397 results about "Multimode fibre" patented technology

The invention discloses a micro-nano fiber grating laser writing method and a micro-nano fiber grating laser writing device. The method comprises the following steps of: tapering normal multi-mode fibers; manufacturing micro-nano fibers; and then taking 193 nm ultraviolet laser as a scribing means. The device comprises a fiber clamp, and an ArF excimer laser, a 45-degree full power reflector, a cylindrical lens and a phase mask plate which are sequentially arranged, wherein the ArF excimer laser is used for emitting 193 nm ultraviolet laser; the tapered fiber is fixed on the fiber clamp; micro-nano fiber regions of the fibers are arranged in front of the phase mask plate in parallel; the 193 nm ultraviolet laser emitted by the ArF excimer laser is reflected through the 45-degree full power reflector and then vertically emitted to the cylindrical lens; and the phase mask plate is arranged in front of the cylindrical lens. According to the method and the device, extra processing for the fibers is not required, the mechanical strength and the toughness of the fibers are kept, the cost is low, the scribing efficiency is high, the bandwidth is narrow, the mode is controllable and the repeatability is high.

The invention provides an inner wall-silver plated and liquid crystal-filled hollow optical fiber surface plasmon resonance temperature sensor and belongs to the optical fiber sensing technical field. According to the structure of the sensor, the interior of a hollow glass optical fiber is plated with silver, and the silver-plated hollow glass optical fiber is filled with liquid crystal; the inner diameter of the hollow glass optical fiber ranges from 300 microns to 500 microns, the numerical aperture of the hollow glass optical fiber is not lower than 0.27, and the length of the hollow glass optical fiber ranges from 30 mm to 50 mm; sensitization treatment is performed on the inner wall of the hollow glass optical fiber, and a 45nm-to 80nm uniform silver film is formed in the optical fiber through adopting a liquid phase chemical deposition method, and therefore, a sensing layer of surface plasmon resonance can be formed; and the hollow optical fiber is filled with thermotropic nematic liquid crystal, and plastic-clad multimode optical fibers are coupled to the ports of the optical fiber respectively, and end sealing processing is realized. With the inner wall-silver plated and liquid crystal-filled hollow optical fiber surface plasmon resonance temperature sensor adopted, subtle temperature changes can be dynamically monitored in real time. The inner wall-silver plated and liquid crystal-filled hollow optical fiber surface plasmon resonance temperature sensor is suitable for long-distance transmission. According to the inner wall-silver plated and liquid crystal-filled hollow optical fiber surface plasmon resonance temperature sensor, special inner wall silver plating technology is adopted, and the hollow optical fiber is filled with the thermotropic liquid crystal, and therefore, the oxidation of the external silver layer of the solid optical fiber surface plasma resonance sensor can be avoided.

A method for imaging an object with resolution that exceeds the number of spatial modes per polarization in a multimode fiber is disclosed. In some embodiments, the object is interrogated with a plurality of non-spot-sized intensity patterns and the optical power reflected by the object is detected for each intensity pattern. The plurality of optical power values is then used in a non-local reconstruction based on an optimization approach to reconstruct an image of the object, where the image has resolution up to four times greater than provided by prior-art multimode fiber-based imaging methods.

A lamellar grating interferometer is described, in which the light beams are collimated and focused onto the grating by means of mirror 9, which at the same time serves for collecting the light reflected from the grating. In this case, the light beam of a white light source 1 is first collimated by means of first lens 2, and subsequently passed through a sample cuvette 3. The transmitted light beam is subsequentlyy focused and coupled by another lens 2 into a fibre 17. The light to this fibre 17 is subsequentlyy directed towards a mirror 9, reflected from this mirror 9 onto a grating 11, which forms part of a lamellar grating interferometer which is realised by means of a micro electro mechanical device MEMS 7, which is mounted on a MEMS holder 6, as is the fibre 17. The light reflected from this grating 11 is reflected onto the same mirror 9, and focused and coupled by this same mirror 9 into a second multimode fibre 18, which is also fastened to the holder 6. The light guided by this second multimode fibre 18 is subsequently fed into a detection device 4.

The invention discloses an optical transmitting antenna system and a beam control method thereof. An optical antenna has an array structure which is formed by uniformly arranging a plurality of laser transmitting antennae and a plurality of receiving antennae. The array structure is arranged on a cambered surface (a hemispherical surface or a spherical surface). Each laser transmitting antenna comprises a transmitting multimode fiber and a transmitting micro-lens. Each receiving antenna comprises a receiving multimode fiber and a receiving micro-lens. A transmitting micro-lens is positioned in the center of each receiving micro-lens. By the optical transmitting antenna system and the beam control method thereof, the mobile communication of a near-earth atmospheric laser system is well realized, dependence on a complex acquisition pointing and tracking (APT) system is reduced, and communication reliability is improved.

The invention discloses a symmetrical all-fiber Fabry-Perot sensor, a first single-mode fiber is welded with a first multi-mode fiber, and a second single-mode fiber is welded with a second multi-mode fiber; tail ends of the first multi-mode fiber and the second multi-mode fiber are provided with concave cavities; the concave cavities of the first multi-mode fiber and the second multi-mode fiber are in butt joint with each other to form an FP cavity. According to the symmetrical all-fiber Fabry-Perot sensor and the manufacturing method thereof provided by the invention, the structure is small and exquisite, manufacture is easy and cost is low, the fiber sensor can utilize a chemical corrosion method to obtain a long Fabry-Perot cavity, is symmetrical in structure and low in stripe fineness, is little affected by temperature, and can utilize a phase method based on Fourier transform to realize measurement of pressure and strain under high temperature.

The invention provides a single-pixel camera system based on a multi-mode optical fiber, which has the advantages of high signal-to-noise ratio, simple optical path structure and high expansibility. The single-pixel camera system mainly comprises a DMD modulation portion, a data acquisition portion and an algorithm recovery portion. Specifically, the traditional single-pixel camera system converges light modulated by a DMD to a light sensitive surface of a unit detector by using a lens, then the light is converted into a corresponding light intensity value through A/D conversion, and imaging can be performed by inputting the light intensity value into a recovery algorithm by combining an observation matrix. The method utilizing the general lens often brings great noise interference to an experiment result, and the signal-to-noise ratio of the system is reduced by influences of the aberration generated by convergence of the lens for the space light, the dispersion of light and the ambient light in the light propagation process in addition to system noise and environmental noise. The utilization of the multi-mode optical fiber on the basis not only can reduce the loss of light transmission in the space, but also can realize single-pixel imaging in a specific band. Only an optical fiber with a specific transmission wavelength is required to be replaced.

Methods for modifying multi-mode optical fiber manufacturing processes are disclosed. In one embodiment, a method for modifying a process for manufacturing multi-mode optical fiber includes measuring at least one characteristic of a multi-mode optical fiber. The at least one characteristic is a modal bandwidth or a differential mode delay at one or more wavelengths. The method further includes determining a measured peak wavelength of the multi-mode optical fiber based on the measured characteristic, determining a difference between the target peak wavelength and the measured peak wavelength, and modifying the process for manufacturing multi-mode optical fiber based on the difference between the target peak wavelength and the measured peak wavelength.

The invention provides a line cavity laser with super-narrow line width based on parallel feedback, which comprises a DFB (Distributed Feedback) laser, a 90:10 coupler, a reflection unit, multiple sections of single mode optical fibers and multiple mold optical fibers, wherein the DFB laser and the 90:10 coupler as well as the 90:10 coupler and the reflection unit are respectively coupled through an optical fiber structure composed of the single mode optical fibers and the multiple mold optical fibers.

The invention relates to the technical field of optical fiber sensor medical devices, in particular to an OCT imaging compound micro probe integrated with optical fiber sensing multi-parameter measuring, and discloses a preparation method of the composite micro probe. The probe comprises a multi-core optical fiber, a side-hole optical fiber, a single-mode optical fiber and a multi-mode optical fiber which are sequentially welded, the multi-mode optical fiber comprises a central axis fiber core and an eccentric fiber core, the central axis fiber core and the fiber core of the single-mode optical fiber are welded at two ends of the fiber core of the side-hole optical fiber, photoetching FBG optical grating is arranged on the eccentric fiber core, and the front end of the eccentric fiber coreand the rear end of a side-hole air cavity on the side-hole optical fiber are aligned to further form an F-P air cavity; the front end of the multi-mode optical fiber is fused with a Bell ball. The structure of the probe is reasonable, sensitive units of FBG grating, F-P air cavity are integrated, a Bell ball focusing lens is fused through the multi-mode optical fiber, the definition of an OCT imaging observing image can be effectively improved, body tissue detecting imaging is conducted while measuring of parameters of temperature, pressure and the like is conducted, the overall structure iscompact, the size is small, and the probe has significant meaning in in vivo microvessel disease diagnosis and the like.

The invention discloses a demodulating device for an optical fiber Young interference optical path difference based on low coherent interference. The demodulating device comprises a wideband light source, a 3dB coupler, a sensing interferometer, a demodulating interferometer, a calibration interferometer and a line array camera, wherein a multimode optical fiber is adopted in a light path formed by the components in sequence for optical signal transmission. A demodulating method mainly comprises the steps of optical path difference sensing, optical path difference demodulating and optical path difference calibration. Compared with the prior art, the demodulating device and the method integrate modes of space scanning and time scanning to conduct low coherent interference optical path difference demodulating; no mechanical movement is available; the stability is high; compared with the time scanning, the demodulating precision is not affected by moving precision of a scanning motor; the nano-level high precision demodulating can be realized; the optical path difference calibration of an overall system is realized by adjusting the optical path difference; in addition, a nano displacement platform is adopted to control the output optical path difference effectively; an optical path difference demodulating interval of the overall system is amended; and with the adoption of an optical fiber interferometer structural form, the system adjustment is facilitated and the working stability is high.

The invention relates to a high-speed measurement method and device of space-time spectral information of a multi-mode optical pulse cluster. The method comprises a step of using a mode demultiplexer to convert light components of different optical fiber modes in the multi-mode optical pulse cluster into an optical fiber fundamental mode and decomposing the optical fiber fundamental mode into different single-mode optical fibers, a step of using an adjustable attenuator to carry out appropriate attenuation on light in each path of single-mode optical fiber, a step of coupling light into a single-mode optical fiber by using an optical fiber delay line and a coupler and mapping space mode information to a time domain, and a step of mapping information of spectrum to the time domain by using a dispersion optical fiber and carrying out detection by using a high-speed photoelectric detection system to realize the high-speed measurement of spectral information of each mode. The method and the device can be used for the research of an instantaneous pulse nonlinear effect in a multi-mode optical fiber ultra fast laser system.

The invention relates to a Raman spectrometer, and particularly discloses an optical fiber microprobe of a tip-enhanced Raman spectrometer, which includes a box body and a circuit part, wherein the circuit part is arranged in the box body; a white light imaging optical path, a laser optical path and a signal collecting optical path are arranged on the circuit part; all the white light imaging optical path, the laser optical path and the signal collecting optical path adopt optical fiber conduction; an optical fiber, a first beam splitter, a second beam splitter, a microlens, a lens, a reflector, a camera and a pull rod are arranged on the white light imaging optical path; a laser, a single mode polarization maintaining optical fiber, a optical fiber coupler, a laser-line bandpass filter plate and a 45 DEG edge filter plate are arranged on the laser optical path; and a 0 DEG edge filter plate, optical fiber coupler, a multimode fiber and a spectrometric detector are arranged on the signal collecting optical path. The invention has the advantages that the optical fiber microprobe of the tip-enhanced Raman spectrometer has simple optical path and small volume, can conveniently replace laser wave length and polarization direction, is highly stable, can be combined with any scanning probe microscope, can conveniently switch the excitation mode, and can improve the integral stability and the operation convenience of the TERS instrument.

A multi-mode optical fiber link is described. The multi-mode optical fiber link includes a first spatial mode converter that is coupled to a first single mode optical fiber. The first spatial mode converter conditions a modal profile of an optical signal propagating from the single mode optical fiber to the first spatial mode converter. A multi-mode optical fiber is coupled to the first spatial mode converter. A second spatial mode converter is coupled to an output of the multi-mode optical fiber and to a second single mode optical fiber. The second spatial mode converter reduces a number of optical modes in the optical signal. Both the first and the second spatial mode converters increase an effective modal bandwidth of the optical signal.