71 results about "Four-wave mixing" patented technology

The invention relates to the technical field of optical communication, in particular to a front optical fiber amplifier with a power balancing function. On the basis of a traditional Er-doped optical fiber amplifier, incident light is divided into a signal link and a competition link through a light splitting device with a fixed proportion. The purpose of introducing the competitive link is to generate a competitive wavelength which has an obvious competitive effect with the signal light in the EDF, and gain competition is carried out in the amplification process of the signal light in the EDF; wherein the competitive link finishes conversion from signal light wavelength to wavelength with obvious competitive effect by adopting a four-wave mixing principle based on HNLF, and then reversely inputs the converted competitive light into the EDF of the signal link to carry out a light amplification process with gain competition, so that the aim of reducing the output power fluctuation range after the signal light is amplified by the EDF is fulfilled.

The application discloses a bidirectional pumping quantum light source system, which comprises a multimode interference coupler, two asymmetric Mach-Zehnder interferometers AMZI1 and AMZI2 and a quantum light source. The input end of the multimode interference coupler is used for receiving pumping light. The first output end of the multimode interference coupler is connected with the input end of the AMZI1, and the first output end of the AMZI1 is connected with the first end of the quantum light source. The second output end of the multimode interference coupler is connected with the input end of the AMZI2, and the first output end of the AMZI2 is connected with the second end of the quantum light source, so as to form a Sagnac ring. The bidirectional pumping quantum light source system disclosed by the application utilizes the characteristics that the frequencies of pumping light and generated signal and idler photons are different in the spontaneous four-wave mixing process, embeds the asymmetric Mach-Zehnder interferometer with filtering effect into the Sagnac ring, and realizes the extraction of signal and idler photons in the Sagnac ring.

Various approaches can be used to interrogate a surface such as a surface of a layered semiconductor structure on a semiconductor wafer. Certain approaches employ Second Harmonic Generation while other utilize four wave-mixing or multi-wave mixing. Corona discharge may be applied to the sample to provide additional information. Some approaches involve determining current flow from a sample illuminated with radiation.

The present invention discloses a multimode four-wave mixing (FWM) automatic mode-locking device and method. The device comprises: a host computer, an electric polarization controller, a spatiotemporal mode-locked laser, an oscilloscope, and a spectrometer. The host computer is connected to the spatiotemporal mode-locked laser; the electric polarization controller is located within the spatiotemporal mode-locked laser; the inputs of the oscilloscope and spectrometer are connected to the spatiotemporal mode-locked laser, and the outputs of the oscilloscope and spectrometer are connected to the host computer. The host computer is configured to output a voltage to control the electric polarization controller, acquire data from the oscilloscope and spectrometer, and execute a FWM automatic mode-locking algorithm. The electric polarization controller receives a voltage signal from the host computer, regulates the polarization state and fiber length of the spatiotemporal mode-locked laser, and changes the energy coupling between different transverse modes within the spatiotemporal mode-locked laser. The present invention achieves automatic mode-locking of FWM by automatically detecting the FWM phenomenon.

Optical multiplexers, optical demultiplexers, optical transmitters including the optical multiplexers, optical modules including the optical transmitters and the optical demultiplexers, and methods of using the same are disclosed. The optical multiplexers include first and second beam combiners, a polarizing beam combiner, and an optical isolator. The first and second beam combiners each include a reflective surface and at least one filter, and are configured to combine individual optical signals having the same polarization state into a multi-channel polarized optical signal. However, the two separate multi-channel polarized optical signals having different polarization states. The polarizing beam combiner includes one or more reflective surfaces and one or more polarization filters, and is configured to combine the multi-channel polarized optical signals into a multi-channel output signal. The optical demultiplexers are structurally similar to the optical multiplexers, but provide a complementary or reverse function.The present multiplexers and demultiplexers reduce the four-wave mixing effect.

The invention provides a four-wave mixing suppression method and system for an IMDD optical fiber communication system, and the method comprises the steps: introducing two orthogonal bias terms which are gradually changed along with time into a judgment-guided equalizer, and tracking in-phase and orthogonal channel components of noise after orthogonal down-conversion, therefore, the narrow-band noise of the specified frequency band can be efficiently eliminated from the received signal; by monitoring the phase rotation direction and speed of a complex signal formed by the two offset terms, the frequency difference of the actual noise center frequency relative to the reference frequency can be directly calculated, so that the low-complexity adaptive tracking of the noise center frequency drift is realized. According to the invention, any center frequency narrow-band noise in a signal band can be efficiently suppressed and the center frequency change can be adapted without interrupting the service without a complicated spectrum analysis module, so that the signal quality is remarkably improved.

A degenerate four-wave mixing (DFWM) squeezed light apparatus includes one or more pump beams, a probe beam, a vapor cell, a repump beam, and a detector. The one or more pump beams includes an input power of no greater than about 150 mW. The vapor cell includes an atomic vapor configured to interact with overlapped pump and probe beams to generate an amplified probe beam and a conjugate beam. The repump beam is configured to optically pump the atomic vapor to a ground state and decrease atomic decoherence of the atomic vapor. The detector is configured to measure squeezing due to quantum correlations between the amplified probe beam and the conjugate beam. The one or more pump beams, the probe beam, and the repump beam are configured to generate two-mode squeezed light by DFWM with squeezing of at least 3 dB below shot noise.

The invention relates to a laser chaotic secret communication system based on coherent pumping phase conjugation, which belongs to the technical field of laser communication and comprises a signal transmitting module, an optical fiber link module, a conjugate transpose module and a signal receiving module. The signal transmitting module generates and modulates a chaotic carrier optical signal, and data encryption is realized through phase modulation; the optical fiber link module is used for long-distance signal transmission; the conjugate transpose module adopts an optical comb to generate coherent pump light, and generates phase conjugate waves through four-wave mixing to realize compensation of dispersion and nonlinear distortion in an optical fiber link; and the signal receiving module recovers original data through chaotic synchronization, coherent detection and digital signal processing. The phase locking characteristic of coherent pumping is utilized, the phase noise influence in a traditional pumping system is reduced, the stability of the system is improved, the anti-interference performance of chaotic secret communication and the transmission quality of the system are improved, and a feasible scheme is provided for achieving high-fidelity and high-safety long-distance optical communication.

The present invention discloses an optical interferometer and phase detection method based on quantum entanglement, comprising a dual-beam generation system, a hybrid interferometer, and a detection system, wherein the output end of the dual-beam generation system is respectively connected to the hybrid interferometer and the detection system, and the output end of the hybrid interferometer is connected to the detection system. The dual-beam generation system includes a first four-wave mixer amplifier, the input end of which is incident with coherent light and first vacuum light, and the output end of which generates a first conjugate beam and a first detection beam. The first conjugate beam enters the detection system, and the first detection beam and the second vacuum light are input into the second four-wave mixer amplifier of the hybrid interferometer to generate a second conjugate beam and a second detection beam. The above beams are combined to output a signal beam, which is connected to the detection system. The present invention has high detection efficiency, amplifies the total number of photons inside the interferometer, has low detection loss, and has a phase sensitivity that can break through the shot noise limit and approach the Heisenberg limit.

The present invention discloses a phase-correlated narrow-linewidth multi-wavelength single-frequency fiber laser based on four-wave mixing. The phase-correlated narrow-linewidth multi-wavelength single-frequency fiber laser is composed of a dual-wavelength single-frequency fiber laser seed source, a laser power amplifier, a nonlinear medium, and a filtering device. The dual-wavelength single-frequency fiber laser seed source is used to generate a dual-wavelength laser with high phase correlation; the laser power amplifier is used to amplify the power of the laser; the nonlinear medium is used to stimulate the four-wave mixing effect, thereby generating a multi-wavelength single-frequency fiber laser; and the filtering device is used to filter out a single wavelength of the multi-wavelength laser, the linewidth of which is measured and analyzed by a linewidth test system. The present invention has the characteristics of an all-fiber structure, a simple device, and strong resistance to environmental interference.

Systems and methods for generating an entangled pair of bichromatic photons are described. The system includes an atomic vapor cell containing atoms of an atomic species located within beam paths of a first and second laser beam. The first and second laser beams are tuned to first and second wavelengths that are resonant with first and second atomic transitions of the atomic species such that the first and second laser beams cause a four-wave mixing process within the atomic vapor cell. As a result of the four-wave mixing process, entangled photon pairs having a third and fourth wavelength are generated and output from the atomic vapor cell. The first and second wavelengths may be selected to create electromagnetically-induced transparency (EIT) within the atomic vapor cell, the EIT creating a transparent medium within the atomic vapor cell at the third wavelength, improving spectral brightness and / or photon linewidths.

Disclosed are an optical multiplexer (100, 100 ', 200, 200'), an optical demultiplexer, an optical transmitter comprising the optical multiplexer (100, 100 ', 200, 200'), an optical module comprising the optical transmitter and the optical demultiplexer, and methods of using the same. An optical multiplexer (100, 100 ', 200, 200') includes first and second beam combiners (110, 120), a polarized beam combiner (130), and an optical isolator (140). The first and second beam combiners (110, 120) each comprise a reflective surface and at least one optical filter for combining individual optical signals having the same polarization state into a multi-channel polarized optical signal. However, the two independent multi-channel polarized light signals have different polarization states. The polarized light beam combiner (130) comprises one or more reflecting surfaces and one or more polarization filters, and is used for combining the multi-channel polarized light signals into multi-channel output signals. The structure of the optical demultiplexer is similar to that of the optical multiplexer (100, 100 ', 200, 200'), but provides complementary or opposite functions. According to the multiplexer and the demultiplexer, the four-wave mixing effect is reduced.

The application relates to a waveguide loss measurement method based on double-channel detection, which is used for accurately obtaining the linear loss coefficient of a nonlinear waveguide to be measured. Pump light, probe light and auxiliary laser are combined and injected into the waveguide to be measured to trigger a four-wave mixing effect to generate idler light; then, the waveguide output light is split into two paths through a light splitting element, and the idler light signal and the auxiliary laser signal are extracted as a measurement channel and a reference channel; the waveguide temperature is adjusted to stabilize the idler light power, and a linear interval of the probe light and the idler light power is obtained through fitting; the probe light power is fixed in the interval, a noise compensation factor is generated by using the average power and the instantaneous power of the auxiliary laser, the idler light power is corrected in real time, and finally the waveguide loss is calculated based on the corrected data. The method realizes real-time noise cancellation through double channels, combines parameter locking and linear interval screening, greatly improves the measurement stability and precision, and adapts to the loss detection requirements of various nonlinear waveguides.

A method includes calculating a phase of a light pulse that is propagating along an optical fiber of a fiber broadband communications network, calculating a change in the phase of the light pulse due to a nonlinearity, determining a cause of a portion of the change in the phase, wherein the cause is at least one of: a self-phase modulation, a cross-phase modulation, or a four-wave mixing, and initiating at least one action to mitigate the nonlinearity, wherein the at least one action is selected based on the cause that is determined.

The invention discloses a three-resonance enhanced four-wave mixing VUV light source, which comprises a light splitting module, an optical parametric oscillation module and a mixing module, and is characterized in that the light splitting module utilizes a half-wave plate and a Glan prism to flexibly adjust to enter the Glan prism so as to divide incident light into two beams, and the two beams are respectively transmitted to the next Glan prism and the optical parametric oscillation module; the first half-wave plate is used for changing the polarization state of the incident light so as to adjust the light splitting ratio of the two beams of light; the optical parametric oscillation module comprises a first oscillation unit, a second oscillation unit and a third oscillation unit, and is used for performing a nonlinear process on the multiple beams of incident light split by the light splitting module so as to output multiple pieces of frequency mixing light with specific frequencies; and the frequency mixing module comprises a frequency mixing pool, the frequency mixing pool is filled with mercury vapor, the first frequency mixing light, the second frequency mixing light and the third frequency mixing light enter the frequency mixing pool through beam combination for four-wave mixing so as to obtain vacuum ultraviolet light, the adjustability is high, and the frequency mixing light energy output by each oscillation unit can be flexibly regulated and controlled.

The invention discloses a nonlinear effect and dispersion effect-based performance optimization method for an interferometer and [phi]-OTDR fusion system, and the method achieves the performance optimization of the interferometer and [phi]-OTDR fusion system through the nonlinear effect and dispersion effect generated by pulsed light and continuous light. According to the method, spectrum broadening of a detection signal is realized through pulse light self-phase modulation; frequency conversion is realized through four-wave mixing, and idler frequency light is generated; pulse compression is realized by using a continuous light group velocity dispersion effect, and pulse peak power is enhanced; the obtained pulsed light and continuous light are respectively demodulated to obtain high-fidelity and high-precision external disturbance information, so that the restrictive relationship between the spatial resolution and the sensing distance of the traditional phi-OTDR system is broken, and the spatial resolution and the signal-to-noise ratio of the fusion system are improved.

The present application belongs to the field of communication technology, and particularly relates to a kind of on-chip multi-path broadband white noise generation method based on chaotic micro-ring optical frequency comb, the implementation of the method includes semiconductor laser, micro-ring resonator, arrayed waveguide grating, photodetector, characterized by: the above-mentioned devices are integrated in the same chip substrate;Semiconductor laser output continuous light injection micro-ring resonator will occur four-wave mixing, self-phase modulation, cross-phase modulation and dispersion combined action, and equal-interval chaotic optical frequency comb is output through the straight-through end of micro-ring resonator.Coupling together after a plurality of micro-ring resonators generate chaotic optical frequency comb of different free spectral range, demultiplexing is carried out through arrayed waveguide grating, and finally multi-path broadband noise signal is output.Compared with existing noise source, the structure is simple, and has the advantages of low power consumption, high stability, bandwidth expansion, and solves the problem of lack of multi-path broadband noise signal implementation scheme, and can be applied to the field of secure communication, random number generation, etc.

The present invention belongs to the field of communications technology, specifically relating to a multi-channel broadband chaotic laser generator based on a microring resonator. The device comprises a distributed feedback semiconductor laser, a polarization controller, an adjustable optical attenuator, a microring resonator, a fiber optic reflector, and a wavelength division multiplexer. The device is characterized in that the distributed feedback semiconductor laser, polarization controller, adjustable optical attenuator, and the fiber optic reflector at the through-end of the microring resonator form a feedback loop to generate an initial chaotic laser. After the initial chaotic laser is injected into the microring resonator, it undergoes a combination of four-wave mixing, self-phase modulation, cross-phase modulation, and dispersion. After being output from the downstream end of the microring resonator, it generates a chaotic optical frequency comb with multiple comb teeth. Wavelength division multiplexing (WDM) technology can then be used to generate multi-channel, high-bandwidth chaotic signals. This invention addresses the lack of solutions for implementing multi-channel broadband chaotic lasers and can be applied to secure communications, radar ranging, random number generation, and other fields.

The present invention discloses a method for generating a tunable laser in the visible to deep ultraviolet band, comprising: providing a laser with a center frequency of ω p , wavelength is λ p The near-infrared ultrafast laser is used as the pump light source, and the pump light intensity exceeds the self-phase modulation threshold; the pump light is focused and incident on the nonlinear optical crystal to stimulate the self-phase modulation effect in the crystal, generating a center frequency of ω p The method involves adjusting the position or orientation of the nonlinear optical crystal so that the pump light and the broadened spectrum generated by self-phase modulation meet the phase matching conditions of four-wave mixing (FWM) in the NLO crystal, resulting in laser output from the visible to deep ultraviolet range. By continuously changing the phase matching conditions of the NLO crystal, the output laser frequency can be continuously tuned from the visible to deep ultraviolet range. This method overcomes the current problem of four-wave mixing technology that prevents wide-range frequency tuning of the output light and has potential applications in ultra-fine machining, UV lithography, air pollution monitoring, microsurgery, and other fields.

The invention relates to a laser communication transmitter system, a communication method, a lunar laser communication ground terminal, a communication system, a computer readable storage medium and a computer program product. The laser communication transmitter system comprises a transmitting unit and a free space light transmitting mirror; a hollow-core optical fiber jumper wire is adopted between the transmitting unit and the free space light transmitting mirror; and an optical signal generated by the transmitting unit is transmitted to the lunar laser communication satellite-borne terminal through a signal uplink via the hollow-core optical fiber patch cord and the free space light transmitting mirror. According to the mode, the laser communication transmitter system based on the hollow-core optical fiber patch cord is adopted, the influence of the nonlinear effect of the optical fiber on optical signals is remarkably reduced, and the quality and the stability of signal transmission are improved. By using the hollow-core optical fiber, spectral distortion caused by self-phase modulation and a four-wave mixing effect is effectively reduced, and the risk that beacon light is buried by noise is reduced, so that the signal detection and demodulation performance of a receiving end is improved.

An optical microscope contains a light source that emits coherent laser light with a wavelength of less than 550 nm; an optical system; and an electronic module. The microscope generates two copies of the laser light, modulates the phase or amplitude of the first copy relative to the second copy, and recombines the first and second copies to form an excitation beam. The microscope focuses the excitation beam onto a position on a material and measures a response beam from the material using an optical detector. The response beam contains transmitted and reflected light from the material. The microscope extracts a response signal from the response beam, which represents a nonlinear optical response of the material and indicates a property of the material. The optical detector is a semiconductor photodiode. The type of semiconductor photodiode is selected based on the photon energy of the laser beam.

Technologies for a photon pair source integrated on a photonic die are disclosed. In an illustrative embodiment, a photonic die includes an integrated semiconductor laser. The integrated semiconductor laser pumps a Raman laser on the same die. The Raman laser has much lower noise near the laser peak compared to the semiconductor laser, due to a smaller gain bandwidth and less amplified stimulated emission. Due to the low noise, the Raman laser can be used to pump a spontaneous four-wave mixing (SFWM) source directly, without off-chip filtering required. The SFWM source can generate entangled photons with a high signal-to-noise ratio, with applications for quantum cryptography, quantum computing, and other quantum information processing tasks.

The present invention relates to the technical field of photolithography machines, and in particular to a photolithography machine system and a photolithography method. The photolithography machine system includes a light source module capable of emitting at least two energy beams; an energy beam adjustment module for adjusting the wavelength and energy of the energy beam; an optical component module for collinearly combining and focusing the energy beams to form a Bessel beam; a four-wave mixing light emission module for providing four-wave mixing blue light, which can be collinearly combined and focused with the Bessel beam to form a short-wave energy beam; and a motion component module including a sample stage and an intelligent manipulator, wherein the sample stage is configured to be capable of position movement, and the intelligent manipulator is configured to adjust the position of a sample to be engraved on the sample stage. The system can achieve infinite reduction of the line width of the photolithography beam, and the beam can be reduced to 5nm, 3nm, 2nm, or even lower, thereby improving the photolithography accuracy while reducing power consumption.

A system and method are provided for generating entangled photon pairs containing two photons having different wavelengths. The technique involves pumping an atomic vapor of an alkali species using a pump laser and a coupled laser configured to drive a spontaneous four-wave mixing process within the atomic vapor. The pump laser and the coupled laser are detuned with respect to atomic transitions of the alkali species, thereby increasing the brightness of the entangled photon pair source.

The invention relates to a waveguide loss measurement method based on dual-channel detection, which is used for accurately acquiring a linear loss coefficient of a nonlinear waveguide to be measured. Firstly, pump light, probe light and auxiliary laser are combined and injected into a waveguide to be detected, and a four-wave mixing effect is triggered to generate idler frequency light; splitting the waveguide output light into two paths through a light splitting element, and extracting an idler frequency light signal and an auxiliary laser signal as a measurement channel and a reference channel; adjusting the waveguide temperature until the idle frequency optical power is stable, and fitting to obtain a linear interval between the probe light and the idle frequency optical power; and fixing the detection light power in the interval, generating a noise compensation factor by using the average power and the instantaneous power of the auxiliary laser, correcting the idle frequency light power in real time, and finally calculating the waveguide loss based on the corrected data. According to the method, real-time noise counteracting is achieved through two channels, parameter locking and linear interval screening are combined, the measurement stability and precision are greatly improved, and the loss detection requirements of various nonlinear waveguides are met.

The application provides an optical phase measurement method based on phase-sensitive non-Hermitian four-wave mixing, comprising generating a phase-sensitive non-Hermitian four-wave mixing process; detecting signal light and idler light emitted in the four-wave mixing process to obtain measurement results of a type-1 entanglement criterion and a type-2 entanglement criterion, and using the measurement results of the type-1 entanglement criterion and the type-2 entanglement criterion to realize measurement of an optical phase. The application uses a principle mechanism of the phase-sensitive non-Hermitian four-wave mixing process, and through non-Hermitian characteristics and optical phase sensitivity of the phase-sensitive non-Hermitian four-wave mixing process, measurement of a type-1 entanglement criterion is used to realize high-sensitivity optical phase measurement, and the application has the advantages of high robustness and higher sensitivity. The optical phase measurement method based on the phase-sensitive non-Hermitian four-wave mixing process has the advantage of high feasibility in realizing high-sensitivity optical phase measurement in combination with existing homodyne detection technology.

The invention provides a quantum light source generated by cross-band entangled photon pairs, and relates to the technical field of quantum information science, the quantum light source comprises a pump laser, a pump filter bank, a shallow ridge silicon waveguide and a signal / idle frequency filter bank, the pump filter bank is connected with the pump laser and the shallow ridge silicon waveguide, and the signal / idle frequency filter bank is connected with the shallow ridge silicon waveguide. The shallow ridge silicon waveguide is also connected with the signal / idle frequency filter bank; wherein the pump laser is used for generating narrow linewidth pump laser; the pumping filter group is used for carrying out band elimination filtering elimination on the narrow linewidth pumping laser to obtain target pumping laser; the shallow ridge silicon waveguide is used for exciting spontaneous four-wave mixing by target pumping laser to generate candidate entangled photon pairs; and the signal / idle frequency filter bank is used for receiving the candidate entangled photon pair and carrying out band-pass filtering processing to obtain a cross-band entangled photon pair comprising a target O-band photon and a target C-band photon. According to the technical scheme, the two photons of different wavebands in the entangled photon pair are generated based on the quantum light source, and the photon quality is improved.

The application discloses a kind of based on four-wave mixing effect's ultrafast laser output's fiber parametric oscillator, belong to laser technology and laser control field.It includes: pump source, wavelength division multiplexer, gain optical fiber, optical isolator, photonic crystal fiber, reflective wavelength division multiplexer, optical path delay line, 1×2 optical fiber coupler, data collector, optical fiber coupling photoelectric detector.The application utilizes passive optical fiber, gain optical fiber, photonic crystal fiber and optical fiber device not only realizes the full fiber of laser, but also improves the environmental stability of laser.Through reflective wavelength division multiplexer, 900nm signal light is filtered out and returned to ring cavity parametric oscillation, and through optical path delay line, the overlapping part of signal light and pump light is adjusted, finally through 1×2 optical fiber coupler, stable 900nm tunable ultrafast laser output is realized.

The invention relates to the technical field of laser spectrum measurement, in particular to a synchronous temperature and pressure measurement device based on a femtosecond laser-induced grating spectrum technology, which uses two beams of femtosecond laser pulses with the same pulse energy and polarization state to interfere with each other in a medium. The thermal grating is induced through rapid energy deposition, sound waves are generated on the cross section of the thermal grating, then a beam of continuous laser enters the thermal grating at a first-order Bragg diffraction angle, photon-phonon interaction is generated between the continuous laser and the sound waves, and therefore a beam of coherent scattered light is generated at a four-wave mixing phase matching angle; the femtosecond laser induces the grating to scatter the signal light. The signal light has a periodic oscillation structure in time, the signal intensity presents an exponential decay rule along with time, and the oscillation period and the decay time constant are respectively related to the sound wave propagation speed and the thermal diffusion rate, so that the dependency relationship between the measurement result and the gas state can be established; therefore, temperature and pressure information can be calculated by measuring femtosecond laser induced grating scattering signals.

Non-linear superconducting circuit for stabilizing at least one cat qubit, the non-linear superconducting circuit comprising: a four-wave mixing non-linear element (7); a first resonant portion (29); and a second resonant portion (31) which is coupled to the first resonant portion via the four-wave mixing non-linear element; wherein the first resonant portion, the second resonant portion, and the four-wave mixing non-linear element are configured together to provide a first physical oscillatory mode (a) with a first resonant frequency for hosting a cat qubit and a second physical oscillatory mode (b) with a second resonant frequency which is more dissipative than the first physical oscillatory mode (a); and wherein at least one of the first and second resonant portions comprises a tunable inductor (8) and a capacitor (43,39) such that at least one of the first and second resonant frequencies are tunable with the inductance of the tunable inductor.