31 results about "Brillouin fiber laser" patented technology

The present invention relates to technical field of optical fiber sensing. The present invention provides a bi-directional dual wavelength simultaneous lasing brillouin fiber laser, wherein the laser comprises a first optical fiber 1, a lumped loss component 3, a second optical fiber 2 and a coupling device 4, wherein the coupling device 4 is provided with a first terminal port 5, a second terminal port 6, a third terminal port 7 and a fourth terminal port 8; all components constitute a mixed ring cavity; the two pieces of optical fiber are provided with different brillouin frequency excursion characteristic; two narrow line-width lasers with same wavelength are injected into the ring cavity by the first and second terminal port of the coupling device 4; two lasing brillouin Stokes waves are generated in clockwise and anti-clockwise direction respectively and output from the first and the second terminal port respectively so as to realize bi-directional lasing, and only one lasing wavelength in each lasing direction.

A distributed optical fiber sensing device based on a Brillouin fiber laser, including a narrow linewidth pump laser, an erbium-doped fiber amplifier, a pulse signal generator, a polarization scrambler, an optical isolator, etc., using the Brillouin fiber laser The dual output ports output two beams of light waves with a frequency difference of about one Brillouin frequency shift. One beam of frequency-tunable Brillouin laser is pulse-modulated as pump light, and the other beam is used as continuous probe light. The adjustable Brillouin laser output is realized by the temperature controller of the Brillouin laser cavity. The frequency-tunable pulsed pump light and the continuous probe light undergo Brillouin interaction in the sensing fiber. The signal processing at the back end of the sensing system is the same as that of the general Brillouin optical time domain analysis system. The pump and probe light are provided by the Brillouin fiber laser, which can save the adjustable microwave source and supporting modulator in the general Brillouin optical time domain analysis system, greatly reducing the cost and complexity of the entire system. Facilitate system optical integration and packaging.

The present invention relates to a fiber laser sensor, in particular to a forward Brillouin fiber laser sensor based on stimulated Raman, including a tunable single-frequency laser, an erbium-doped fiber amplifier, a polarization controller, an optical coupler, a single Mode optical fiber, temperature / strain control system, polarization beam combiner, photodiode, spectrum analyzer, spectrometer; temperature / strain control system consists of optical fiber fixing fixture and heater. The invention has a reasonable design, uses a forward-stimulated Raman-like Brillouin fiber laser, and detects the stimulated Raman-like scattering-like R 0m The frequency shift of the Brillouin mode realizes temperature and strain sensing with adjustable sensitivity.

The invention discloses a multi-wavelength Brillouin fiber laser with a frequency interval of 44 GHz, including a narrow-linewidth semiconductor laser, a four-port fiber coupler, a first four-port optical circulator, a first single-mode fiber, and a second single-mode fiber , the second four-port optical circulator and the erbium-doped fiber amplifier, wherein the first four-port optical circulator, the first single-mode fiber, the second single-mode fiber and the second four-port optical circulator together form a fourth-order Brillouin Frequency shifter, the narrow-linewidth laser used as Brillouin pump passes through the fourth-order Brillouin frequency shifter to generate Brillouin Stokes light whose frequency is shifted down to 44GHz, the Brillouin Stokes light After being amplified by the erbium-doped fiber amplifier, part of the light is output through the fiber coupler, and the other part of the light enters the fourth-order Brillouin frequency shifter for cyclic downshifting of the 44GHz frequency, so that the ring cavity structure can generate wavelength channels with a frequency interval of 44GHz. Multi-wavelength Brillouin laser.

A tunable ultra-narrow linewidth optoelectronic oscillator based on a random Brillouin fiber laser is provided, comprises a first tunable laser (1), a second tunable laser (2), a coupler (3), a beam splitter (4), an intensity modulator (5), an erbium-doped fiber amplifier (6), a first circulator (7), a highly nonlinear optical fiber (8), a second first circulator (9), a single-mode optical fiber (10), a photodetector (11), a power divider (12) and a phase-locked loop system (13) which constitute a real-time feedback system so that the two lasers emitted by the two tunable lasers have a fixed and stable phase difference. The microwave signal with adjustable center frequency and narrow linewidth can be generated by using the modulating characteristic of intensity modulator, nonlinear characteristic of high nonlinear fiber, feedback characteristic of single mode fiber, wavelength tunable characteristic of tunable laser and microwave generation performance of photoelectric oscillator.

The invention provides a kHz-level single-passband microwave photonic filter comprising a laser, a first optical coupler, a single sideband suppression carrier modulation module, a single sideband modulation module, a microwave signal source, a first optical amplifier, a second optical amplifier, a second optical coupler, a single-frequency Brillouin fiber laser, a photodetector and a vector network analyzer. According to the invention, the ultra-narrow single-passband microwave photonic filtering is achieved by using a gain cavity of the single-frequency Brillouin fiber laser, the technical problem that an existing microwave photonic filter cannot achieve single-passband filtering below the order of magnitude of MHz is solved, the 3dB bandwidth of the device achieves a significant breakthrough and can reach the order of magnitude of kHz, and at the same time, the kHz-level single-passband microwave photonic filter has the advantages of stable center frequency is stable, tunability andhigh out-of-band rejection ratio.

A fiber temperature sensor based on multi-wavelength Brillouin fiber laser is made by using the Brillouin gain effect of fiber, the amplification effect of erbium-doped fiber, the temperature effect of multi-level Brillouin scattered light and the principle of heterodyne beat frequency demodulation Fiber optic temperature sensors, including narrow-linewidth single-frequency lasers, optical splitters, polarization controllers, optical isolators, optical circulators, single-mode sensing fibers, Erbium-doped fiber amplifiers, unpumped Erbium-doped fibers, high-speed optoelectronics detectors, spectrum analyzers. The invention has the advantages of large number of wavelengths, narrow line width, fixed wavelength interval, and stable output. The single-mode fiber provided for the gain of the fiber laser is used as a temperature sensing detection unit to perform heterodyne beat frequency resolution on high-order Stokes waves. Adjust the detection to achieve high-precision and high-sensitivity temperature measurement.

A broadband tunable multi-wavelength Brillouin fiber laser belongs to the field of fiber lasers and aims to solve the problem that the present multi-wavelength Brillouin fiber laser can not adjust the output wave constant. The technical scheme is as follows: a tunable Brillouin pumping is connected with an input / output circulator; the input / output circulator is connected with a coupler and an isolator; all output light is output via the isolator; the coupler is connected with a polarization controller; the polarization controller is connected with a wavelength division multiplexer, and the polarization controller can tune polarization loss of signals in a cavity to realize tuning of the wave constant of output signals; the wavelength division multiplexer is connected with an Er-doped fiber; a 980 nm pump laser enters into the Er-doped fiber to produce gain and amplify light signals in the cavity through the wavelength division multiplexer; the Er-doped fiber is connected with the coupler; the coupler is connected with a monomode optical fiber; the monomode optical fiber is connected with a reflective circulator; and two ports of the reflective circulator are connected for reflecting transmission light in the monomode optical fiber.

The invention discloses a forward Brillouin fiber laser based on stimulated Raman, including a tunable single-frequency laser, an erbium-doped fiber amplifier, a polarization controller, an optical coupler, a single-mode fiber, and a polarization combiner. Photodiodes, spectrometers, spectrometers. A kind of forward Brillouin fiber laser based on stimulated Raman described in the present invention, its advantages and positive effects are embodied in that, compared with the existing Brillouin fiber laser, the present invention utilizes equal frequency intervals and Fiber core-dependent stimulated Raman-like R 0m mode, which improves the flexibility of resonator design and realizes a cavity-length-independent Brillouin fiber laser.

The invention relates to a fiber laser sensor, and specifically relates to a pump-free multi-wavelength Brillouin fiber laser sensor for low-frequency detection. The sensor solves the problems of low detection sensitivity, poor anti-interference capability and low measurement precision of the existing fiber laser sensor. The pump-free multi-wavelength Brillouin fiber laser sensor for low-frequency detection comprises a narrow line width single-frequency laser, a second one-way light divider, a low-frequency photoelectric detector, a spectrum analyzer and a resonant cavity; the resonant cavity comprises a semiconductor optical amplifier, an optical circulator, a polarization controller, an optical isolator, a first one-way light divider and a Sagnac circular endoscope; and the Sagnac circular endoscope comprises a double-way light divider and a high nonlinear sensing fiber. The invention is applicable in the field of fiber sensors.