization-maintaining beam splitter is in countershaft welding with the fast axis branch of the second polarization-maintaining beam splitter, and single-ended tail fibers of the first polarization-maintaining beam splitter and the second polarization-maintaining beam splitter are respectively in countershaft welding with two tail fibers of the 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.

A fiber optic cable includes: a plurality of optical fibers; a tube circumferentially surrounding the optical fibers, the tube being formed of a first polymeric material; an armor circumferentially surrounding and fixed relative to the tube, the armor being formed of a metallic material; and a jacket circumferentially surrounding the armor, the jacket being formed of a second polymeric material. In this configuration, the cable can provide the requisite mechanical, electrical, handling and connectorizing properties for use in applications such as pavement crossings.

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.

A Fiber-optic current sensor for sensing electric current carried in an electric conductor (18). Its optical section comprises: a light source (1); a directional coupler (2) with two ports (2A, 2B) of two arms each; a radiation polarizer (3); a polarization modulator (4); a fiber line (17) coupled to a current-sensing fiber loop (11); a mirror (10); and a photodetector (22). The first port of the coupler (2) is coupled to the light source (1) and to the photodetector (22). Its second port is coupled via the radiation polarizer (3) to the polarization modulator (4). The polarization modulator comprises a magneto-sensitive element (5), around which a solenoid (6) is wound. The fiber loop (11) comprises a magneto-sensitive optical fiber with embedded linear birefringence. An electronic section comprises a signal generator (21) which drives the solenoid (6); and a signal processing unit which receives the optical signal from the photodetector (22).

In one of embodiments of passive polarizing fiber optic gyroscope and current sensor, the core is a 3X3 ''round''polarization maintaining optic fiber coupler composed of ''round'' polarization maintaining fiber coupler. The coupler realizes light splitting and passive polarization effects simultaneously in Sagnac interference sensor optic fiber loop. A variable 3X3 hybrid optic fiber coupler is composed by two linear polarization maintaining optic fibers and a regular single mode optic fiber, wherein the tail fiber of the two linear polarization maintaining optic fibers are connected in interference optic fiber loop based on the linear polarization maintaining optic fiber, the two ends of the single mode optic fiber are cut into short sections by diagonal angles, in order to form matching end face on the two ends. In other embodiment of the passive polarizing fiber sensor, the core is an integrated Faraday rotator, comprising accurate magnetic-optic 45 degree rotation unit, of which one end is connected with a one-quarter glass of ''zero-to-rapid'' optic fiber, other end is connected with a one-quarter glass of ''rapid-to-zero'' optic fiber. The main merit of the passive polarization comprises: simple structure, working stability without manually tuning.

The invention relates to a double-C-type cavity-based sensitive membrane embedded optical fiber hydrogen sensor. The double-C-type cavity-based sensitive membrane embedded optical fiber hydrogen sensor is characterized by comprising a broadband light source, a spectrum analyzer, a single-mode fiber, a circulator and a double-C-type hydrogen sending head; PDMS (polydimethysiloxane) separates a hollow-core fiber into two C-type cavities, one of the C-type cavity forms an interference structure, and the other C-type cavity is embedded with hydrogen sensitive materials to serve as a sensing area.When the concentration of hydrogen rises, Pt / WO3 power reacts with the hydrogen to produce heat, the volume of a PDMS membrane can be increased to lead to movement of an interference spectrum, so thatby detecting the change in interference wavelength, the concentration of the hydrogen can be detected. The double-C-type cavity-based sensitive membrane embedded optical fiber hydrogen sensor solvesthe shortcomings that existing optical fiber hydrogen sensors are large in sensing area, inappropriate to remove control, prone to leading to falling-off of hydrogen sensing materials and complex to manufacture, and meanwhile, is simple in structure and manufacturing, flexible in operation, compact in sensing structure, small in size and applicable to long-term utilization.

The invention relates to a tunable narrow-linewidth fiber laser based on an interval tunable phase shift fiber gratings. The tunable narrow-linewidth fiber laser based on the interval tunable phase shift fiber gratings comprises a laser device (LD), a WDM coupler, an erbium-doped fiber loop, an optical isolator, a circulator, the fiber gratings, a phrase shift fiber grating tuner, an optical coupler, a wavelength meter, an input and control circuit and an output optical coupler, wherein the WDM coupler, an erbium-doped fiber, the optical isolator, the circulator, the phrase shift fiber grating tuner and the optical coupler form an loop cavity; the circulator, the fiber gratings and the phrase shift fiber grating tuner form an adjustable filter inside the cavity. Phase shift amount of the phrase shift fiber gratings is changed by changing the length of an air gap between the two fiber gratings so that tuning of output laser wavelength can be achieved. According to the tunable narrow-linewidth fiber laser based on the interval tunable phase shift fiber gratings, the tunable phase shift fiber gratings, the optical coupler, the wavelength meter, the input and control circuit and the output optical coupler form an input and feedback control loop, the needed laser wavelength is obtained through feedback control, and stability of the laser output wavelength is ensured.

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.

The invention discloses a reflection-type Sagnac interference fiber current sensor. The sensor comprises: a broadband light source, a fiber polarizer, a fiber polarization analyzer, a lithium niobate multifunctional integration device, a fiber loop device, a polarization-maintaining transmission cable, a quarter wave plate, a sensing fiber, a photoelectric detector and a signal processing unit. The lithium niobate multifunctional integration device, which is formed by two polarization beam splitters, is a Mach-Zehnder phase adjusting system. The structure can realize passive bias and can realize active modulation. By using the sensor of the invention, technical difficulty of an active modulation scheme of the interference fiber current sensor can be substantially reduced. Simultaneously, unification of an optical path structure of the two schemes: the passive bias of the fiber current sensor and the active modulation can be realized.

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.

An asynchronous metropolitan packet transport ring having per-flow 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 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.

A system and method for a structure monitoring and locating a disturbance event is disclosed. The system includes a compact transceiver chip sending optical signals in three optical fibers that encompass the monitored structure appropriately. The fiber arrangement has different density in different parts of the monitored structure, such as, for example, critical places in the structure may have larger number of fiber loops surrounding them. All fibers transmit signals in both directions: from the transceiver to a returning point and back. A set of two detectors registers the returning signals, and a time delay between those signals is calculated, which is indicative of the disturbance event location. Polarization states of the returning signals are controlled by transceiver built-in controllers. The event location is determined with different sensitivity in different parts of the monitored structure depending on the density of fibers in these parts.

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 provides a system and a method for testing single-fiber bidirectional optical modules on the basis of an optical fiber circulator. The system and the method are characterized in that the system for testing the single-fiber bidirectional optical modules comprises an error detector, an optical source, a to-be-tested module, a computer, an attenuator, the optical fiber circulator, an optical divider, an oscilloscope and an optical power meter, so that the system for testing transmission parameters and receiving parameters of the module is formed. The system and the method for testing the single-fiber bidirectional optical modules have the advantages that optical fibers are not required to be changed in an integral module testing procedure, transmission indexes of the optical module can be tested, receiving indexes of the optical modules can be measured, adverse factors (such as end surface pollution) caused in a measurement procedure are effectively avoided, accordingly, the stability of test results is guaranteed, and the testing efficiency is improved.

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