26 results about "Cladding mode" patented technology

The invention, which relates to the technical field of the hollow-core optical fiber, provides a hollow-core optical fiber with an anti-resonance layer having a multi-layer opening structure, comprising an outer cladding sleeve, an anti-resonance area and a hollow-core fiber core area enclosed by the anti-resonance area. The anti-resonance area comprises a plurality of anti-resonance units, each anti-resonance unit comprises at least one anti-resonance layer of an opening structure, and the edges of the two sides of an opening of each anti-resonance layer are connected with the inner wall of the outer cladding sleeve through two parallel thin walls. The optical fiber has the beneficial effects that multiple anti-resonance effects are generated through the opening anti-resonance layer, so that a light field is prevented from leaking to the cladding from the fiber core, and the light field is effectively limited in the hollow fiber core area for transmission; each anti-resonance layer is indirectly connected with the inner wall of the outer sleeve through a parallel thin wall, so that a connection node is far away from the fiber core, node coupling is reduced, and leakage of a light field to the cladding is weakened. The anti-resonance layer and the sleeve form a closed cavity, so that a high-refractive-index area is compared with a low-refractive-index medium in the cavity, a specific wavelength is reflected, a light field is prevented from being coupled with a cladding mode, and the light limiting capability is enhanced.

This invention relates to the field of LC connector testing technology and discloses a B-value testing device for LC fiber optic connectors. This invention solves the problem that existing LC connector B-value testing using mechanized equipment does not consider the influence of the fiber cladding mode on the test data. The invention utilizes an electric push rod, a first push plate, a second push plate, and a compression spring. Activating the electric push rod causes the upper clamping block to move upwards and outwards. This raises one end of the output and input fibers connected to the upper clamping block to a certain height, then pulls one end towards the other. Since the lower clamping block remains stationary, the movement of the upper clamping block causes the output and input fibers to be squeezed into a loop. Due to the special shape of this loop, a signal attenuation effect is generated, thereby eliminating the additional optical signal brought by the cladding mode and avoiding deviations in the test values. Furthermore, the looping is controlled mechanically, making it easier to control the loop diameter compared to manual looping, preventing excessively large loop diameters and excessive losses.

The invention belongs to the field of optical fiber sensing, and particularly relates to a material and structure combined sensitization optical fiber SPR (surface plasmon resonance) sensor and a manufacturing and using method thereof, the sensor comprises a cladding mode attenuation area, a fiber core angle regulation and control area, an SPR sensing area and a thick core light receiving area which are connected in sequence; the cladding mode attenuation area is a six-core optical fiber of which the surface is provided with a coating layer; the fiber core angle regulation and control region is a torsion type six-core optical fiber; a gold film, an MOF-808 material and a medicine component are sequentially arranged on the surface of the SPR sensing area. Cladding mode light is attenuated to zero under the absorption of the cladding and the high-refractive-index coating layer, SPR incident angles when light beams in the six fiber cores are incident to a gold film in an SPR sensing area are adjusted, and then the intensity of an electric field is enhanced through MOF-808, so that the sensitivity of the sensor is improved; when the drug component is combined with the target spot, the SPR resonance valley moves to realize drug-target spot affinity detection; the invention solves the problem of low sensitivity of the traditional optical fiber SPR sensor, and has the advantage of high mechanical strength.

The application discloses a method for suppressing stimulated Brillouin scattering effect by using a cascaded long-period fiber grating. The transmission spectrum of the cascaded long-period fiber grating has a series of comb-shaped resonance peaks, two adjacent resonance peaks are regarded as a passband and two stopbands, the passband bandwidth and resonance wavelength are changed by adjusting the parameters of the cascaded long-period fiber grating, the passband and stopband formed by the adjacent resonance peaks of the transmission spectrum correspond to signal light and Stokes light generated by the stimulated Brillouin scattering effect respectively, so that the non-working side lobe laser is coupled from the core mode to the cladding mode while the signal light passes through. The performance stability of the cascaded long-period fiber grating is improved by using a water ring flow-based desensitization packaging technology, so that the output power level and beam quality of the fiber laser are improved, and the possibility of laser damage is reduced. The application has the characteristics of low cost, high flexibility and strong applicability.

The invention discloses a laser cleaning and cladding cooperative control method and device based on an unmanned aerial vehicle, electronic equipment, a readable storage medium and a computer program product. The method comprises the following steps: determining an operation target; when the surface corrosion depth of the operation target exceeds a preset depth threshold value, the current operation mode of the unmanned aerial vehicle is adjusted to be a cleaning mode; performing laser cleaning operation on the operation target in the cleaning mode; when it is detected that the target metal ion characteristic peak intensity on the surface of the operation target reaches a preset intensity threshold value, the current operation mode of the unmanned aerial vehicle is switched from a cleaning mode to a cladding mode; and performing cladding operation on the operation target in the cladding mode. According to the method, the problems that in the prior art, due to step-by-step cleaning and cladding operation, the exposure time of the metal surface is too long, secondary oxidation is prone to occurring, and the bonding quality and the operation efficiency of a cladding layer are affected can be solved.

The utility model discloses a double-parameter optical fiber sensor based on a conical few-mode fiber grating, which belongs to the technical field of optical fiber sensors and comprises a broadband light source (1), a sensing structure (2) and a spectrum analyzer (3). The sensing structure (2) comprises a first single-mode fiber (201), a coreless fiber (202), a conical few-mode fiber grating (203) and a second single-mode fiber (204); more cladding modes are generated through mode field mismatch of the single-mode optical fiber and the coreless optical fiber and bending of a conical area, the double-parameter sensitivity of the sensor is improved, and two transmission characteristic peaks appear on the fiber bragg grating inscribed on the few-mode optical fiber by using different mode numbers in the few-mode optical fiber. The reliability and repeatability of the sensor are greatly improved, the corresponding double-parameter sensitivity can be respectively calculated by observing the position change of an interference spectrum and a transmission characteristic peak, and a sensitivity matrix is further established, so that the simultaneous measurement of double parameters is realized. The sensor has the characteristics of high sensitivity, strong reliability, strong anti-interference capability, small size, simplicity in manufacturing and the like.

The invention provides a fiber core alignment welding device of a soft glass active optical fiber, which comprises a first monitoring light source, a second monitoring light source, a wavelength division multiplexer, an optical fiber to be welded, a cladding mode stripper, the soft glass active optical fiber, an optical fiber welding machine, a dichroscope, a light spot analyzer and a power meter, the wavelength of the output first monitoring laser is located in an absorption band of the soft glass active optical fiber; a tail fiber of the second monitoring light source is a single-mode optical fiber, the wavelength for outputting the second monitoring laser is located outside the absorption band of the soft glass active optical fiber, and a fiber core of the soft glass active optical fiber is a single-mode waveguide for the second monitoring laser; the dichroscope is used for splitting the first monitoring laser and the second monitoring laser output by the soft glass active optical fiber; and the power meter is used for measuring the power of the first monitoring laser. The invention further provides a fiber core alignment welding parameter optimization method of the soft glass active optical fiber.

The invention belongs to the field of optical fiber interference sensors, and particularly relates to an optical fiber Mach-Zehnder interferometer strain sensor based on a bending structure and a manufacturing and using method of the optical fiber Mach-Zehnder interferometer strain sensor. Comprising a light injection area, a bent optical fiber sensing area and a light receiving area which are sequentially arranged on an optical fiber; the bent optical fiber sensing area is divided into an oxyhydrogen flame heating spiral wave structure and a capillary copper pipe wrapped spring structure; a cladding mode field of the bent optical fiber sensing area deflects to the outer side of the bent structure, and under the action of strain, the strain is concentrated on the inner side of the bent optical fiber sensing area; a cladding mode field offset area and a strain concentration area of the bent optical fiber sensing area are separated in space, the reduction amount of effective refractive index of a cladding mode in the strain process is reduced, and high-sensitivity MZI strain sensing is achieved; the problem that an existing MZI strain sensor is low in sensitivity is solved.

The application provides a kind of optical fiber polarizer based on hollow negative curvature optical fiber, which comprises: a base layer with a hollow structure inside; a core layer arranged at the center of the base layer; an asymmetric cladding structure arranged between the base layer and the core layer, comprising: a pair of first capsule nesting units arranged in the y direction of the core layer, and six second capsule nesting units uniformly distributed in non-y direction.According to the application, the two schemes of air area in the asymmetrically distributed different tube thickness and expanded y direction cladding are combined, which effectively enhances y the coupling of polarization state and cladding mode, realizes excellent single-mode single-polarization performance; effectively increases the confinement loss of y polarization base mode, and further realizes high enough polarization extinction ratio in a larger bandwidth range, and has good bending and spiral resistance.

The invention discloses a linear polarization narrow linewidth fiber laser based on fast and slow axis orthogonal gratings, which comprises two polarization-maintaining cladding mode stripping devices, a polarization-maintaining pumping beam combiner, an output head, a polarization-maintaining gain fiber, a polarization-maintaining high-reflectivity grating and a polarization-maintaining low-reflectivity grating, wherein the etching grating surfaces of the polarization-maintaining high-reflectivity grating and the polarization-maintaining low-reflectivity grating are vertically orthogonal; each of the polarization-maintaining high-reflectivity grating and the polarization-maintaining low-reflectivity grating comprises a polarization-maintaining optical fiber and a grating body, the polarization-maintaining optical fiber comprises two stress rods, a fiber core and a cladding, the fiber core is located between the two stress rods, the cladding is used for wrapping the stress rods and the fiber core, and the grating body is arranged in the fiber core. In the invention, due to the application of the orthogonal grating and optical fiber vertical welding mode, the polarization mode of vertical welding is suppressed due to large loss and loss of advantages in competition, otherwise, the laser signal in the other polarization direction obtains advantages in competition and is continuously subjected to gain amplification, so that the laser signal obtains a relatively high linear polarization degree, and the polarization extinction ratio is improved.

The invention provides an optical fiber polarizer based on a hollow-core negative-curvature optical fiber, and the optical fiber polarizer based on the hollow-core negative-curvature optical fiber comprises a base layer which is of a hollow structure; the fiber core layer is arranged at the center in the base layer; the asymmetric cladding structure is arranged between the base layer and the fiber core layer, and the asymmetric cladding structure comprises a pair of first capsule nesting units arranged in the y direction of the fiber core layer and six second capsule nesting units uniformly distributed in the non-y direction. According to the invention, by combining two schemes of asymmetrically distributing different tube thicknesses and expanding an air area of the cladding in the y direction, coupling of a y polarization state and a cladding mode is effectively enhanced, and excellent single-mode single-polarization performance is realized; the limiting loss of a y polarization fundamental mode is effectively increased, the polarization extinction ratio is high enough in a large bandwidth range, and good bending resistance and spiral resistance are achieved.

An optical fiber device has a fiber core, a cladding layer around the fiber core and a plurality of tilted fiber Bragg gratings, FBGs, in the fiber core at a sequence of positions along the optical axis of the fiber core. The tilted FBGs are configured to reflect and transmit respective non zero fractions of the optical power of light with a predetermined optical reflection wavelength defined by the tilted FBG from the fiber core at the position of the tilted FBG. The tilted FBGs having a tilt angle in an angle range wherein the tilted FBG reflects light from the fiber core perpendicularly to the fiber core or with a deviation from perpendicular reflection at which the reflected light does not give rise to cladding mode generation at the predetermined optical reflection wavelength of the tilted FBG. Photo-acoustic conversion material is provided on the cladding layer at least in areas where light reflected by the tilted FBGs at said positions emerges from the cladding layer, the cladding layer extending continuously at said areas.

The invention relates to a method for testing a fiber core absorption coefficient of a high-doping-concentration double-cladding erbium-doped optical fiber, and belongs to the technical field of optical fiber lasers. And performing end face processing on two ends of the first matching passive optical fiber, the double-cladding erbium-doped optical fiber to be measured and the second matching passive optical fiber. One end of the first matching passive optical fiber is connected with the light source output end, and an input cladding light filtering module is arranged on the first matching passive optical fiber; one end of the second matching passive optical fiber is connected with the input end of the optical signal receiving device, and the second matching passive optical fiber is provided with an output cladding light filtering module; the other end of the first matching passive optical fiber is welded with one end of a to-be-tested double-cladding erbium-doped optical fiber to form a first welding point; the other end of the to-be-tested double-cladding erbium-doped fiber is welded with the other end of the second matching passive fiber to form a second welding point; and respectively carrying out measurement and data processing on the transmission light power of the to-be-measured double-cladding erbium-doped optical fibers with the lengths of L1 and L2. According to the invention, effective separation of fiber core signals and cladding light is realized, interference of a cladding mode on fiber core transmission light is eliminated, and the test accuracy is improved.

The invention discloses a flexible sliding tactile sensor based on a TFBG (Tilted Fiber Bragg Grating) and a preparation method thereof. The sensor is of a sandwich structure formed by an upper parallel stripe ridge packaging layer, a first supporting optical fiber, the TFBG, a second supporting optical fiber and a lower packaging layer. The first supporting optical fiber and the second supporting optical fiber are located on the left side face and the right side face of the TFBG respectively. The directly applied weak positive pressure causes the flexible packaging layer to deform, and gradually wraps the TFBG, thereby increasing the contact angle between the surface of the optical fiber cladding and the packaging layer, and causing the loss of the cladding mode. Along with the change of the contact surface of the packaging layer and the TFBG, the intensity of the cladding mode changes, and by analyzing the transmission spectrum of the TFBG, the pressure and slippage can be measured directly through the change of the intensity of the transmission spectrum. The sensor has the advantages of being simple in structure, high in sensitivity and resistant to electromagnetic interference.

Efficient acousto-optic switching of light between two cores of a multicore optical fiber can be achieved using fiber configurations with cores differing in their effective refractive indices, by simultaneously exciting two flexural acoustic waves of different frequencies to transfer the light in a two-step process from one core to an intermediate cladding mode and then from the intermediate cladding mode to the other core. The intermediate cladding mode may be selected to achieve high, similar coupling rates between the two cores and the cladding modes, and sufficient acoustic frequency separation from neighboring cladding modes.

The invention discloses a preparation method of a phase mask plate with nonlinear + / -1-order diffraction efficiency and period distribution. For dispersion fiber grating reflection spectrum flatness degradation caused by dual effects of cladding mode coupling and the Fabry-Perot effect, gate region refractive index modulation depth distribution curve optimization is carried out, and design parameters of phase mask plate nonlinear + / -1 level diffraction efficiency and groove depth distribution are obtained; according to the requirement for femtosecond laser system multi-order dispersion registration, improvement of phase mask plate groove width distribution design parameters is carried out according to the mapping relation between a multi-order dispersion value and a non-linear period, and finally the phase mask plate preparation method with + / -1-order diffraction efficiency and period distribution optimization is obtained. The method provides an effective means for preparation of the dispersion fiber grating which is highly flat in reflection spectrum and can be registered with multi-order dispersion of a femtosecond laser system, and compared with the prior art, the method provided by the invention has the advantages of low cost, high flexibility, high stability and the like.

This invention discloses a fiber optic sensor and detection system for detecting protamine sulfate. The sensor comprises a fiber optic interference structure and a functionalized thin film of chitosan and heparin self-assembled layer by layer. The fiber optic interference structure uses a cascade of single-mode fiber-coreless fiber-single-mode fiber, generating mode interference and exciting the evanescent field of the cladding mode at the coreless fiber to form a fiber optic sensing structure. Chitosan and heparin are self-assembled into a molecular film through layer-by-layer stacking based on the principle of electrostatic adsorption. The target biological protein molecule is fixed to the surface of the molecular film by the specific binding of heparin to the target protein molecule in the molecular film. This invention utilizes the sensitivity of the evanescent field of the fiber optic interference structure to the refractive index of the environment. The specific binding of the target protein to the surface molecular film amplifies the specific binding signal, which not only greatly improves the detection sensitivity and detection limit, but also is simple and easy to implement, with excellent detection repeatability.

The disclosure provides a waveguide integrated superconducting single photon detector, which can be applied to the technical field of photoelectric detection, and the detector comprises a substrate, a lower cladding layer, a mode spot converter, a waveguide detector and an upper cladding layer; the lower cladding layer is located on the upper surface of the substrate; the mode spot converter and the waveguide detector are located between the lower cladding layer and the upper cladding layer; the mode spot converter comprises two symmetric narrow-end staggered taper mode spot converters; the waveguide detector comprises a waveguide core layer, a photon absorption layer and an electrode layer; the photon absorption layer is located on the upper surface of the waveguide core layer and is connected with the electrode layer; and the wide end of one of the taper mode spot converters is connected with the waveguide core layer. The detector provided by the disclosure has the advantages of realizing polarization independence and anti-stray light interference. The disclosure further provides a waveguide integrated superconducting single photon detector preparation method and a test device.

The invention discloses a long-period fiber bragg grating barometric sensor based on mode conversion and temperature compensation. The long-period fiber bragg grating barometric sensor comprises a long-period fiber bragg grating, the PVA coating is coated on the outer surface of the long-period fiber grating, and the thickness of the PVA coating is configured to enable the effective refractive index of a cladding mode to be in a mode conversion interval; the outer surface of the PVA coating is coated with the PDMS coating, and the PDMS coating is configured to respond to external air pressure change and change the refractive index of the PDMS coating; and the fiber bragg grating and the long-period fiber bragg grating are connected in series in the same optical fiber light path, and the fiber bragg grating is used for sensing the environment temperature and performing temperature compensation on the air pressure measurement result of the long-period fiber bragg grating. The outer surface of the long-period fiber grating is coated with the PVA coating, the outer surface of the PVA coating is coated with the PDMS coating, and the fiber bragg grating is connected in series, so that the cross sensitivity influence of temperature change on an air pressure measurement structure is effectively solved, and the measurement precision and reliability of the sensor are remarkably improved.

The invention relates to an optical fiber vibration sensor based on femtosecond processing and a measurement method. The optical fiber vibration sensor comprises a first fiber core, a cladding film and a composite beam, one end of the composite beam is connected with one end of the cladding mold, the cladding mold wraps the outer surface of the first fiber core, the end, facing the composite beam, of the first fiber core is exposed outside, the end, facing the composite beam, of the first fiber core is a first reflection point, and the inner side wall, facing the first fiber core, of the composite beam is a second reflection point. A cavity between the first reflection point and the second reflection point forms an interference cavity; through the arrangement of the composite beam, the interior of the optical fiber vibration sensor is not provided with resin or glue and other materials which are liable to age, all the materials are optical fiber glass materials, and all the devices are in an unstressed or low-stress state. The problems of glue aging, fatigue deformation and null drift of the vibration sensor based on the fiber bragg grating and the distributed optical fiber in long-term use can be effectively solved; in addition, through the arrangement of the interference cavity, the measurement precision of vibration is improved.

The invention provides a battery in-situ fiber bragg grating sensor monitoring system and method, the system comprises a broadband light source, a spectrometer, a circulator and a fiber bragg grating sensor, and the broadband light source and the spectrometer are connected with the fiber bragg grating sensor through the circulator. The fiber grating sensor is implanted into the battery; the battery is connected with the charging and discharging device. The broadband light source transmits a light source signal to the sensor through the circulator, so that the sensor converts fiber core mode light into cladding mode light, and a cladding mode leakage mode is generated; the spectrograph collects a spectral signal output by the sensor through the circulator, analyzes a leakage mode envelope area variation corresponding to a cladding mode leakage mode, and realizes in-situ monitoring of the wetting condition of the electrolyte in the battery. According to the invention, the fiber grating sensor capable of generating a cladding mode leakage mode is implanted into the battery and clings to an electrode or a diaphragm, and the requirements of battery aging early warning, service life prolonging, charging and discharging optimization and secondary utilization can be met by analyzing the change quantity of the leakage mode envelope area.

The invention provides a two-parameter measurement optical fiber sensor based on a conical structure and a manufacturing method of the two-parameter measurement optical fiber sensor. The sensor is formed by sequentially connecting a single-mode optical fiber, a first photonic crystal optical fiber (PCF-1), a suspended photonic crystal optical fiber (PM-PCF) and a second photonic crystal optical fiber (PCF-2), and a first conical melting structure and a second conical melting structure are formed at the joints of PCF-1 / PM-PCF and PM-PCF / PCF-2 respectively, the former is used for exciting a fiber core fundamental mode part into a cladding mode, and the latter realizes recoupling and outputs an interference spectrum; the change of the effective refractive index difference of the mode is caused by the change of the external refractive index and the temperature, the transmission spectrum line displacement is shown, the sensitivity matrix is calibrated by adopting at least two spectral line characteristics, the decoupling reconstruction of the refractive index and the temperature is realized, and the structure is compact in size, low in insertion loss, small in temperature crosstalk sensitivity, controllable in process parameter and good in repeatability. The method is suitable for batch preparation.

The invention provides film surface defect detection equipment which comprises a rack, a to-be-detected piece sequentially passes through the top ends of transmission rollers, and the to-be-detected piece passing through the area between the two transmission rollers is arranged in the horizontal direction; comprising a guide unit and a plurality of lighting units, the guide unit is arranged on the outer side of a to-be-detected piece walking between two transmission rollers and arranged in a wrapping mode along the outer contour of the to-be-detected piece, and an imaging assembly is arranged on one side of the follow-up lighting assembly. The illumination unit synchronously moves along with the to-be-detected piece along the track of the guide unit, and the illumination unit sequentially completes switching from oblique light to positive light in a local area, so that the imaging assembly obtains illumination information of different incident angles in continuous images. The oblique light enhances the shadow contrast of the surface micro-protrusions or micro-grooves, and the positive light highlights the texture uniformity and color difference. The combination of the two can significantly improve the visualization effect of directional defects such as fine scratches and the like, thereby improving the accuracy and reliability of scratch defect identification.

This invention discloses a device, method, and testing method for preparing cladding mode stripping samples of double-clad optical fibers. The device features a groove bent along a smooth path. The sample preparation method includes the following steps: taking a double-clad optical fiber to be tested; using a predetermined length of the beginning of the double-clad fiber as a cladding mode stripping segment; and bending the cladding mode stripping segment along a predetermined smooth path to form a pre-fabricated test sample. The testing method includes the following steps: preparation of the cladding mode stripped sample; and light injection testing. This invention cleanly strips the cladding mode from the test sample prepared from the optical fiber to be tested, rather than from the testing device end. Thus, while ensuring the accuracy of the test results, cladding mode stripping and light injection testing are separated into two completely independent steps, executed simultaneously in parallel. This makes the test results more accurate and unaffected by the cladding mode, while also improving the test efficiency.

The invention relates to a multimode hollow-core anti-resonance optical fiber. The cladding region comprises an outer cladding, a circular cladding tube, a semi-elliptical cladding tube and an anti-resonance plate; a plurality of circular cladding tubes each attached to the inner surface of the outer cladding; the plurality of circular cladding tubes are arranged along the circumferential direction of the inner surface of the outer cladding, the plurality of circular cladding tubes are uniformly and circumferentially distributed at equal intervals, and the inner surface of the outer cladding except a cladding area is a fiber core area; a semi-elliptical cladding tube is arranged on the outer side of each circular cladding tube, and an anti-resonance plate is arranged in each circular cladding tube; the connecting straight line of the midpoint of the section of the anti-resonance plate and the center of the outer cladding passes through the circle center of the circular cladding tube, the anti-resonance plate coincides with the short axis of the semi-elliptical cladding tube, the diameter of the anti-resonance plate coincides with the diameter of the circular cladding tube, and the short axis of the semi-elliptical cladding tube coincides with the diameter of the circular cladding tube. On the basis of the structure, the invention further provides several alternative schemes, coupling of a high-order mode and a cladding mode of the fiber core can also be avoided, and multimode transmission is achieved.