36 results about "Raman gain" patented technology

The invention discloses a scanning high-resolution double-optical-comb spectrum system based on Raman gain modulation. The method is suitable for real-time spectrum detection with a wide spectrum range and high spectral resolution. The system comprises a single-frequency laser and driver, an optical coupler, a mode-locked laser, a rare earth doped amplifier, a wavelength division multiplexer, a Raman gain fiber, a sample to be tested, a photoelectric detector, a data processor and a wavemeter. The single-frequency laser couples part of light to the wavemeter, and the remaining light is divided into two paths to be coupled with the two amplified mode-locked lasers to enter the Raman gain optical fiber for Raman gain modulation and is converted into high-mutual-dryness double optical combs. The double combs pass through a to-be-measured sample in a combined manner, and interference signals are measured by the photoelectric detector and received by the data processor. And meanwhile, the processor sends a tuning signal to the single-frequency laser driver, so that the double combs scan in a wide spectrum range to obtain high-resolution spectrum information. Electrical feedback locking is not needed, and high-precision spectrum acquisition with megahertz resolution in a terahertz range can be completed within a few minutes.

The application discloses a self-adaptive Raman gain compensation system and method, and relates to the technical field of optical communication, wherein the self-adaptive Raman gain compensation system comprises: an optical fiber link; a Raman optical amplifier used for amplifying an input optical signal transmitted by the optical fiber link; a centralized optical amplifier used for amplifying an optical signal output by the Raman optical amplifier; and a compensation device used for acquiring and comparing partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier, and controlling the gain of the centralized optical amplifier based on a comparison result. The application can realize self-adaptive gain compensation when the gain of the Raman amplifier is insufficient.

A Raman fiber laser includes a pump light source, a reflective end mirror, a wavelength division multiplexer, a Raman gain fiber, and an output end mirror. The output end mirror is an ultra-low reflectance fiber Bragg grating. The reflective end mirror is connected to a reflective end of the wavelength division multiplexer. The pump light source is connected to an input end of the wavelength division multiplexer. One end of the Raman gain fiber is connected to a common end of the wavelength division multiplexer, and the other end of the Raman gain fiber is connected to the ultra-low reflectance fiber Bragg grating. The laser of the present invention can reduce loss of laser light at the reflective end mirror, thereby increasing laser light optical conversion efficiency and output power, and simultaneously achieving high time domain stability and extremely low coherence.

An optical arrangement for adjusting the wavelength of light, comprising: a first light source arranged to generate a first beam of light at a first wavelength; a second light source arranged to generate seed light at a second wavelength; a first Raman shifting medium arranged to receive the light from the first light source in combination with the seed light from the second light source, and to produce, by stimulated Raman scattering, output light at the second wavelength and having temporal properties determined by those of the first beam of light; a third light source arranged to generate seed light at a third wavelength; and a second Raman shifting medium arranged to receive the output light from the first Raman shifting medium in combination with the seed light from the third light source, and to produce, by stimulated Raman scattering, output light at the third wavelength and having temporal properties determined by those of the output light from the first Raman shifting medium; wherein the third wavelength is greater than the second wavelength, and the second wavelength is greater than the first wavelength; wherein the frequency difference between the first beam of light and the seed light from the second light source is a frequency difference where the first Raman shifting medium exhibits Raman gain; and wherein the frequency difference between the output light from the first Raman shifting medium and the seed light from the third light source is a frequency difference where the second Raman shifting medium exhibits Raman gain. Also provided is a corresponding method of adjusting the wavelength of light.

The application discloses a high-brightness and high-power Raman photonic crystal fiber laser, which comprises a pump source and a Raman gain medium connected with the pump source; the Raman gain medium is a full-solid photonic crystal fiber in a long cone shape; the full-solid long cone photonic crystal fiber is continuously and proportionally reduced in the whole cone area, and constantly satisfies the double-mode operation condition in the working wavelength range; the thick end is the input end, and the thin end is the output end; the full-solid photonic crystal fiber comprises a core and a cladding from inside to outside; the cladding microstructure comprises a high-refractive-index matrix material and a low-refractive-index filling material; the filling material is filled in the matrix material and is arranged in a two-dimensional closest equilateral triangle lattice periodically; the microstructure of the filling material is arranged in a concentric circle along the radial direction of the center of the core, and the number of the microstructure is 3-5 circles. The laser can effectively improve the laser beam quality of the output end and realize single-mode laser output.

The application discloses a high-power single-mode linear polarization Raman fiber laser based on a multimode optical fiber, and is characterized in that: a Raman gain medium of the laser is a single-clad circularly symmetric step-index distribution large-core multimode optical fiber; a base mode diameter of the step-index large-core multimode optical fiber is more than 65% of a core diameter; a Bragg fiber grating is inscribed in the core of the multimode optical fiber by using a femtosecond laser direct writing technology; a long axis of the grating region is coincided with a base mode field supported by the multimode optical fiber in a radial direction in space and length; the grating forms selective optical feedback only to the base mode in the cavity; a grating region with a difference between the long axis and the short axis forms selective feedback to one polarization state of the base mode; thus, the multimode optical fiber Raman laser effectively suppresses generation of mode instability at a high power level through active mode cleaning, and finally realizes near-diffraction-limited single-mode, high linear polarization and high-power Raman fiber laser output.

The application provides a Raman gain adaptive regulation method and system for a multi-band optical network, and the steps of the method comprise: supplementing gain values of non-target channels, constructing a gain vector based on target gain values of target channels and the supplemented gain values of the non-target channels, and performing at least one round of iteration; in each iteration, inputting values in a population into a pre-trained inverse model, the inverse model outputting corresponding pump adjustment parameters; determining gain values of all channels based on the pump adjustment parameters, screening target gain values of target channels from the gain values of all channels, and calculating fitness based on target gain values of target channels and the screened target gain values of the target channels; adjusting the supplemented gain values of non-target channels based on target function values, re-constructing the gain vector, and performing the next round of iteration, and after completing the last iteration, screening final pump adjustment parameters from all pump adjustment parameters.

The present invention discloses a wavelength-tunable Raman fiber laser based on gain control, comprising a second feedback component, a second coupling component, a gain component, a first coupling component, an output component, and a first feedback component, which are sequentially connected to form a linear cavity structure, and further comprising a second excitation component and a first excitation component. The light output by the first excitation component and the second excitation component has different central wavelengths. The present invention has a simple structure, wherein two pump lights of different central wavelengths are selected, each of which is power-amplified by an amplifying component and then coupled into a Raman gain fiber, i.e., a gain component. After the two Raman net gain spectra are superimposed on each other, Raman laser light can be emitted at the point of highest gain in the resonant cavity. Compared with traditional tunable Raman fiber lasers, there is no need for costly wavelength-tunable pump sources and tunable filters, and the resonant cavity structure is simple and compact with low loss.

The invention provides a narrow linewidth cascade Raman fiber laser system based on double-grating cooperative feedback, which comprises a pumping module, a Raman gain fiber and an N-order cascade Raman fiber resonant cavity structure, and is characterized in that the N-order cascade Raman fiber resonant cavity structure comprises N-order Raman fiber resonant cavities; wherein the first-order Raman optical fiber resonant cavity to the (N-1) th-order Raman optical fiber resonant cavity are all of asymmetric resonant cavity structures, and each of the first-order Raman optical fiber resonant cavity to the (N-1) th-order Raman optical fiber resonant cavity is composed of two corresponding-order Raman high-reflection gratings and a corresponding-order Raman low-reflection grating; the Nth-order Raman fiber resonant cavity is composed of an N-order Raman high-reflection grating and an N-order Raman low-reflection grating. According to the invention, through the double-Raman high-reflectivity grating in the asymmetric resonant cavity structure, the problem of line width broadening caused by mutual competition of multiple nonlinear effects during high-power operation of a cascaded Raman fiber laser system is solved, and narrow line width output under high power is realized.

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.

Systems and methods include receiving inputs comprising a Raman gain target for a Raman amplifier, fiber parameters, and fiber characteristics, each for an optical span; analyzing the inputs with a deep neural network (DNN) having a plurality of layers; providing a plurality of outputs from the DNN; and utilizing the plurality of outputs for a link budget calculation on the optical span. The Raman amplifier includes a plurality of pumps each at a fixed wavelength.

The invention relates to a device for inhibiting the influence of a light polarization state on a stimulated Raman signal, which is characterized in that a passive depolarizer device is added to a pump light branch of a stimulated Raman gas detection system to reduce the degree of polarization of pump light, so that the influence of the light polarization state change caused by the light path state change on a stimulated Raman gain signal is reduced. According to the device for inhibiting the influence of the light polarization state on the stimulated Raman gain signal, a passive depolarizer device is constructed by adopting a passive optical device and a single-mode optical fiber, and the passive depolarizer device comprises a first polarization controller, a first polarization beam splitter, a single-mode delay optical fiber, a second polarization controller and a second polarization beam splitter. According to the invention, the environmental adaptability of the gas sensing system based on the stimulated Raman effect in a real measurement scene is improved, and the practicability of the gas sensor is accelerated. The polarization degree of the pump light is reduced, meanwhile, the system cost is not obviously increased, and compared with an optical fiber scrambler and a passive depolarizer achieved through polarization maintaining optical fibers, the passive depolarizer has the obvious cost advantage.

The present invention provides an intracavity-pumped diamond mid-infrared Raman laser generating device and method. The device: a high-brightness laser pump source, a reflective laser beam expander-focusing device, a resonator input mirror, a laser gain medium, and a resonator output mirror are sequentially arranged at intervals to form a laser generating device. The method: according to the target laser wavelength, the optimal pump wavelength is calculated by the first-order and second-order Raman frequency shift formulas; according to the Raman gain relationship between the pump wavelength and the diamond crystal, the optimal values of the pump spot size, the mode field diameter of the Raman signal laser, and the diamond crystal length are designed; the resonator input mirror and the resonator output mirror are precisely adjusted to obtain the required Raman signal laser output; the switching of the output laser wavelength is achieved through the type of dielectric film of the resonator output mirror; continuous tunability of any wavelength from 2500 nm to 3780 nm of the output laser is realized. The device and method can achieve multi-wavelength output and can effectively output mid-infrared lasers in the 2 μm - 5 μm band.

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.

Systems and methods for clamping Raman gains are provided. According to one implementation, a method includes a step of limiting a gain of a Raman amplifier after maintenance or repair of a fiber span, where the Raman amplifier is configured to amplify optical signals propagating over the fiber span. The method also includes a step of obtaining local power measurements. Based on the local power measurements, the method includes a step of increasing the gain of the Raman amplifier. Furthermore, according to another implementation, an optical amplifier assembly may include a Raman amplifier configured to amplify optical signals propagating over a fiber span and a control device configured to limit a gain of the Raman amplifier after maintenance or repair of the fiber span.

The present invention discloses a method for generating a low-repetition-rate soliton microcomb for an aluminum nitride integrated optical microcavity. By using an aluminum nitride integrated optical microring resonator with a photonic crystal structure, the present invention translates the microcavity resonance peak near the stimulated Raman gain peak of aluminum nitride to reduce the effect of the stimulated Raman effect, rendering the competition between Raman gain and Kerr nonlinear gain ineffective, and enabling the generation of a soliton optical frequency comb in an aluminum nitride optical microcavity with a repetition rate less than 100 GHz. The present invention is a novel and effective method, which can enable the aluminum nitride microcavity to still generate a soliton-state optical microcomb at a low repetition rate less than 100 GHz, effectively solving the limitations in aspects such as waveguide design and fabrication when using an aluminum nitride optical microcavity to generate a soliton microcomb. The lower repetition rate can be compatible and adapted with existing mature electronic devices and equipment, and can be used in fields such as astronomical spectroscopy, microwave photonics, and dense integrated optical communication.

This invention provides a continuous U-band high-gain Raman fiber amplification module. It utilizes a Raman gain fiber with a dedicated gain peak at a 13 THz frequency shift, coupled with a broadband pump source with a 3 dB spectral width of at least 10 nm. A pump signal combiner is used to achieve efficient fusion coupling between the pump light and the U-band signal, ensuring that the broadband pump energy is precisely matched to the amplification requirements of the U-band signal. This achieves efficient high-gain amplification of the U-band signal, filling the amplification capability gap in this band of traditional amplifiers, ensuring the stability and efficiency of the amplification process, and ultimately outputting a high-purity, high-gain U-band laser signal. Compared with traditional Raman methods, this invention's Thraman fiber amplification module has advantages such as simple structure, high gain, and low cost, and has significant practical value and application prospects.

The invention provides a Raman fiber laser and an optical amplifier, and belongs to the technical field of optical communication. The Raman fiber laser comprises a plurality of pump light assemblies, a combiner, a multi-wavelength reflector, a Raman gain fiber and a multi-wavelength output device, each pump light assembly is connected with the combiner, the combiner is connected with the multi-wavelength reflector, and the Raman gain optical fiber is located between the multi-wavelength reflector and the multi-wavelength output device; the plurality of pump light assemblies are used for outputting optical signals with multiple wavelengths to the combiner; the combiner is used for combining the optical signals with multiple wavelengths into a combined signal and outputting the combined signal; the multi-wavelength reflector is used for inputting the combined wave signal to the Raman gain optical fiber and reflecting the middle Raman laser and the target Raman laser corresponding to each wavelength in multiple wavelengths; and the multi-wavelength output device is used for reflecting the middle Raman laser corresponding to each wavelength and outputting the target Raman laser corresponding to each wavelength. By adopting the Raman fiber laser, Raman laser with various wavelengths can be output.

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.

Systems and methods for measuring Raman gain in an optical span include, subsequent to determining a baseline measurement of a first total-power output at an upstream node and a first total-power input at a downstream node, causing a measurement a second total-power output at the upstream node and a second total-power input at the downstream node with one or more Raman pump lasers on; and determining a Raman gain for the optical span by comparing (a) a difference between the first total-power output and the first total-power input to (b) a difference between the second total-power output and the second total-power input. The baseline measurement was determined when one or more Raman pump lasers associated with the optical span were turned off. The Raman gain reflects an effective gain achieved over all of the optical span rather than only at a local amplifier input.

The present invention discloses a method and system for generating a Kerr soliton optical frequency comb based on adjustable Raman gain. The system comprises: a pump laser, a first polarization controller, a first optical amplifier, a first circulator, a control laser, a second polarization controller, a second optical amplifier, a second circulator, an optical microcavity, a first beam splitter, a spectrum analyzer, a second beam splitter, a fiber Bragg grating, a high-speed detector, a spectrum analyzer, a photodetector, and an oscilloscope. The present invention controls the gain and Q value of the Raman mode by controlling the laser, thereby increasing the power threshold for generating the Raman optical frequency comb and regulating the interaction between the two nonlinear effects of Kerr and Raman, thereby generating a Kerr soliton optical frequency comb with a high repetition rate, a wide spectrum, and a high degree of coherence.

The invention discloses a high-power and high-mutual dryness double-optical comb spectrum technology based on Raman gain modulation. The method can be used for rapid spectrum detection and multi-component atmosphere remote sensing. The system comprises a mode-locked laser, a rare earth doped optical fiber amplifier, a coupler, a Raman gain optical fiber, an optical splitter, a single-frequency laser, an acoustic optical modulator, a to-be-measured target, a photoelectric detector and sampling equipment. The two mode-locked lasers output ultrafast pulses, the ultrafast pulses are amplified through the rare earth doped optical fiber amplifiers respectively and coupled with the same single-frequency laser respectively to enter the Raman gain optical fiber, Raman gain modulation is provided for the single-frequency laser, the single-frequency laser is shaped into a high-power and high-mutual-dryness double-optical-frequency comb, and the double-optical-frequency comb is combined with the single-frequency laser. The repetition frequency is equal to the repetition frequency of the pump pulse. The two paths of output optical frequency combs have high mutual dryness and high output power, and high-speed and high-signal-to-noise-ratio double-optical-comb spectrum gas absorption detection is realized at the millisecond magnitude under the condition of no feedback locking and correction algorithm.

The invention discloses an on-chip stimulated Raman scattering gas sensing system and method, and particularly relates to the technical field of gas analysis and measurement. According to the system, pump light and Stokes light interact with gas to be detected in a sensing waveguide evanescent field area, the Raman scattering process of gas molecules is enhanced, and Stokes light Raman gain signals related to gas concentration are obtained. In order to suppress Raman background noise caused by a waveguide material, different polarization modes of Stokes light are introduced into a sensing waveguide, pump light is filtered out through a micro-ring resonator and a polarization beam splitter, and a TE fundamental mode and a TM fundamental mode of the Stokes light are separated; the balance photoelectric detector is used for carrying out differential processing on Raman gain signals corresponding to the two polarization modes, so that the signal-to-noise ratio and the sensitivity of gas detection are improved. And meanwhile, the laser, the sensing waveguide and the detection unit are integrated, so that the device has the advantages of compact structure, low power consumption and high sensitivity, and can realize ppm-magnitude gas detection.

The invention discloses a single-photon Raman temperature sensing system and a sensing method thereof, solves the problem of photon counting curve jittering caused by Raman gain in an optical fiber and polarization sensitivity of a single-photon detector, and belongs to the technical field of distributed optical fiber sensing and single-photon detection. According to the distributed optical fiber temperature sensing system and method based on the dual-wavelength cross-polarization pulse pumping, Raman pumping and single photon detection are carried out by combining a dual-independent-wavelength pulse light source with a cross-polarization synthesis light path; and photon number jitter of the Raman gain and the single-photon detector in the optical fiber due to the change of the polarization state of the optical signal can be effectively solved. According to the invention, the problem that the temperature measurement curve in the traditional single-photon Raman temperature sensing system changes periodically is eliminated, and the temperature measurement accuracy and the temperature resolution are higher, so that the method can be conveniently applied to the high-precision single-photon Raman temperature sensing system.

This invention discloses a method for improving the Raman gain coefficient of tellurate glass. By introducing Ga2O3 into a TeO2-BaF2-Y2O3 tellurate glass matrix, Ga ions enter the glass network and form [GaO4] tetrahedral structural units. These Ga ions then form a Te-O-Ga connection structure with the tellurium oxygen structural units through bridging oxygen bonds, thereby controlling the glass network structure and increasing the proportion of non-bridging oxygen. Raman spectroscopy results show that at 789 cm⁻¹... ‑1 The Te-O-Te vibration peak is enhanced at 480 cm⁻¹. ‑1 Vibrational characteristic peaks associated with the Te-O-Ga structure appear at a certain point. A peak intensity ratio evaluation function is constructed to quantitatively evaluate the glass structure, thereby obtaining tellurate glass materials with high Raman gain coefficients. Through structural tuning, the synergistic enhancement of the two main Raman vibrational modes can be achieved, thus significantly improving the Raman gain coefficient of tellurate glass.

The embodiment of the invention provides a hydrogen detection system and method and a storage medium, and belongs to the technical field of gas detection. The system comprises a pump laser, a Stokes laser, a polarization regulation and control module, an optical path coupling module, a distribution module, a detection module and a processing module. The polarization regulation and control module modulates the polarization state of first laser emitted by the pump laser, and the optical path coupling module couples the first laser modulated by the polarization regulation and control module and second laser emitted by the Stokes laser into third laser. The detection module is used for introducing hydrogen to be detected to generate stimulated Raman scattering with the third laser and outputting a current measurement signal; and the processing module is used for determining a current hydrogen concentration value according to the current measurement signal. A polarization regulation and control module is introduced into a pump light path, so that a polarization state quickly traverses a Poincare sphere within integral time, Raman gain equivalent to polarization average is obtained, and polarization state disturbance is eliminated. According to the invention, high-sensitivity and high-stability distributed trace hydrogen monitoring is realized.

To address the drawbacks of existing methods for measuring the Raman gain coefficient of optical fibers, such as their cumbersome complexity, this invention proposes a method, apparatus, device, and medium for predicting the Raman gain coefficient of the gain fiber in an optical fiber laser. The method includes inputting the phonon energy distribution, the number of phonons, and the phonon polarizability of the gain fiber in the optical fiber laser; constructing a Raman gain coefficient prediction model based on the phonon energy distribution; and inputting the phonon energy distribution, the number of phonons, and the phonon polarizability into the Raman gain coefficient prediction model to obtain the Raman gain coefficient of the gain fiber. This invention utilizes the magnitude of phonon energy in the gain fiber to rapidly predict the Raman gain coefficient in the optical fiber laser, thereby saving experimental time and significantly improving work efficiency.

The present invention relates to a tunable Raman fiber laser, wherein an output end of a pulse seed source unit is connected to a first beam splitter, one output end of the first beam splitter is connected to an input end of a first beam combiner, an output end of a first pump source is connected to the input end of the first beam combiner, an output end of the first beam combiner is connected to a first gain optical fiber, the first gain optical fiber is connected to an nth-order Raman gain optical fiber, and the nth-order Raman gain optical fiber is connected to an input end of a first isolator; the other output end of the first beam splitter is connected to an input end of a second beam combiner, an output end of a second pump source is connected to the input end of the second beam combiner, an output end of the second beam combiner is connected to a second gain optical fiber, the second gain optical fiber is connected to an (n-1)th-order Raman gain optical fiber, the (n-1)th-order Raman gain optical fiber is connected to an input end of a second isolator, and an output end of the first isolator and an output end of the second isolator are connected to an input end of an energy beam combiner; and an output end of the energy beam combiner is connected to a Raman gain optical fiber, and an output optical path of the Raman gain optical fiber is provided with a first filter. The pulse width and the wavelength can be adjusted.

The present invention relates to the technical field of communications, and provides a Raman amplifier gain control method and a Raman optical fiber amplifier. The method comprises: inputting pump light of a corresponding wavelength into an optical fiber, and measuring out-of-band ASE power of the optical fiber in each preset frequency band; determining an actual gain coefficient of each preset frequency band on the basis of the out-of-band ASE power of each preset frequency band; matching the actual gain coefficient of each preset frequency band with a preset Raman gain coefficient of each preset frequency band, using an optical fiber corresponding to an actual gain coefficient having the highest similarity obtained by means of matching as a first optical fiber, and using an adjustment parameter of the first optical fiber to perform gain control of a Raman amplifier. The present invention, by means of deriving a Raman gain coefficient in reverse by using the out-of-band ASE power, can measure the Raman gain coefficient during the working process of the Raman amplifier, resolving the problem of it being difficult for a distributed amplifier to acquire a gain coefficient of optical fiber.

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.