50 results about "Four-wave mixing" patented technology

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.

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.

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.

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 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 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.

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 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.

The invention is suitable for the technical field of all-optical signal processing, and provides an all-optical signal processing method and system based on an optical fiber nonlinear effect, and the method comprises the steps: receiving optical signals, and carrying out the coupling of the optical signals; the method comprises the following steps of: performing resonance enhancement on an optical signal by utilizing a resonant cavity, outputting an enhanced pump light signal, calculating conversion light generation efficiency by utilizing a coupling mode theory and a four-wave mixing theory, inputting the conversion light generation efficiency into a big database for matching, and outputting information of successful or failed enhancement of the optical signal. The all-optical signal processing function and the larger broadband are achieved through the nonlinear effect, the enhanced optical signal is automatically judged, and therefore whether the optical signal is successfully enhanced or not can be automatically recognized, and the problems that the optical signal processing effect is poor, and whether processing is successful or not cannot be automatically recognized are solved.

The present application belongs to the field of communication technology, and particularly relates to a kind of on-chip ultra-wideband white noise generation method based on chaotic micro-ring optical frequency comb, the implementation of the method includes semiconductor laser, micro-ring resonator, photodetector, characterized by: semiconductor laser, micro-ring resonator, photodetector 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, after being output through micro-ring resonator straight-through end, equal-interval chaotic optical frequency comb is generated, and then through the beat of multiple chaotic optical frequency comb, high-bandwidth noise signal can be realized.The present application compared with existing noise source, simple structure and has smaller volume, low power consumption, high stability and bandwidth expandable advantage.

Provided is a communication device that performs wavelength division multiplexing communication with a counterpart device that is a communication partner. The communication device comprises: a wavelength arrangement determination unit that determines a plurality of wavelengths to be used for communication with the counterpart device on the basis of a wavelength arrangement determined so as not to overlap a frequency position of idler light generated by four-wave mixing and an estimate value of the zero dispersion wavelength of a communication path connected to the counterpart device; a plurality of transmitters that transmit the light of the plurality of wavelengths determined by the wavelength arrangement determination unit; and a multiplexing unit that wavelength-multiplexes and outputs the light of the plurality of wavelengths outputted from each of the plurality of transmitters.　

Methodology of generation, with the use of a degenerate four-wave mixing nonlinear process, of ultrafast synthesized quantum light pulses with attosecond resolution (as demonstrated - at petaHertz and sub-petaHertz frequencies) and that exhibit amplitude squeezing. Demonstration of controllability and tunability of quantum uncertainty of light in real time via switching between amplitude and phase squeezing. Example of an attosecond quantum encryption protocol leveraging squeezed synthesized light for secure digital communication at petahertz-speeds.

A coherent anti-stokes Raman scattering apparatus for imaging a sample includes an optical output; an optical source arranged to generate a first optical signal at a first wavelength; and a nonlinear element arranged to receive the first optical signal, where the nonlinear element is arranged to cause the first optical signal to undergo four-wave mixing on transmission through the nonlinear element such that a second optical signal at a second wavelength and a third optical signal at a third wavelength are generated, wherein an optical signal pair including two of the first, second and third optical signals is provided to the optical output for imaging the sample.

The invention discloses an ultra-large-mode-field ultra-low-numerical-aperture high-damage-resistance controllable optical waveguide structure and a method for improving the quality of an ultra-strong and ultra-short pulse laser beam, and particularly aims to solve the problem that the beam quality is reduced when the power of ultra-strong and ultra-short pulse laser is developed to be higher. The optical waveguide structure comprises a temperature control device, a cladding and gas, and in specific application, the temperature control device and the cladding can be separated and can also be combined into an integrated structure, so that the compactness and the stability of a system are improved. Laser transmission is placed in a cladding filled with gas, and gradient refractive index distribution is formed by means of gas temperature gradient in the cladding. Based on a light beam self-cleaning process in the gradient refractive index waveguide, gradient refractive index distribution caused by a gas temperature gradient can effectively guide laser transmission, and the light beam quality is improved. And the output beam quality of the laser is further optimized through the nonlinear effect (such as intermode four-wave mixing) interaction of the laser during transmission in the gas medium. The ultra-large-mode-field ultra-low-numerical-aperture high-damage-resistance controllable optical waveguide structure can be widely applied to transmission and amplification systems of ultra-strong and ultra-short laser, and has potential application value.

Quantum state readout is achieved using four-wave mixing. A quantum-state carrier, e.g., a cesium 133 atom, is illuminated with a set of three wavelengths. In the event that the atom is in a first quantum state, e.g., an F=3 state of cesium 133, the illumination triggers emission in a first direction from the atom of a fourth wavelength due to four-wave mixing. Detection of the emission in the first direction thus indicates that the atom is in the first quantum state. In an embodiment, failure to detect an emission indicates the atom is in a second quantum state. In other embodiments, a second set of three wavelengths is used to provide a positive indication that the atom is in its second state, e.g., an F=4 state for cesium 133.

The invention particularly discloses an optical fiber endoscopic device and method for NADH and FAD synchronous two-photon imaging, and relates to the technical field of biological imaging. The device comprises a laser collimation and beam expansion module, a light beam switching module, a pulse chirp module, an endoscopic detection module and a fluorescence acquisition and processing module. Wherein the laser collimation and beam expansion module is used for carrying out collimation and beam expansion on spatial light emitted by a laser; the light beam switching module is used for alternately switching the double-color exciting light into the endoscopic system; the pulse chirp module compensates the broadening of the optical pulse transmitted by the optical fiber; the endoscopic detection module transmits exciting light to a sample and realizes light beam and fluorescence signal scanning; and the fluorescence acquisition and processing module separates and collects fluorescence signals of different wavebands and reconstructs an image. The device effectively solves the problems of instable excitation, four-wave mixing, incapability of dynamically regulating and controlling the time interval of double-color excitation light pulses and the like in the prior art, synchronous two-photon endoscopic imaging of NADH and FAD is realized, and the imaging quality and the system adaptability are improved.

The application discloses a fiber grating temperature control device, which comprises a plurality of supporting blocks arranged in a linear array on a mounting body, wherein the supporting blocks are respectively connected with temperature control modules and are provided with coaxial mounting grooves. In the application, the temperature control device is used to realize the temperature control of the individual supporting blocks through the temperature control modules connected with the supporting blocks, to adjust the expansion of the fiber grating at different positions through the multi-section temperature control high-precision, to actively introduce the time delay difference to suppress the nonlinear crosstalk (cross phase modulation and four-wave mixing effect), and to isolate the fiber grating and the temperature control module through the heat insulation blocks, that is, to isolate the heat convection and heat radiation of the fiber grating and the system environment, so that the temperature control speed and precision are greatly improved, the influence of the nonlinear crosstalk on the pulse shape is effectively suppressed, the adjustment cost is reduced, and the pulse quality and pulse stability are improved.

This invention discloses a six-sided three-dimensional optical storage and computing integrated chip and its storage and computing method, belonging to the field of chip technology. It includes a three-dimensional storage body formed by stacking and bonding nanocrystalline materials, optoelectronic fusion chips respectively attached to the six outer surfaces of the three-dimensional storage body, a laser writing module, and a laser reading module. The six optoelectronic fusion chips constitute three pairs of face-to-face optoelectronic fusion chips, including an information input optoelectronic fusion chip pair, an information output optoelectronic fusion chip pair, and a resource retrieval and computation optoelectronic fusion chip pair. The laser writing module controls the three pairs of face-to-face optoelectronic fusion chips to emit high-frequency, high-power laser beams, changing the crystal phase of the nanocrystalline materials inside the three-dimensional storage body. The laser reading module controls the three pairs of face-to-face optoelectronic fusion chips to emit low-frequency, low-power laser beams, generating a four-wave mixed signal light. This invention uses the above-mentioned chip and its storage and computing method, utilizing third-order nonlinear optical effects and four-wave mixing to achieve uniqueness determination of information writing and reading.