1071 results about "Optical fiber amplifiers" patented technology

The invention relates to a method for stripping residual pump light in a double-coated optical fiber, which comprises the steps of: removing an outer coating and a cladding layer of one section of the double-coated optical fiber at the output end of a full optical fiber laser; covering optical gel with high refractive index outside an inner coating of the section of the optical fiber, wherein the refractive index of the optical gel is higher than that of the inner coating of the double-coated optical fiber; leaking light transmitted in the inner coating out through the optical gel, and fully absorbing the leaded pump light with high power by a heat radiating device. The invention has the characteristics of compact structure and convenient integration, and can be applied to a high-power optical fiber laser or high-power optical fiber amplifier.

The invention discloses a fiber bragg grating array-based phase-sensitive optical time domain reflection device and method. The device includes a light source, a laser frequency adjustment module, a modulator, an optical fiber amplifier, a circulator, a sensing optical fiber, a light detector, a data acquisition module and a data processing module; the sensing optical fiber is provided with an optical fiber array formed by a plurality of FBGs (fiber bragg grating) which are arranged equidistantly; the laser frequency adjustment module is used for frequency adjustment of continuous light emitted by the light source; the continuous light is modulated by the modulator so as to form pulsed light; the optical fiber amplifier performs power amplification on the pulsed light; the sensing optical fiber is used for receiving and transmitting the pulsed light which has been subjected to power amplification; the light detector receives scattered light and reflected light; the scattered light and reflected light are acquired by the data acquisition module; and the data processing module generates interference signal frequency response spectrum and obtains the length variation quantity of the sensing optical fiber between two adjacent FBGs through processing. With the fiber bragg grating array-based phase-sensitive optical time domain reflection device and method of the invention adopted, strain quantitative detection can be realized, and high-spatial resolution measurement can be realized based on quantitative analysis.

A laser device which can be used as a light source for an exposure device, can be downsized, and is easy to maintain. A laser beam (LB6) emitted from a DFB (Distributed feedback) semiconductor laser, for example, and amplified by an optical fiber amplifier is passed through non-linear optical crystals (502, 503, 504) to be sequentially doubled in frequency to thereby generate an ultraviolet-region laser beam (LB5) consisting of an octuple wave. A GdYCOB, that is, Gd_xY_1−xCa₄O(BO₃)₃ crystal (0≦×≦1) is used for the non-linear optical crystal (503) for a double wave-to-quadruple wave conversion, and a KAB, that is, K₂Al₂B₄O₇ crystal for the non-linear optical crystal (504) for a quadruple wave-to-octuple wave conversion. The non-linear optical crystals (502-504) are all fine-tuned in phase match angle by temperature controllers (521-523) respectively.

The invention discloses a method for locking Raman gains of a target and a Raman OFA (optical fiber amplifier). The OFA comprises a coupler and a control unit, wherein the control unit comprises a gain locking module; and a detection circuit formed by a filter and an optical power detector is connected between the output end of the coupler and the input end of the control unit. In the method, the control unit is utilized to adjust the power of a pump laser, thus the power of detected OOB (out of band) ASE (amplified spontaneous emission) optical signals is consistent with that of the targeted OOB ASE optical signals, and the amplification gains of the target is locked. The optical path structure of the OFA is simple, the Raman gains can be configured flexibly in accordance with the circuit conditions, and the gains of the Raman OFA can be automatically controlled and locked.

A lidar includes CW laser light sources that oscillate CW laser light rays with wavelengths different from each other; an optical multiplexing coupler that mixes the CW laser light rays oscillated by the CW laser light sources; an optical branching coupler that splits the CW laser light passing through the mixing by the optical multiplexing coupler; a light modulator that modulates first CW laser light split by the optical branching coupler; and an optical fiber amplifier that amplifies the laser light modulated by the light modulator, in which a transmit-receive optical system irradiates a target with the laser light amplified by the optical fiber amplifier, and receives scattered light of the laser light by the target.

The invention discloses an optical frequency division multiplexing phase-sensitive optical time domain reflectometer which comprises a narrow line width laser, an optical fiber coupler, a phase modulator, a scrambler, an erbium-doped optical fiber amplifier, an acoustic optical modulator, an optical fiber circulator, a signal generator module, a trigger source, a double balance detector, a low pass filter, a data acquisition card, a computer and a long-distance sensing optical fiber. According to the optical frequency division multiplexing phase-sensitive optical time domain reflectometer, the fundamental contradictions between the measuring distance and sampling rate in a distributed sensing system can be solved, and remoter or higher-frequency vibration is detected; and moreover, due to amplitude and phase information, the characteristics of a vibration source are judged at the first time, and the early warning can be provided immediately.

The application provides a low noise fiber laser frequency combs device with controllable carrier envelope phase shift frequency. The low noise fiber laser frequency combs device with controllable carrier envelope phase shift frequency comprises an optical path structure and a circuit structure, wherein the optical path structure comprises an oscillator, an acousto-optic frequency shifter, an optical fiber amplifier, a pulse compressor, an optical fiber spread spectrum device and a coherent heterodyne beat device; and the circuit structure comprises a feed-forward circuit control phase device and a phase-locked loop circuit control repetition frequency device. The fiber laser oscillator can ensure long-time operation of a system, so that the stability of the system is superior to that of a system adopting a solid laser oscillator; through the technologies of optimizing intracavity net dispersion of the fiber oscillator, introducing an inner cavity modulator in the oscillator, adopting the feed-forward acousto-optic frequency shifter, and the like, the low noise fiber laser frequency combs device can be realized; and meanwhile, due to the application of the acousto-optic frequency shifter, the carrier envelope phase shift frequency of the optical frequency combs can be accurately regulated, so that the optical frequency combs device with precise phase position regulation and secular stability is provided for realizing applications such as optical frequency standard, attosecond science and non-linear optics.

A distributed optical fiber sensor based on Raman and Brillouin scattering is provided. The distributed optical fiber sensor includes a semiconductor FP cavity pulsed wideband optical fiber laser (11), a semiconductor external-cavity continuous narrowband optical fiber laser (12), a wave separator (13), an electro-optic modulator (14), an isolator (15), an Er-doped optical fiber amplifier (16), a bidirectional coupler (17), an integrated wavelength division multiplexer (19), a first photoelectric receiving and amplifying module (20), a second photoelectric receiving and amplifying module (21), a direct detection system (22), a narrowband optical fiber transmission grating (23), a circulator (24) and a coherence detection module (25). The temperature and the strain can be measured simultaneously, and the signal-to-noise ratio of the system is enhanced.

The invention discloses a long-distance distributed optical fiber vibration sensing system and a method thereof. The system comprises an induction system for inducting outside vibration events and a detecting and controlling system for detecting and controlling vibration signals; the induction system is connected with the detecting and controlling system. The induction system comprises a light source, a pulse modulator, an optical fiber circulator, a first optical fiber amplifier, and a light switch of a first optical fiber filter. The detecting and controlling system comprises a plurality of optical-electrical converters and a system control unit; the system control unit collects output light of the converters, analyzing the collected signals and judges whether the alarm is needed according to the analysis result. The invention adopts the optical switch technology to adopt time-division processing on backward Rayleigh scattering light which is reflected back, the dynamic range of the system is large, and the sensible distance can be tens of kilometers as high as possible, even hundreds of kilometers; and the invention adopts phase detecting technology and optical time domain reflection technology and can greatly improve detecting sensibility of the system and positioning precision.

The invention discloses a distributed ultrahigh-speed disturbance quantitative detection method. Ultrahigh-speed disturbance detection can be realized through a time division multiplexing method; and phase demodulation is carried out through phase demodulation methods such as Hilbert transformation and orthogonal transformation so as to be able to realize real-time detection on the disturbance position, frequency and amplitude. The invention further discloses a distributed ultrahigh-speed disturbance quantitative detection device, which comprises a pulse generator, a laser, a first coupler, a pulse modulator, an erbium-doped optical fiber amplifier, a circulator, an optical fiber sensing unit, a second coupler, a balance detector, a band-pass filter, a power amplifier and a data acquisition card. According to the invention, the repetition frequency of detecting light pulses is improved through a time division multiplexing technology, so that a reflecting grating based phi-OTDR system is enabled to realize ultrahigh-speed disturbance detection; and real-time detection for the disturbance position, frequency and amplitude is realized through the phase demodulation method by using a coherent detection structure and combining a phase unwrapping algorithm.

A distributed optical fiber sensing system based on the phase generated carrier technology comprises a narrow-linewidth laser device, a modulator, an optoisolator, an erbium-doped optical fiber amplifier, an optical circulator, a fiber grating, a sensing fiber, a Michelson interferometer, a carrier circuit, a photoelectric detector, a data acquisition card, a signal processor and a pulse generator. The input end of the modulator is connected with the output end of the narrow-linewidth laser device. The input end of the optoisolator is connected with the output end of the modulator. The input end of the erbium-doped optical fiber amplifier is connected with the output end of the optoisolator. A port a of the optical circulator is connected with the output end of the erbium-doped optical fiber amplifier. The fiber grating is connected with a port b of the optical circulator. The output end of the carrier circuit is connected with an electrical interface of the Michelson interferometer. The input end of the photoelectric detector is connected with the output end of the Michelson interferometer. One input end of the data acquisition card is connected with the output end of the photoelectric detector, and the other input end of the data acquisition card is connected with the output end of the carrier circuit. The input end of the signal processor is connected with the output end of the data acquisition card. The input end of the pulse generator is connected with the trigger input end of the data acquisition card, and the output end of the pulse generator is connected with an electrical interface of the modulator.

The invention relates to a full duplex cat eye reverse modulation recovery free space laser communication system, belongs to the technical field of wireless communication, and solves the problem of low transmission rate of the system in the prior art. A laser I and a transmitting data source are both connected with a DPSK (differential phase shift keying) modulator, the DPSK modulator and a laser II are both connected with an optical fiber amplifier I, two communication lights are amplified and then connected with a port a of a fiber circulator, a port b of the fiber circulator is connected with an optical antenna, a port c of the fiber circulator is connected with a photoelectric detector I, the photoelectric detector I is connected with a DPSK modulator I, a cat eye optical system is coaxially arranged with the optical antenna, an optical filtering beam splitter is arranged between the cat eye optical system and a laser collimating lens and forms an angle of 45 degrees with the cat eye optical system, the laser collimating lens is connected with a port d of a fiber circulator II, a port e of the fiber circulator II, an optical fiber amplifier II and the DPSK modulator II are sequentially connected, the other end of the DPSK modulator is connected with a port f of the fiber circulator II, and a photoelectric detector II is connected with the DPSK modulator.

The invention discloses a microwave signal optical fiber stationary phase transmission system based on a microwave phase shifter. The system comprises a central station, a far end and a single-mode optical fiber. The central station is connected with the far end through the single-mode optical fiber. The central station is composed of a semiconductor laser device, a dual-drive Mach-Zehnder modulator, a microwave signal source, a first power divider, a first optical filter, an erbium-doped optical fiber amplifier, an optical coupler, a first array waveguide grating, a first photoelectric detector, a frequency eliminator, a second power divider, an optical source, a strength modulator, a second optical filter, an optical circulator, a second photoelectric detector, a first electric mixer, a band-pass filter, a second electric mixer, a low-pass filter and a linear voltage amplification circuit. The far end is composed of a second array waveguide grating, a third photoelectric detector and a Faraday polariscope. According to the invention, the advantage of low building and maintenance cost can be realized; and the phase jitter of microwave signals can be extracted and fed back on a real-time basis.

An optical amplifier includes an erbium doped fiber of which at least one of a core part and a clad part is doped with erbium, excitation light sources or exciting the optical fiber, optical means for inputting excitation light from the excitation light source and signal light to the Er-doped fiber, and an optical isolator. The erbium doped fiber is a 1.58 mum band optical fiber having an equivalent fiber length as a product of a fiber length (m) and an erbium doping concentration (ppm by weight), which length provides a signal gain obtained at a wavelength of the excitation light source used for excitation of the erbium doped fiber of more than a predetermined practical reference value.

The invention relates to a device and a method for generating microwave signals by using a multi-wavelength Brillouin laser. An existing device obtains a high frequency difficultly. The device of the invention comprises an adjustable narrow-band light source, two isolators, three couplers, an erbium-doped optical fiber amplifier, two optical fiber circulators, a Sagnac loop mirror, an optical fiber Bragg grating and a photodetector. The adjustable narrow-band light source is in optical connection with the isolators; the isolators are in optical connection with the couplers; outputs of the couplers are in optical connection with another coupler respectively; one of optical paths is provided with the erbium-doped optical fiber amplifier, the two optical fiber circulators and the Sagnac loop mirror. The method for generating the microwave signals by using the device comprises the following steps that: pump spectrum light emitted by the adjustable narrow-band light source is split into two paths of pump spectrum light after passing through the isolators and the couplers, one path of the pump spectrum light performs beat frequency with the other path of the pump spectrum light after outputting single-channel high-order Stocks light so as to obtain high-frequency microwave signals. The device and the method change the wavelength of the pump spectrum light to make a multi-wavelength pass band continuously adjustable.

The invention discloses a high bandwidth tunable double-passband microwave photon filter, belongs to the field of microwave photonics, and relates to the high bandwidth tunable double-passband microwave photon filter based on high non-linear optical fiber excited brillouin scattering effects and multiple pumping signals. The filter consists of a first laser, a first phase modulator, an opto-isolator, a vector network analyzer, a high non-linear optical fiber, a second laser, a strength modulator, a microwave signal source, a second phase regulator, a pulse code generator, an erbium-doped optical fiber amplifier, an optical circulator and a photoelectric detector. The filter is based on phase modulation and excited brillouin scattering effects caused by two pumping signals, and thus double-passband output of the microwave photon filter is achieved. By changing the frequency of the two pumping signals, the frequency of two passband centers can be randomly modulated within a certain frequency range. Through binary phase shift keying modulation on the pumping signals, the bandwidth of the pumping signals can be changed, and thus adjustment on the output bandwidth of the filter is achieved.

The invention provides a high non-linear optical fiber excited Brillouin scattering effect and amplitude ratio based microwave frequency measurement method and device and belongs to the technical field of microwave photonics. The device provided by the invention is composed of a tunable laser, a coupler, a phase modulator, a strength modulator, a vector network analyzer, an opto-isolator, a high non-linear optical fiber, a circulator, an erbium-doped optical fiber amplifier, a microwave signal source, a DC voltage stabilizing power source and a photoelectric detector. The frequency range of to-be-detected microwave signals can be enlarged through increasing bandwidths of the strength modulator and the phase modulator and enlarging the scanning range of the vector network analyzer and measurement precision can be improved through reducing noise in optical links and increasing the magnitude of energy transfer of excited Brillouin scattering effect. According to the invention, an amplitude ratio function curve is constructed based on the high non-linear optical fiber excited Brillouin scattering effect and a frequency value of to-be-detected microwave signals is obtained through the amplitude ratio function curve. Therefore, the measurement precision is improved.

There is provided a method and apparatus for improved efficiency in optical fiber lasers. Specifically, there is provided a system that increases the efficiency of cladding pumped optical fiber amplifiers through a seeding technique.

The multi-core optical fiber amplifier according to an exemplary embodiment of the present invention having the above configuration includes: a double clad multi-core optical fiber including a plurality of cores, an internal cladding enclosing the plurality of cores, and an external cladding enclosing the internal cladding; a pumping light source outputting pumping light; an optical fiber to which pumping light from the pumping light source is input; and a wavelength division multiplexing coupler coupling the optical fiber with the double clad multi-core optical fiber to apply the pumping light input to the optical fiber from the pumping light source to the double clad multi-core optical fiber.

A lateral pumped fiber structure comprises: at least one active optical fiber, which is used to generate laser or amplify the laser; at least one passive optical fiber, which is used to connect a pumping source. The active optical fiber and the passive optical fiber form an optical contact in a radial direction. The manufacturing method of the lateral pumped fiber structure comprises the following steps: 1) respectively preparing an active optical fiber performing rod and a passive optical fiber performing rod; 2) respectively performing wire drawing to the prepared active optical fiber performing rod and the passive optical fiber performing rod and making the active optical fiber and the passive optical fiber; 3) coupling at least one active optical fiber to at least one passive optical fiber so that the optical contact in a radial direction between the active optical fiber and the passive optical fiber can be formed. By using the fiber structure of the invention, pumping efficiency is high; a manufacturing technology and coupling equipment are simple; costs are low. The fiber structure of the invention is especially suitable for a high power optical fiber laser and an optical fiber amplifier.

The invention relates to the field of optical fiber sensing, specifically a phase-light time domain reflection device and method based on heterodyne detection phase demodulation. The device consists of a narrow linewidth laser, an optical fiber coupler with a coupling model of 1*2, a polarization controller, a sound-light modulator, an erbium-doped optical fiber amplifier, a narrow-band optical fiber filter, a first variable optical attenuator, a three-port circulator, a sensing optical fiber, an optical fiber coupler with a coupling model of 2*1, a photoelectric detector, a signal collection and processing module, an arbitrary waveform generator, a power amplifier, and a second variable optical attenuator. The device and method enable the heterodyne detection phase demodulation to be combined together, achieve external vibration sensing through direct phase demodulation, and are higher in sensitivity. In addition, the device and method employ a brand new direct phase modulation method to sense the external vibration, so the positioning method, compared with a conventional method, of each vibrating point is different.