165 results about "Vernier effect" patented technology

The invention discloses a photo sensor based on the vernier effect of a broadband light source and a cascading optical waveguide filter, which comprises a broadband light source, an input waveguide, a connecting waveguide, an output waveguide, a reference ring-shaped resonant cavity coupled with the input waveguide and the connecting waveguide, a sensing ring-shaped resonant cavity coupled with the connecting waveguide and the output waveguide and two optical power meters. The sensing ring-shaped resonant cavity and the reference ring-shaped resonant cavity are different in optical length; adjacent resonance peaks are not coincident completely when one resonance frequency of the sensing ring-shaped resonant cavity is coincident with one resonance frequency of the reference ring-shaped resonant cavity. At least a part of waveguides in the sensing ring-shaped resonant cavity are influenced by a measured variable or at least a part of waveguides are in contact with a measured substance; the movement of a resonance line can be caused by measured variable influence or measured substance change; and the vernier effect of double resonant cavities can amplify the movement to be movement of total transmission spectrum envelop and can convert the movement into the change of transmission total output power, thereby detecting the measurement substance simply.

The invention discloses an optical fiber FP (Fabry-Perot) gas pressure sensor with optical vernier effect as well as a preparation method thereof. The sensor comprises single-mode optical fiber, a quartz capillary and photonic crystal optical fiber. The two ends of the quartz capillary are connected one end of the single-mode optical fiber and one end of the photonic crystal optical fiber correspondingly by a fusion welding mode; and the other end of the photonic crystal optical fiber is directly connected with the outside, and the pore structure facilitates the outside gas to enter a cavity of an optical fiber FP sensor, so that the quartz capillary and the photonic crystal optical fiber form two Fabry-Perot resonant cavities with vernier effect. During preparation, a commercial optical fiber fusion splicer is used, the discharging time and the discharging intensity of the electrode are controlled, two types of optical fiber are cascaded, a precise cutting device is used for cutting the optical fiber, and the length of the optical fiber is strictly controlled, so that the vernier effect is generated. The optical fiber FP gas pressure sensor is small in volume, simple and convenient to prepare, high in adaptability and high in sensitivity, and has wide application prospect.

The invention provides a double-microring resonator optical biochemical sensing chip based on the vernier effect and aims to solve the detection problem of some biochemistry matters. The double-microring resonator optical biochemical sensing chip mainly comprises an input straight waveguide, an output straight waveguide and two microring resonators, wherein the first microring resonator comprises an annular waveguide and is coupled with the input straight waveguide and the output straight waveguide; the second microring resonator is positioned on the inner side of the annular waveguide of the first microring resonator and has a free spectral range different from that of the first microring resonator, and the two microring resonators are connected in an optical coupling manner. Through the above scheme adopted by the optical biochemical sensing chip, the second optical resonator is positioned on the inner side of the first optical resonator and connected with the first optical resonator in a lateral coupling manner to form the vernier effect and detect the influence on an optical signal from external substances. Under the condition of meeting the same sensing performance, the size of the optical biochemical sensing chip is greatly reduced, and miniaturization of the optical biochemical sensor and the on-chip sensing system are favorably realized.

The present invention relates to an RF integrated circuit comprising a frequency synthesizer and a QAM modulator for modulating a baseband signal of frequency FBB, the frequency synthesizer supplying to the QAM modulator an output signal of frequency F1 adjustable with a frequency step ΔF1, for forming a carrier signal of the QAM modulator. According to the present invention, the frequency synthesizer is a Vernier effect frequency synthesizer comprising an auxiliary frequency synthesizer supplying an auxiliary signal of frequency F2 adjustable with a frequency step ΔF2 and a main frequency synthesizer having a phase-locked loop bandwidth at least two times higher than the frequency step ΔF2 of the auxiliary signal.

An optical coherence tomography device includes a wavelength scanning laser light source (10) provided with two Fabry-Perot resonators (13A, 13B) provided in a light path for laser oscillation. The values of FSR (free spectral range) of the Fabry-Perot resonators are set so as to be proximate to each other. The resonator length of at least one of the two Fabry-Perot resonators is periodically varied within a preset range to cause the two Fabry-Perot resonators (13A, 13B) to operate as a wavelength length varying filter of a narrow pass band capable of varying the selection wavelength by the vernier effect to output laser light that has wavelength temporally scanned. The optical coherence tomography device also includes an interference optical system (20) that causes the laser light output from the wavelength scanning laser light source (10) to be branched into light for reference and light for observation to be illuminated on an object for observation (60) and that generates interference light of reflected light of the light for observation illuminated on the object for observation (60) and the light for reference. The optical coherence tomography device further includes a signal processing means (50) that receives the interference light obtained from the interference optical system (20) for transforming the received interference light into an electrical signal to calculate the optical tomographic image information of the object for observation (60).

The invention relates to a single mode fiber length measuring system. The single mode fiber length measuring system is characterized in that a pulse light source is connected with a first optical fiber coupler by an optical fiber, an output end of the first optical fiber coupler is connected with a high-speed photoelectric conversion module which is connected with a spectrum analyzer; another output end of the first optical fiber coupler is connected with a passive optical fiber ring cavity consisting of a second optical fiber coupler, a third optical coupler and a single mode optical fiber with the length to be measured, and the passive optical fiber ring cavity is connected with a spectrometer. Compared with the traditional OTDR (Optical Time Domain Reflectometry) measuring method, the optical vernier effect is utilized, so that the measurement resolution is improved greatly. The single mode fiber length measuring system ensures the measuring precision by tracking the measurement drifting caused by unstable intervals between longitudinal modes of the tracking light source of the spectrum analyzer.

The invention provides a vernier effect based dual-micro-ring resonator optical biochemical sensing chip. The chip comprises an SOI (silicon on insulator) substrate consisting of a silicon base layer, a silicon dioxide layer and a mono-crystal layer which are overlapped and bonded from the bottom to the top sequentially; the mono-crystal silicon layer of the SOI substrate comprises two micro-ring resonators which are in optical coupling connection; and the micro-ring resonators are in overlapped shape in the space structure. Because the slit optical waveguide structure is introduced into the scheme and the slit waveguide can be used for limiting light as much as possible in a slit area to intensify the interaction between the light and a substance; the advantages that the light energy density in the slit space is far higher than that in an evanescent field, the interaction between the light and the substance can be stronger, and the detection sensitivity can be higher are achieved. The optical biochemical sensing chip is advantageous to implementation of miniaturization and SOI sensing system of the optical biochemical sensor under the condition of the same sensing performance.

The present invention relates to an RF integrated circuit comprising a frequency synthesizer and a QAM modulator for modulating a baseband signal of frequency FBB, the frequency synthesizer supplying to the QAM modulator an output signal of frequency F1 adjustable with a frequency step ΔF1, for forming a carrier signal of the QAM modulator. According to the present invention, the frequency synthesizer is a Vernier effect frequency synthesizer comprising an auxiliary frequency synthesizer supplying an auxiliary signal of frequency F2 adjustable with a frequency step ΔF2 and a main frequency synthesizer having a phase-locked loop bandwidth at least two times higher than the frequency step ΔF2 of the auxiliary signal.

The invention discloses a digital frequency stability measuring method based on total response time. In a digital environment, quantization error in the digital measurement technology is inhibited by use of a clock vernier effect and a digital edge effect, the phase difference between two signals is measured through a digital phase discrimination algorithm, the frequency stability is obtained according to the phase difference, and thus, frequency stability measurement based on total response time is realized. The method can be used to accurately measure the transient stability, short-term stability and long-term stability of different frequency sources and essentially reveal the change rule of the frequency stability of different frequency sources with response time.

The invention discloses a semiconductor laser. A narrow strip-shaped waveguide is etched on the surface of one side, back to a substrate, of a transmission layer, a first Bragg grating is arranged along one end of the axis of the narrow strip-shaped waveguide, and a second Bragg grating is arranged at the other end of the axis of the narrow-strip-shaped waveguide. The refractive index of a convexpart in the first Bragg grating is smaller than that of a convex part in the second Bragg grating, the refractive index of a concave part in the first Bragg grating is smaller than that of a concave part in the second Bragg grating, and the reflection spectrum of the first Bragg grating and the reflection spectrum of the second Bragg grating overlap at a preset wavelength. The laser outputted by the semiconductor laser can obtain the reflection spectrum superposition similar to a vernier effect, the ultra-narrow reflection spectrum is achieved, the spectral line width of a device is reduced, and the high-power narrow-line-width laser is achieved. The invention also provides a preparation method which also has the above beneficial effects.

The invention relates to a temperature sensor on the basis of interference spectrum vernier effects and loop cavity ring-down spectrum technologies. The temperature sensor sequentially comprises a DFB(distributed feedback) fiber laser device, a polarizer, an electro-optic modulator, an isolator, an FP (Fabry-Perot) cavity, a ring-down loop and a photoelectric detector along the direction of a light path. The ring-down loop sequentially comprises a first coupler, a second coupler, a Sagnac interference ring, a circulator, a ceiling optical grating, an EDFA (erbium doped optical fiber amplifier) and a third coupler along the direction of the light path; continuous light emitted by light sources can be changed into pulsed light after being transmitted through the polarizer and the electro-optic modulator, 10% of the pulsed light is transmitted into the ring-down loop via an input end of the first coupler after the pulsed light is reflected by the FP cavity, 1% of partial energy of the pulsed light is outputted by the third coupler whenever the pulsed light is cycled in the ring-down loop by a circle, and the partial energy can be converted into voltage signals by the photoelectric detector, and the voltage signals can be displayed on an oscilloscope. The temperature sensor on the basis of the interference spectrum vernier effects and the loop cavity ring-down spectrum technologies has the advantage that the sensitivity of the temperature sensor can be improved by dozens of times.

The invention discloses an optical fiber temperature sensing probe and a demodulation method. The optical fiber temperature sensing probe includes a first single-mode optical fiber, a hollow optical fiber, a second single-mode optical fiber, a ceramic ferrule and ultraviolet glue. One end of the hollow optical fiber is fused together with one end of the first single-mode optical fiber and the other end of the hollow optical fiber is fused together with one end of a second single-mode optical fiber, so that a reference Fabry-Perot interferometer. The other end of the second single-mode opticalfiber is inserted into one end of the ceramic ferrule. The ultraviolet glue is filled into the other end of the ceramic ferrule and is in the ceramic ferrule. The end face of the other end of the second single-mode optical fiber is spaced from the end face of the ultraviolet glue, so that a sensing Fabry-Perot interferometer is formed. The reference Fabry-Perot interferometer and the sensing Fabry-Perot interferometer are in cascaded connection so as to form a vernier effect, so that temperature detection flexibility is improved. According to the invention, the optical fiber temperature sensing probe is simple in manufacture method and low in manufacture cost and the temperature detection flexibility is improved.

The invention discloses a light micro-flow biosensor in an inner cavity of a semiconductor laser, which comprises a coupling cavity semiconductor laser, a 2*2 coupler and a phase regulating region arranged on an input port of the coupler. A master mold of the coupling cavity semiconductor laser is output from a coupling output port of the coupler, and a master side mold of the coupling cavity semiconductor laser is output from another coupling output port. The resonant frequency interval of a sensing resonant cavity is 1 / 2 slightly larger than or smaller than that of a reference resonant cavity. A part of the sensing resonant cavity is a sensing region, and the periphery of the sensing region is completely or partially covered by a measured substance. When the refractive index of the measured substance changes, the modes of the coupling cavity semiconductor laser are switched, the phase difference of two resonant cavity output ports has a pi phase jump, the power ratio of two output ports of a detection coupler is changed by a vernier effect, and then, the change of the refractive index of a sample can be measured. The detection limit of the biosensor reaches 10-8 and even lower magnitude.

The invention discloses a spectrum demodulation method and demodulation device based on a vernier effect. The demodulation method includes the steps of measuring a vernier effect spectrum of a cascadestructure, performing fast Fourier transform on the spectrum, an obtained frequency spectrum having three clusters of frequency components, selecting a spatial frequency component with a minimum frequency value, extracting the spatial frequency through a Gaussian filter, and performing fast Fourier transform inversion on the extracted spatial frequency to obtain an envelope of a cascade vernier spectrum. A vernier effect is formed through cascade reference of In-line MZI and the envelope of the vernier spectrum is extracted, and under the same condition, the drift amount of the cascade vernier spectrum envelope is about FSR(R) / (FSR<S>-FSR<R>) times of that of a sensing In-line MZI spectrum, thereby realizing amplification of sensitivity.

The invention relates to an oscilloscope detection temperature sensor based on parallel connection of a Sagnac loop and an FP cavity, which comprises a first coupler, an isolator, a second coupler, anFP cavity, an attenuator, a third coupler a Sagnac loop, a fourth coupler and a flat top grating, and is characterized in that the first coupler is connected with the isolator and a first inlet of the second coupler, one part of a first outlet of the second coupler is connected with an inlet of the FP cavity, the other part of the first outlet of the second coupler is connected with the Sagnac loop through the attenuator and the third coupler, one part of a second inlet of the second coupler is connected with an outlet of the FP cavity, the other part of the second inlet of the second coupleris connected with the attenuator, a second outlet of the second coupler is connected with a first inlet of the fourth coupler, a first inlet of the fourth coupler is connected with an inlet of the flat top grating, an outlet of the flat top grating is connected with a second inlet of the fourth coupler, a second outlet of the fourth coupler is connected with a photoelectric detector and an oscilloscope. The sensitivity of the temperature sensor based on the parallel connection of the Sagnac loop and the FP cavity is improved by dozens of times than that of a temperature sensor based on a single Sagnac loop structure by using a vernier effect.

A semiconductor laser based intra-cavity optical micro-fluidic biosensor comprises a coupled-cavity semiconductor laser, a 2×2 coupler and a phase adjustment section on one input port of the coupler. The dominant mode of the coupled-cavity laser appears in one output port of the coupler, while the adjacent mode comes out from the other output port of the coupler. The resonant frequency interval of the sensing cavity is slightly larger or smaller than one half of that of the reference cavity. Part of the sensing cavity is the sensing section which is covered by an analyte. The refractive index change of the analyte will cause the lasing mode of the coupled cavity to switch to an adjacent mode, resulting in a π-phase change in the phase difference between the two output ports of the two resonance cavities. By applying the Vernier effect, the power ratio of the two output ports of the coupler will change and the refractive index change of the analyte can be derived. A detection limit of 10−8 RIU or smaller can be achieved.

The invention discloses a sensitivity-controllable optical fiber Fabry-Perot air pressure sensor based on the Vernier effect. The sensor comprises a capillary glass tube, incident optical fibers, andreflective optical fibers. The incident optical fibers and the reflective optical fibers are sequentially distributed in the capillary glass tube at intervals. An opening is formed in the side wall ofthe capillary glass tube. The incident optical fibers and the reflective optical fibers are distributed on both sides of the opening. According to the sensitivity-controllable optical fiber Fabry-Perot air pressure sensor based on the Vernier effect, a variety of different sensor sensitivity amplification factors are provided, thereby being suitable for measurement of different pressures, and enlarging the use range of the sensor.

A new reconfigurable cascadable all-optical on-chip device is presented. The gate operates by combining the Vernier effect with a novel effect, the gain-index lever, to help shift the dominant lasing mode from a mode where the laser light is output at one facet to a mode where it is output at the other facet. Since the laser remains above threshold, the speed of the gate for logic operations as well as for reprogramming the function of the gate is primarily limited to the small signal optical modulation speed of the laser, which can be on the order of up to about tens of GHz. The gate can be rapidly and repeatedly reprogrammed to perform any of the basic digital logic operations by using an appropriate analog optical or electrical signal at the gate selection port. Other all-optical functionality includes wavelength conversion, signal duplication, threshold switching, analog to digital conversion, digital to analog conversion, signal routing, and environment sensing. Since each gate can perform different operations, the functionality of such a cascaded circuit grows exponentially.

The invention discloses a hybrid sensor based on a vernier effect of a parallel structure and a manufacturing method of the hybrid sensor. The hybrid sensor comprises a Michelson interferometer and aFabry-Perot interferometer, wherein the Michelson interferometer and the Fabry-Perot interferometer are arranged in parallel. The Michelson interferometer comprises a single-mode optical fiber a, a spherical structure and a special optical fiber PCF which are sequentially arranged in the optical fiber transmission direction. One end of the single-mode optical fiber a is fixedly connected with oneside of the spherical structure, and the other side of the spherical structure is fixedly connected with one end of a special optical fiber PCF; the Fabry-Perot interferometer comprises a single-modeoptical fiber b, a silicon dioxide microtube b and a single-mode optical fiber c which are sequentially arranged in the optical fiber transmission direction, wherein one end of the single-mode opticalfiber b is fixedly connected with one end of the silicon dioxide microtube b, and the other end of the silicon dioxide microtube b is fixedly connected with one end of the single-mode optical fiber c. The sensor has the advantages of simple structure manufacturing, high sensitivity, high stability, low temperature cross sensitivity and the like.

The invention discloses a vernier effect based tunable microfiber laser and a production method thereof. The laser comprises a semiconductor pump laser (1), an active microfiber cascade resonance structure (3) and a spectrum analyzer (5). Pump laser light emitted from the semiconductor pump laser (1) is coupled into the active microfiber cascade resonance structure (3) through a first micro-nanofiber (2), and laser light generated by the active microfiber cascade resonance structure (3) is coupled through a second micro-nanofiber (2) to enter the spectrum analyzer (5). The microfiber laser has tenability, can monitor changes of external environment parameters (such as temperature and refractive index strain), and has the advantages of small size, compact structure, flexible design and the like, thereby being capable of meeting application requirements in different fields of curing material monitoring, environmental pollution monitoring such as gas and soil, biomedical detection and the like.

The invention relates to a high-sensitivity seawater salt temperature two-parameter sensor based on an interference vernier effect. The high-sensitivity seawater salt temperature two-parameter sensor is characterized by comprising a broadband light source, a 2*2 optical fiber coupler, two double-FP-cavity Fabry-Perot interferometers arranged in parallel and a spectrograph, wherein the double-FP-cavity Fabry-Perot interferometer comprises a single-mode optical fiber, an optical fiber microsphere structure with a microfluidic channel and a large-mode-field optical fiber which are arranged in sequence. According to the invention, free spectral ranges of an air cavity and a quartz cavity in the interferometer are close to each other by setting optical fiber microsphere structures with different parameters and large-mode-field optical fiber cavity lengths, a vernier effect is realized, and corresponding frequencies of output spectrums are kept at intervals; when the seawater salt temperature changes, the cavity length of the interferometer changes, Fourier transform and filtering are carried out on output spectrums, and the output spectrums and envelopes of all the interferometers are obtained; the simultaneous measurement of two parameters can be realized through the envelope signal drift distance in combination with the salinity and temperature sensitivity matrix; and the high-sensitivity seawater salt temperature two-parameter sensor has the advantages of high practicability, compact structure, high sensitivity, high stability, capability of simultaneously measuring multiple parameters and the like.

An optical transmitter includes a reflective semiconductor optical amplifier (RSOA) coupled to an input end of a first optical waveguide. An end of the first optical waveguide provides a transmitter output for the optical transmitter. Moreover, a section of the first optical waveguide between the input end and the output end is optically coupled to a ring modulator that modulates an optical signal based on an electrical input signal. A passive ring filter (or a 1×N silicon-photonic switch and a bank of band reflectors) is connected to provide a mirror that reflects light received from the second optical waveguide back toward the RSOA to form a lasing cavity. Moreover, the ring modulator and the passive ring filter have different sizes, which causes a Vernier effect that provides a large wavelength tuning range for the lasing cavity in response to tuning the ring modulator and the passive ring filter.

The invention discloses a sensitivity enhanced sensor based on a Loyt-Sagnac interferometer. The sensor is characterized in that a laser beam emitted by a broadband light source is input to a coupler 3 via an optical isolator 2, the coupler divides light waves into two paths transmitted in different directions, the light transmitted in the clockwise direction passes a first polarization controller 4, a reference fiber 5, a single-mode fiber 6, a second polarization controller 7 and a sensing fiber 8 in a loop, the light transmitted in the anticlockwise direction passes the sensing fiber 8, the second polarization controller 7, the single-mode fiber, the reference fiber and the first polarization controller 4, the length difference between the reference fiber and the sensing fiber is 10%, the two light beams pass the loop again, reach the coupler 3 and output coherently, and output light is received by a spectrum analyzer 9 for subsequent analysis. A new interferometer structure uses two high-birefringence fibers (the reference fiber 5 and the sensing fiber 8) of different lengths to generate a vernier effect, the measuring precision can be effectively improved, the structure is simple, preparation is easy, the cost is low, and the sensitivity enhanced sensor has potential in high-precision physical quantity sensing.

The invention discloses an optical biochemical sensor based on a spiral runway type interference structure. The optical biochemical sensor comprises an input straight waveguide, a first right semicircle waveguide, a first straight waveguide, a first left semicircle waveguide, a second straight waveguide, a second right semicircle waveguide, a third straight waveguide, a second left semicircle waveguide, and an output straight waveguide, wherein the input straight waveguide, the first straight waveguide, the second straight waveguide, the third straight waveguide and the output straight waveguide are all mutually parallel to one another. According to the invention, a double-running way type resonant cavity formed by one spiral waveguide structure is adopted, so that transmission pectra of two running ways are overlapped due to the vernier effect, and a harmonic peak with a wide free spectral region and high sensitivity is obtained; through measuring the shift of the harmonic peak with the high sensibility, the variations of the modal effective refractive indexes inside the waveguides can be obtained, and further information about the refractive indexes and the concentration of an object tested is obtained.

The invention provides a cascade capillary optical fiber baroceptor based on vernier effect and a preparation method, the cascade capillary optical fiber baroceptor comprises a single-mode optical fiber, a large-inner-diameter (hollow) capillary optical fiber and a small-inner-diameter (hollow) capillary optical fiber, two ends of the large-inner-diameter capillary optical fiber are respectively connected with the single-mode optical fiber and the small-inner-diameter capillary optical fiber; the large-inner-diameter capillary optical fiber and the small-inner-diameter capillary optical fiberform two cascaded FP cavities with vernier effects, and the single-mode optical fiber is an input optical fiber. The sensor is simple to manufacture, low in cost and high in sensitivity in a low-voltage range.

The invention discloses a stress sensing device based on a hybrid cascaded optical fiber interferometer, and a demodulation method. The stress sensing device comprises a broadband light source, a Sagnac interferometer, an optical fiber mode interferometer, and a signal processing unit which are connected in order; the optical fiber mode interferometer is composed of an incident single-mode opticalfiber, a few-mode optical fiber, and an emitting single-mode optical fiber; the Sagnac interferometer is used as a reference interferometer, the optical fiber model interferometer is used as a sensing interferometer, and the optical Vernier effect is realized by cascading the Sagnac interferometer and the optical fiber model interferometer; the envelope numerical value change of the hybrid cascaded optical fiber interferometer is observed through the signal processing unit, thereby realizing the sensing demodulation. The influence on the sensor by the tiny airflow and micro-vibration and likeexternal perturbation can be avoided by utilizing the polarization unsensitive characteristic of the few-mode optical fiber; the sensing demodulation is realized by observing the envelope numerical value change of the hybrid cascaded optical fiber interferometer by utilizing the optical Vernier effect. And the sensing device has the features of being simple in preparation, low in cost and high insensitivity.

The invention provides a temperature-insensitive magnetic field sensor based on a magnetic fluid filling optical fiber microcavity. The magnetic field sensor comprises a sensing head, an optical fiber coupler, a spectrograph and a wide-spectrum optical source. The sensing head is formed by an air chamber and a magnetic liquid cavity which are cascaded. An absolute value of a difference between free spectrum scopes of the air chamber and the magnetic liquid cavity is less than 1 / 10 of the magnetic liquid cavity. Wide spectrum light emitted by the wide-spectrum optical source enters into the sensing head via the optical fiber coupler. An optical signal reflected by the air chamber and the magnetic liquid cavity enters into the spectrograph via the optical fiber coupler. An optical signal reflected by the air chamber and the magnetic liquid cavity generates a vernier effect so that measured sensitivity of a magnetic field is greatly increased. An optical fiber support structure designed in the invention is fixed to a single-mode fiber and a panda fiber of two sides of the magnetic liquid cavity, and a thermal expansion effect of an optical fiber support is used to offset a thermo-optic effect of a magnetic fluid so that automatic compensation of a temperature is realized. The magnetic field sensor possesses advantages that the temperature can be automatically compensated; the structure is compact; sensitivity is high; and a measured range is large.

The present invention relates to a strain sensing Fabry-Perot interferometer, comprising a first single mode fiber, a second single mode fiber and a capillary microtube, wherein the capillary microtube is fused between the first single mode fiber and the second single mode fiber. The strain sensing Fabry-Perot interferometer proposed by the invention has the advantages of simple structure, convenient manufacturing and easy design of various cavity shapes. A strain sensing method based on the strain sensing Fabry-Perot interferometer is used for achieving a vernier effect by connecting two single-cavity fiber Fabry-Perot interferometers in parallel by using a fiber coupler, so that the sensitivity of strain sensing is improved.

The invention discloses a fiber optic sensor based on an edge-hole fiber double Mach zehnder interference vernier effect. The fiber optic sensor comprises a broadband light source, a first single-modefiber, a first coreless fiber, a side-hole fiber with at least two air holes and exposed partial holes, a second coreless fiber, a second single-mode fiber, and a spectrometer; energy of a optical field is divided and enters a fiber core of the side-hole fiber, a hole connected with the external environment and a closed hole by the first coreless fiber; the three optical field energies are combined by the second coreless fiber and then output to the spectrometer by the second single-mode fiber; interference occurs between two beams of light from the fiber core of the side-hole fiber and the hole connected with the external environment, Mach zehnder interference is formed, and interference spectrum varies with the external environment; the Mach zehnder interference also occurs in the two beams of light from the fiber core and the enclosed hole, and an interference spectrum is not affected by change of the external environment; and the two Mach zehnder interferences are in parallel to form the vernier effect, and thus the sensor has 44084.1 nm / RIU ultra-high sensitivity.

The invention puts forward an interferometer cascaded by two Fabry-Perot cavities on the basis of an optical fiber line. The interferometer comprises a broadband light source, a circulator, a sensinghead and a spectrum analyzer, wherein the sensing head is manufactured by a single-mode optical fiber or a multimode optical fiber. The interferometer is characterized in that femtosecond laser is used for inscribing four reflecting mirror surfaces which vertically penetrate through a fiber core and have the same size, wherein the end surface of the optical fiber is cut into a wedge shape to eliminate end surface reflection interference, and all reflecting mirrors and the optical fiber form the sensing head of the Fabry-Perot cavity interferometer. Light from the broadband light source is received by the circulator and is transmitted to the sensing head, then, the sensing head returns the light to the circulator, and the light is transmitted to the spectrum analyzer through the circulatorso as to form the cascade Fabry-Perot cavity interferometer. The interferometer has the characteristics of being simple in structure, simple in manufacture, low in cost, high in sensitivity and the like.