42 results about "Raman amplification" patented technology

The invention discloses an optical fiber signal transmission system and method based on quantum noise encryption, and relates to the technical field of optical fiber communication, and the system comprises a composite modulation transmitting module, a dispersion compensation relay module, a coherent receiving module and a digital signal processor. The composite modulation transmitting module comprises an electro-optical modulator and a quantum noise randomization encoder; the dispersion compensation relay module comprises an adjustable dispersion compensator and a Raman amplifier; the coherent receiving module comprises a local oscillator laser and a 90-degree optical mixer; a digital signal processor includes a clock recovery unit and a maximum likelihood sequence detector. All the modules are sequentially connected and cooperatively work. And the adjustable dispersion compensator dynamically applies reverse dispersion compensation calculated based on a dispersion coefficient and a transmission distance according to the dispersion amount monitored in real time. According to the invention, through technologies of quantum noise encryption, dynamic dispersion compensation, Raman amplification, coherent reception and the like, safe and efficient transmission with single-wave 400Gbps and 100km transmission bit error rate less than or equal to 1 * 10 <-12 > is realized.

This invention discloses a multi-wavelength Brillouin and Raman random fiber laser based on tunable broadband Raman pumping, comprising a 1.5μm Brillouin pump, a 1.45μm tunable broadband Raman pump, a wavelength division multiplexer (WDM) I, and a passive fiber. The 1.45μm tunable broadband Raman pump includes a wavelength-tunable cascaded random Raman fiber laser, a WDM II, and a single-mode fiber I. The wavelength-tunable cascaded random Raman fiber laser is injected into the single-mode fiber I through the WDM II. This multi-wavelength Brillouin and Raman random fiber laser based on tunable broadband Raman pumping provides a 1.45μm tunable broadband Raman pump source by back-Raman amplification of the broadband seed light. Working together with the 1.5μm Brillouin pump, it can achieve ultra-wideband multi-wavelength random fiber laser output. By simultaneously tuning the output wavelengths of the Brillouin pump and the Raman pump, wavelength tuning of the broadband multi-wavelength random fiber laser can be achieved.

To provide an optical transmission device, an optical transmission system, and an optical transmission method that suppress an OSNR penalty due to return light.SOLUTION: An optical transmission device disposed at a fiber end of a single-core optical fiber and used when signal light is bidirectionally transmitted through the optical fiber, the optical transmission device comprising an optical transmitter configured to transmit first signal light in one direction belonging to the signal light, an optical receiver configured to receive second signal light in a reverse direction belonging to the signal light, and a controller configured to guide the first signal light transmitted from the optical transmitter to the optical fiber, An optical circulator configured to guide the second signal light from the optical fiber to the optical receiver; and a light source configured to output, to the optical fiber, excitation light that Raman-amplifies the second signal light to second optical power higher than first optical power of the first signal light.SELECTED DRAWING: Figure 2

The present invention provides an optical transmission system that can satisfy the XT required by the modulation method even if there is a difference in inter-core loss in the MCF. The optical transmission system of the present invention includes: a multicore optical fiber having a plurality of core regions, in which the loss is different between at least two cores; a front excitation light source and a combining section for causing Raman amplification excitation light in the same direction as the signal light to be incident on each core of the multicore optical fiber; a rear excitation light source and a combining section for causing Raman amplification excitation light in the opposite direction to the signal light to be incident on each core of the multicore optical fiber; characterized in that the intensity ratio of the front excitation light and the rear excitation light (the ratio of the power of the excitation light is set to a prescribed value) is controlled to reduce the variation in inter-core crosstalk (XT).

Systems and methods for operating a passive optical network (PON) extender. The methods comprise: receiving, by the PON extender, a first optical signal from a remote node device of a passive optical network via a first optical link; amplifying the first optical signal using a Raman amplifier of the PON extender to obtain a first Raman amplified optical signal; amplifying the first Raman amplified optical signal using a first optical amplifier of the PON extender to obtain an amplified uplink signal (wherein the first optical amplifier is different than the Raman amplifier); and passing the amplified uplink signal to an optical line terminal via a second optical link (wherein the optical line terminal is disposed locally at a hub site along with the PON extender).

A light source includes a seed light source and a booster amplifier. The seed light source outputs incoherent seed light having a predetermined bandwidth. The booster amplifier serves as a semiconductor optical amplifier that optically amplifies the seed light entered through a first end facet and outputs the amplified light through a second end facet. The booster amplifier has nL being set, which is the product of a refractive index n and a chip length L, so that relative intensity noise (RIN) and ripple are simultaneously suppressed in the amplified light.

The invention relates to the technical field of power equipment on-line monitoring and fault diagnosis, and discloses a GIL temperature distribution detection device based on double optical comb coding BOTDA, which comprises a GIL temperature sensing optical fiber, a double optical comb signal generation assembly, an optical transmission and detection assembly and an intelligent control and calculation system. The sensing optical fiber is attached to the surface of the GIL through a suspension type loose tube structure, and stress cross sensitivity is eliminated. The double-optical-comb assembly generates a pumping and detection optical comb loaded with random phase codes, and the peak-to-average power ratio is reduced to suppress modulation instability. The transmission assembly is matched with distributed Raman amplification to realize long-distance bidirectional injection, and optical downsampling is realized by using an optical comb beat frequency effect. And the control system executes closed-loop gain adjustment according to a comparison result of the detection power and a nonlinear threshold value, and calculates the temperature through space-time mapping. According to the invention, the contradiction between the signal-to-noise ratio and the nonlinear effect in long-distance sensing is solved, and high-precision and rapid GIL whole-line temperature monitoring is realized.

A Raman amplifier includes a first light source that outputs a primary pumping light, which propagates in a same direction as a propagation direction of a signal light, to an optical transmission line for Raman amplification, a second light source that outputs a secondary pumping light, which pumps and amplifies the primary pumping light and propagates in the same direction as the propagation direction, to the optical transmission line, and a control unit that controls a gain for the signal light by adjusting power of the secondary pumping light.

The application discloses a kind of based on external cavity stimulated raman amplification laser radar light source, including continuous laser, laser pulse modulation module, first optical amplifier, optical coupling isolation module, pump light source, pump combiner.The application increases pump light source and pump combiner, so that the pulsed light source of laser radar atmospheric detection and the laser output by pump light source are co-propagating in the same path in atmosphere, can further amplify pulsed light source, improve signal-to-noise ratio, extend laser radar detection distance.The laser light source of the application is used for laser radar atmospheric detection, when transmitting in atmosphere, beam is not constrained by optical fiber, nonlinearity in atmosphere is very weak, the power of pump light source can be very large (up to hundreds of watts), and the output signal light signal is not affected by the nonlinearity of optical fiber transmission.

The present invention provides an optical amplifier with high gain and improved flatness of gain and NF. [Solution] The optical amplification device comprises a plurality of Raman optical amplifiers, each having a Raman amplification optical fiber and an excitation light source unit that supplies excitation light to the Raman amplification optical fiber. The plurality of Raman optical amplifiers are connected in series. The product of the maximum value of the Raman gain efficiency of the Raman amplification optical fiber of the second Raman optical amplifier and its fiber length is smaller than the product of the maximum value of the Raman gain efficiency of the Raman amplification optical fiber of the first Raman optical amplifier, which is located before the second Raman optical amplifier, and its fiber length. The number of excitation light sources in the excitation light source unit of the second Raman optical amplifier is smaller than the number of excitation light sources in the excitation light source unit of the first Raman optical amplifier. At least one wavelength of the excitation light output by the excitation light source unit of the second Raman optical amplifier is different from at least one wavelength of the excitation light output by the excitation light source unit of the first Raman optical amplifier.

A fiber Raman amplifier system that includes a Raman pump module with a first pump laser at a first wavelength and a first power and a second pump laser at a second wavelength and a second power. The second wavelength is less than 10 nanometers different from the first wavelength. A ratio of the first power to the second power is adjusted to establish a Raman gain in a bandwidth.

This invention relates to the field of laser technology, and particularly to a Raman laser that outputs 9.2μm far-infrared laser light. It includes a laser pump beam splitting module, a first-order Raman laser generation module, a difference-frequency seed light preparation module, a laser beam combining and tuning module, a second-order Raman amplification module, and a laser collimation and separation module arranged sequentially along the optical path. The laser pump beam splitting module is used to achieve beam splitting and control of the 1064nm laser; the first-order Raman laser generation module is used to generate a 1.9μm first-order Raman laser from hydrogen; the difference-frequency seed light preparation module is used for difference-frequency preparation of the 9.2μm Raman seed light; the laser beam combining and tuning module is used for spatiotemporal overlap and beam combining of the pump light and the seed light; the second-order Raman amplification module is used for Raman amplification of the 9.2μm laser; and the laser collimation and separation module is used for collimation and separation of the target laser output. This invention utilizes a difference-frequency method to generate wavelength-matched far-infrared Raman seed light, and performs Raman amplification to ultimately obtain a 9.2μm far-infrared Raman laser with high pulse energy and high peak power.

The present invention relates to the technical field of communications, and provides a low-noise full-band fiber amplifier and a signal transmission system. The low-noise full-band fiber amplifier comprises a first wavelength division multiplexing component, a wavelength combining component, a first gain module, and a second gain module. The first wavelength division multiplexing component demultiplexes a full-band optical signal to obtain a first half-band optical signal and a second half-band optical signal. The first gain module performs forward doped fiber amplification and backward Raman amplification on the first half-band optical signal to obtain a first half-band gain signal; and the second gain module performs forward doped fiber amplification and backward Raman amplification on the second half-band optical signal to obtain a second half-band gain signal. The wavelength combining component multiplexes the first half-band gain signal and the second half-band gain signal to obtain a full-band gain signal. In the present invention, the entire band is divided into two major bands, and the two major bands are amplified respectively to equalize insertion losses of sub-bands; and by introducing backward Raman amplification, the low-noise full-band fiber amplifier is realized, and the backward Raman amplification is used to facilitate subsequent signal demodulation.

The invention relates to an anti-resonance hollow-core optical fiber Raman amplification system, which is characterized in that a fiber core of an anti-resonance hollow-core optical fiber is filled with mixed gas of methane and hydrogen, and Raman amplification with the gain not lower than 8dB, the gain flatness not higher than 1.5 dB and the noise index not higher than 3dB is realized in a C-waveband communication window of 1522-1567nm by combining a pumping technology of 1040-1090nm. Wherein the design of the anti-resonance hollow-core optical fiber provides a medium for signal light transmission, and provides a working place for a gas stimulated Raman scattering effect; based on the gas control module, the proportion of methane and hydrogen filled in the anti-resonance hollow-core optical fiber and the gas pressure can be accurately regulated and controlled, and the hydrogen can inhibit methane decomposition, so that the gain gas in the anti-resonance hollow-core optical fiber is kept in a stable state. The technical problem that the gas gain efficiency and the transmission stability are difficult to synergistically improve is effectively solved.

A wavelength converter includes: a first multiplexer that combines input signal light with wavelength-conversion excitation light; a second multiplexer that combines the signal light with Raman excitation light; a first nonlinear optical medium that generates wavelength-converted light of the signal light, based on a nonlinear optical effect; and a second nonlinear optical medium that amplifies wavelength-converted light of the signal light output from the first nonlinear optical medium. A wavelength of the Raman excitation light being a wavelength within an amplification band that allows Raman amplification of wavelength-converted light.

This invention provides a U-band high-energy square-wave pulsed Raman light source module. It first achieves initial stable amplification of the seed light through forward pumping with a 100-watt pump source, followed by high-energy main amplification through reverse pumping with a kilowatt-level pump source. Both stages of Raman amplification utilize highly nonlinear optical fibers as the gain medium to significantly enhance the stimulated Raman scattering effect, efficiently converting pump light energy into signal light and improving overall Raman gain and energy conversion efficiency. Simultaneously, it balances the stability of the amplification process with the integrity of the pulse waveform, thereby achieving a smooth, step-by-step amplification of the U-band pulsed seed light. Ultimately, it stably outputs high-energy U-band square-wave pulsed light with a single pulse energy ≥5μJ and a pulse width of 80–120ns, significantly improving the light source's output performance and better meeting the application requirements of long-distance fiber optic communication expansion and atmospheric methane remote sensing.

The invention relates to the technical field of optical fiber communication, and provides a third-order Raman amplification method, system and device. The pumping unit of the third-order Raman amplifier outputs the pumping light, and the signal emission unit outputs the signal light; the signal light passes through the transmission unit and then is combined with the pump light to obtain an output signal; the signal receiving unit collects signal power and OSNR data of the output signal and takes the signal power and the OSNR data as experimental reference data; training a PINN model by using system parameters to obtain an intermediate model; performing forward simulation and / or reverse parameter identification by using the intermediate model to obtain an output result; and comparing the output result with experimental reference data, when an error exceeds a preset threshold value, re-training the PINN model until a new error is less than or equal to the preset threshold value to obtain a target model, and completing forward simulation and / or reverse parameter identification by using the target model and the third-order Raman amplifier. The problems that an existing third-order Raman amplifier uses a traditional modeling method and is low in precision and poor in efficiency are solved.

The present invention discloses a Raman amplification system, which comprises: a pump source, which emits a Raman amplification signal with a wavelength of λ P The pump light is split into two beams by the spectrometer: one beam is used as the pump light of the Raman amplifier, which passes through the time delay device and the amplifier, and after the beam aperture adjustment and collimation of the first telescope device, passes through the first dichroic mirror at 45 degrees, and enters the Raman amplifier composed of the first Raman crystal, the first plane mirror, and the second plane mirror; the other beam is reflected by the third plane mirror and injected into the Raman oscillator to generate a wavelength of λ S The Stokes light of the Raman oscillator is composed of a fourth plane reflector, a second Raman crystal, and a concave reflector; the wavelength is λ S The Stokes light is adjusted and collimated by the second telescope device, reflected by the 45° second dichroic mirror and the first dichroic mirror, and then enters the Raman amplifier.

The present application relates to a kind of method and device for calculating the nonlinear noise of Raman amplification scene.The method part mainly includes: obtaining the equivalent in-fiber optical power spectrum of each channel according to Raman coupling equation or obtaining the equivalent in-fiber optical power spectrum of each channel according to Raman analytical equation;According to the equivalent in-fiber optical power spectrum of each channel and related fiber parameters, the equivalent nonlinear noise signal ratio of each channel is obtained by calculation, and the equivalent signal noise ratio caused by nonlinearity in Raman amplification scene is finally obtained.The present application can solve the problem that traditional model is too complex and backward Raman amplification scene is difficult to solve, and is more practical.

This invention belongs to the field of optical fiber testing and sensing technology, specifically relating to a method for identifying faults and disturbances in few-mode optical fibers using Raman-enhanced time-domain reflectometry (TDDR). The method includes: signal transmission based on pulse coding and mode-selective excitation; signal-to-noise ratio enhancement based on distributed Raman amplification; mode demultiplexing and mode field detection; coded demodulation and reconstruction using a multi-mode few-mode optical TDDR; multi-dimensional fault identification based on mode-dependent loss and coupling characteristics; and multi-mode differential and high-precision positioning based on digital signal processing. This invention targets high-capacity communication and distributed sensing systems using few-mode fibers. It solves the problem of detecting weak inter-mode scattering signals by coordinating pulse coding gain and distributed Raman optical gain. Subsequently, it utilizes the unique mode-dependent loss and inter-mode energy transfer characteristics of few-mode fibers for joint decision-making, providing highly sensitive, multi-dimensional optical fiber link health monitoring capabilities. This method has great potential and application prospects in the operation and maintenance of next-generation space-multiplexed optical networks.

A device, system, and method for distributed Raman amplification of a multi-core fiber (MCF) is disclosed. The optical amplifier device includes a plurality of single mode optical pumps configured to supply one or more wavelengths to a depolarizer and a mode multiplexer configured to receive the one or more wavelengths from the depolarizer to output at least one combined depolarized optical light comprising the one or more wavelengths. The device also includes a coupler to couple the at least one combined depolarized optical light into MCF. The combined depolarized optical light Raman amplifies an optical signal in the MCF.

An optical transmission apparatus is disposed at an end of a single-core optical fiber and is used when signal light is transmitted bidirectionally by the optical fiber. The optical transmission apparatus includes an optical transmitter that transmits a first signal light in one direction belonging to the signal light, an optical receiver that receives a second signal light in an opposite direction belonging to the signal light, an optical circulator that guides the first signal light transmitted from the optical transmitter to the optical fiber and guides the second signal light from the optical fiber to the optical receiver, and a light source that outputs, to the optical fiber, pump light for Raman-amplifying the second signal light to a second optical power higher than a first optical power of the first signal light.

An analysis device according to the present invention analyzes a power profile for signal light from an optical transmission system that uses distributed Raman amplification from backward excitation light. The analysis device comprises an input unit that receives input of information that indicates signal conditions, the characteristics of an optical fiber transmission path, and conditions for Raman excitation light, an amplification characteristics analysis unit that calculates the power profile using the information inputted to the input unit to perform iterative calculation of a coupling equation and performs analysis of distributed Raman amplification characteristics, and an output unit that outputs information that indicates the distributed Raman amplification characteristics analyzed by the amplification characteristics analysis unit. The amplification characteristics analysis unit comprises a first analysis unit that performs first analysis processing that causes convergence to an approximate power profile while avoiding divergence and a second analysis unit that performs second analysis processing that causes convergence to a more accurate power profile using an update formula based on a perturbation approach. The first analysis processing causes convergence to the approximate power profile by analysis of the coupling equation for the reverse direction of only the backward excitation light.

The invention discloses a phi-OTDR and BOTDR fused ultra-long-distance multi-parameter sensing system and a working method thereof, relates to the technical field of optical fiber measurement, and is used for solving the problem of simultaneous measurement of multiple parameters in long-distance sensing. The system comprises a narrow linewidth light source, an optical fiber coupler, an acoustic optical modulator, a semiconductor optical amplifier, a random scrambler, a Raman laser, a circulator, a polarization beam splitter, a delay optical fiber, a wavelength division multiplexer, an erbium-doped optical fiber, a signal generator, an electro-optical modulator, a microwave generator, a fiber bragg grating, a photoelectric balance detector, a data acquisition card and the like. According to the invention, the phi-OTDR and the BOTDR of a coherent detection structure are fused, the extinction ratio of detection pulse light is improved through modulator cascade connection, and simultaneous measurement of ultra-long-distance temperature, strain and vibration parameters is realized under the assistance of bidirectional Raman amplification and remote pump amplification technologies; the system is high in fusion degree, low in cost and high in practicability, and has important application significance in the monitoring fields of ultra-long distance invasion, pipeline leakage, high-voltage transmission lines and the like.

Embodiments of the present disclosure show an optical system, with a dual-ended laser apparatus, that comprises a laser light source coupled to a controllable current drive. The dual-ended laser apparatus outputs a first light beam and a second light beam generated by the laser light source. A wavelength locker is coupled to one of the light beams, and controls the output wavelength via optical feedback signal. The system may be used to pump a fiber Raman amplifier.

The invention discloses a large-energy stimulated Raman laser based on a batten structure, and belongs to the technical field of laser technology and nonlinear optics. The laser comprises a pumping source, a shaping optical system, a slab laser crystal, a Q-switching device, a resonant cavity and an amplification structure. According to the laser, a lath-shaped gain medium and a Raman crystal are adopted, and high-efficiency 1 [mu] m pulse laser output is realized through partial end face pumping and a polarization two-way amplification technology; the external cavity type Raman resonant cavity is further utilized to generate stable stimulated Raman seed light, and a light path is regulated and controlled through multiple reflectors, so that the seed light and the pump light are in time-space synchronization in the lath Raman amplification crystal, and efficient stimulated Raman amplification is realized. The problems that a traditional rod-shaped structure is poor in heat dissipation and remarkable in heat effect are effectively solved, and the device has the advantages of being high in heat dissipation efficiency, good in light beam quality, large in output energy and high in stability and is suitable for the fields of atmosphere laser radar detection, photoelectric countermeasure, spectrum detection, medical treatment, industrial processing and the like.

An object of the present invention is to provide an optical transmission system capable of satisfying XT required by a modulation system even if there is an inter-core loss difference in an MCF.An optical transmission system of the present invention includes a multi-core optical fiber having a plurality of core regions and having different losses between at least two cores, a forward excitation light source and a multiplexing unit for allowing Raman amplification excitation light to be incident on each core of the multi-core optical fiber in the same direction as signal light, and a backward excitation light source and a multiplexing unit for allowing Raman amplification excitation light to be incident on each core of the multi-core optical fiber in a direction opposite to the signal light, wherein an intensity ratio of the forward excitation light to the backward excitation light is controlled (a ratio of power of excitation light is set to a predetermined value) such that crosstalk (XT) fluctuation between cores is reduced.

The application discloses a kind of big energy stimulated raman laser based on batten structure, belong to laser technology and nonlinear optics field.The laser includes pump source, shaping optical system, batten laser crystal, Q device, resonant cavity and amplification structure.The laser uses batten gain medium and raman crystal, realizes high-efficiency 1 μm pulse laser output by partial end face pumping and polarization double-pass amplification technology;Further utilize external cavity raman resonant cavity to generate stable stimulated raman seed light, and pass through multi-mirror regulation light path, so that seed light and pump light are in batten raman amplification crystal space synchronization, realize high-efficiency stimulated raman amplification.The application effectively solves the problem of poor heat dissipation and significant thermal effect of traditional rod structure, has the advantages of high heat dissipation efficiency, good beam quality, large output energy, strong stability, is suitable for atmospheric laser radar detection, photoelectric countermeasure, spectrum detection, medical treatment and industrial processing and other fields.

An optical signal amplification apparatus includes a power detection module, a pump control module, and a Raman amplification module. The power detection module is configured to detect power of each of a plurality of G wavelength channels in each of a plurality of N spatial dimensions, and send power configuration information to the pump control module. The pump control module is configured to output N channels of pump light, where each channel of pump light includes M pieces of split pump light of different wavelengths, and a proportion of each piece of split pump light in pump light of a corresponding wavelength is determined based on the power configuration information. The Raman amplification module is configured to perform Raman amplification on a space division multiplexed signal in all of the N spatial dimensions by using the N channels of pump light.

A fiber optic Raman amplifier system includes a Raman pump module having a first pump laser at a first wavelength and a first power and a second pump laser at a second wavelength and a second power. The difference between the second wavelength and the first wavelength is less than 10 nanometers. A ratio of the first power to the second power is adjusted to establish a Raman gain in a bandwidth.