908 results about "All fiber" patented technology

A fiber laser amplifier system including a master oscillator that generates a signal beam. A splitter splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam.

By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

A source and/or method of generating quantum-correlated and/or entangled photon pairs using parametric fluorescence in a fiber Sagnac loop. The photon pairs are generated in the 1550 nm fiber-optic communication band and detected by a detection system including InGaAs/InP avalanche photodiodes operating in a gated Geiger mode. A generation rate>10³ pairs/s is observed, a rate limited only by available detection electronics. The nonclassical nature of the photon correlations in the pairs is demonstrated. This source, given its spectral properties and robustness, is well suited for use in fiber-optic quantum communication and cryptography networks. The detection system also provides high rate of photon counting with negligible after pulsing and associated high quantum efficiency and also low dark count rate.

An all-fiber combiner device is described for combining multiple high power inputs, such as high power laser inputs. The device includes a first tapered fiber section made from fibers that allow for efficient size reduction of the optical signals. The output of the first tapered fiber section may then be coupled to a multimode output fiber for delivery of the combined power beam. Alternately, the first tapered section can be coupled to a second, multimode, tapered section, which provides further size reduction of the core for splicing into a final output fiber, while adding cladding to the main fiber.

An all-fiber erbium laser oscillating in a passive Q switched mode. The laser includes a crystal saturable absorber that may be Co²⁺:ZnSe or Cr²⁺:ZnSe. In preferred embodiments continuous pumping or short pulse pumping may be utilized. The laser is characterized by low threshold high-power, short-pulse generation. In preferred embodiments the threshold is only about 20 mW. The crystals are bleached at extremely low intensity, of about 0.8 kW/cm² and provide moderate relaxation time of the excited state (290 μs) within a spectral range of about 1400-1800 nm. The simplicity of the design and low cost of that laser 2000).

A fiber laser amplifier system including a beam splitter that splits a feedback beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam. A beam sampler samples a portion of the output beam from the end cap and provides a sample beam. A single mode fiber receives the sample beam from the beam sampler and provides the feedback beam.

An autocorrelator apparatus and method for economically measuring physical properties of an object where the measurement path is at least semi-translucent to light, such as thicknesses in multilayered optical structures, group index of refraction, and distance to a surface. The apparatus includes a non-coherent light fiber interferometer and an optional coherent light fiber interferometer in association so as to share PZT fiber modulators. Thickness and boundary extent measurements can be made, for example, of solids, liquids, liquids moving along a horizontal plane, or liquids flowing down a plane.

The invention provides an all-fiber testing device for testing the polarization crosstalk of an optical device. The all-fiber testing device comprises a wide-spectrum light source (501), a polarizer (511), a to-be-tested polarizing device (522), an optical path correlator (530), a difference detector (550) and a photoelectric signal conversion and signal recording device (560), wherein the wide-spectrum light source (501) is connected with the to-be-tested optical fiber device (522) through the polarizer (511) and a first rotary connector (521) and is connected with the optical path correlator (530) with a polarization beam splitting Michelson structure through a second rotary connector (523); and the optical path correlator (530) is connected with the polarization difference detector (550) through a third rotary connector (541) and is connected with an interference signal detecting and processing device (560). The all-fiber testing device has the advantages of small size, high measurement accuracy, high temperature and vibration stability and the like, so that the all-fiber testing device is widely applied to high-accuracy measurement and analysis of the polarization performance of the optical device.

An all fiber optic laser based scanning system for real time terrain mapping under degraded visual conditions is disclosed. A laser output is modulated to achieve a desired pulse width and pulse repetition frequency (PRF) and the modulated signal is amplified. The amplified optical signals are split into N channels that correspond to N elements of an optically phased array that steers light by modulating the phase of light entering and exiting the optical system. By applying a linear phase shift across the beam's wave front, the light propagating along the system's optical axis is steered to an off-axis angle. A real time map of an underlying terrain is accomplished by sweeping the N channel array across the terrain while collecting range information from each scan grid.

The invention discloses a tip clearance measurement method based on all-fiber tip timing. The method comprises the following steps: converting measurement on length measurement in a triangle method into measurement on a tip timing signal; adopting two fiber bundle type timing sensors, and enabling emission fibers in the timing sensors to emit two beams of auto-collimation emergent light with different wavelengths; enabling receiving fibers in the timing sensors to receive moment signals when leaves approach and leave a measurement region; monitoring the rotating speed of a rotor in real time by a rotating speed synchronization sensor; performing high-speed signal acquisition and circuit module processing on all the sensor signals, and reversely calculating a distance between the end face of each sensor and each leaf tip by an upper computer through a math model. According to the tip clearance measurement method, a clearance value is ingeniously converted into a tip timing signal relevant to the clearance value, so that a measurement system is irrelative to most environmental factors such as the leaf and electromagnetic interference, and the interference resistance and the clearance measurement precision of the system are improved.

An improved method and apparatus for mode-locking a fiber laser at a pre-selected frequency wherein a doped fiber segment contains a narrowband FBG and an electro-optically tuned FBG, thereby making obsolete the need for an EOM to modulate the laser's wavelength. The present invention also provides a method and apparatus for mode-locking a fiber laser at a variable frequencies wherein a doped fiber segment contains two electro-optically tuned FBG's. The electro-optically tuned FBG may be fabricated by a thermal poling process.

The invention discloses an all-fiber direct detection anemometric laser radar system and a closed-loop control method thereof. The system comprises an optical emission part, a frequency locking part, an emission part and a receiving part, wherein the optical emission part is used for emitting a modulated and amplified laser pulse; the frequency locking part is used for detecting the laser frequency variation, feeding back to the laser emission part, adjusting the laser wavelength and further realizing the function of locking the laser wavelength according to the deviation; the emission part is used for enabling the laser beam to point to the detection zone of the atmosphere, coupling the atmospheric back scattered light to a receiver through an optical telescope and modulating the near field signal strength; the receiving part is used for filtering out sun background from a signal and dividing the signal into two paths, one path of signal passes through a Fabry-Perot interferometer, the other path of signal is used as energy reference, the transmittance is obtained through the ratio of the signal intensities of the two paths of signal, and the wind velocity is obtained through inversion according to Doppler frequency shift. The laser radar adopts an all-fiber structure and has the advantages of small size and light weight, the manufacturing cost of the radar is low, the laser radar is controlled through a 3-level closed-loop, and the environmental adaptability and working stability of the laser radar are improved.

A fiber laser cavity that includes a laser gain medium for receiving an optical input projection from a laser pump. The fiber laser cavity further includes a positive dispersion fiber segment and a negative dispersion fiber segment for generating a net negative dispersion for balancing a self-phase modulation (SPM) and a dispersion induced pulse broadening/compression in the fiber laser cavity for generating an output laser with a transform-limited pulse shape wherein the wherein said laser gain medium further comprising a double cladding Ytterbium-doped Photonics crystal fiber (DC YDPCF) for amplifying and compacting a laser pulse. The fiber laser cavity further includes a polarization sensitive isolator and a polarization controller for further shaping the output laser.

The invention discloses a 2 mu m all-fiber coherent laser Doppler wind finding radar system, which consists of a 2 mu m off-axis Cassegrain optical antenna system, a 2 mu m laser beam splitting system, a 2 mu m seed implantation laser amplifier, a 2 mu m monitoring detector system, and a 2 mu m balanced heterodyne detection system. The system overcomes the defect of ambient interference existing in a free space optical path, overcomes the influence of shot noise on heterodyne reception signal-to-noise ratio, and solves the problems of all fiber and miniaturization of the 2 mu m all-fiber coherent laser Doppler wind finding radar system, so that the 2 mu m all-fiber coherent laser Doppler wind finding radar system has a more compact structure. In addition, the system has the characteristics of safe laser for human eye, optical path connection by adopting flexible optical fiber devices, high operability and stability, low cost, good real time, long effectively measured distance, high measurement accuracy (speed measurement and distance measurement) and the like, and has high practical value in the field of coherent laser Doppler wind finding radar.

A method and an apparatus to photoinduce a grating or other type of modulated refractive index change in a photosensitive optical medium such as optical fiber. The resulting grating has a variable and controllable intensity profile and average value of the index change. The modulated refractive index change is photoimprinted in the medium in a series of writing steps, each comprising exposing a segment of the medium to a writing beam for a predetermined exposure time. To change the modulation intensity from step to step, the angle of incidence of the writing beam is dithered for an appropriate fraction of the exposure time at each step. This allows to control the amount of incident light on the medium for each step. If the exposure time is the same for each writing step, the average value of the index change may be kept constant avoiding undesired structure in the grating frequency response.

An embedded flight sensor system having a laser and one or more flight sensors in optical communication with the laser plus a data processing device in optical communication with the flight sensors. The flight sensors may be laser based optical components such as a fiber Bragg grating in combination with an optical detector, a spectroscopy grating and detector or an optical detector associated with catch optics. The parameters sensed by the flight sensors may be used to determine any flight parameter. Representative flight parameters include but are not limited to an airframe or external surface temperature, airstream velocity, combustion zone temperature, engine inlet temperature, a gas concentration or a shock front position.

The present invention discloses an all-fibre digital clinometer. It is composed of central processor, signal processor, counter, optical cable capstan winch, tension sensor, derrick and letting-in probe. Said invention also provides their connection mode, and also provides the working principle of said all-fiber digital clinometer and its operation method.

The invention belongs to the technical field of all-fiber current transformers, and particularly relates to a high-precision high-reliability and all-fiber current transformer. A redundancy design method adopting active optical devices is applied so that output optical power of light source units is enabled to be more stable and stability of light source average wavelength is enhanced. A depolarization head is additionally arranged in an optical path system so that stability and measurement precision of the optical path system can be enhanced. Two beams of light are converted into electric signals to be transmitted to a signal processing unit by utilizing correlation of output light of the two output ends of a second single-mode coupler through a digital signal processing unit, and suppression of light source intensity noise is realized by utilizing a digital circuit subtraction method so that signal-to-noise ratio is enhanced and measurement precision of the system is enhanced. A low birefringence optical fiber Verdet constant and a transformation ratio error generated by change of wave plate phase delay along with temperature are enabled to be mutually compensated via an all-fiber current transformer transformation ratio temperature error automatic compensation technology so that full-temperature measurement precision of the system is enhanced.

This invention relates to a load automobile hub axle tube whole fiber forging and shaping process and its mould. It is characterized by the following: adopting solid material; finishing hub axle tube surface and deep hole extrusion shaping to get the whole fiber metal flow wire along axle direction and the inner hole is shaped by extrusion without process.

The invention discloses an all-fiber current sensor consists of a 3x3 polarization-maintaining fiber coupler. One embodiment of the invention, a straight-through type interferometric all-fiber current sensor, comprises a light source, a 3x3 polarization-maintaining fiber coupler, fiber polarizers, a 1/4 fiber wave sheet and a transduction fiber ring. The light source is connected with one end of the 3x3 polarization-maintaining fiber coupler; the two ports of the 3x3 polarization-maintaining fiber coupler are respectively connected with two fiber polarizers; and the other ends of the two fiber polarizers are respectively connected with the transduction fiber ring by the 1/4 fiber wave sheet; one port of the 3x3 polarization-maintaining fiber coupler is vacant; and the rest two ports of the 3x3 polarization-maintaining fiber coupler are respectively connected with a signal processor by two photoelectric detectors. In addition, another embodiment of the invention, a reflection type interferometric all-fiber current sensor, also uses the 3x3 polarization-maintaining fiber coupler. The all-fiber current sensor avoids phase differences made artificially and makes the current transduction system woke more stably.