31 results about "Degenerate four wave mixing" patented technology

A regenerator for restoring the originally encoded optical phase of a differential-phase-shift-keyed signal. In an embodiment, the regenerator simultaneously provides limiting amplification and reduces amplitude noise based on a phase-sensitive optical amplifier that combines a weak signal field of a degraded input data with a strong pump field supplied by a local oscillator in a nonlinear interferometer. The two fields interact through degenerate four-wave mixing, and optical energy is transferred from the pump to the signal and vice versa. The phase sensitive nature of the optical gain leads to amplification of a specific phase component of the signal, determined by the input pump-signal phase difference and the incident signal phase is restored to two distinct states, separated by 180° according to the original encoding. Simultaneously, gain saturation of the pump wave by the signal wave results in limiting amplification of the signal wave for removing signal amplitude noise.

A system and method of remotely extracting information from a communications station by interrogation with a low power beam. Nonlinear phase conjugation of the low power beam results in a high power encoded return beam that automatically tracks the input beam and is corrected for atmospheric distortion. Intracavity nondegenerate four wave mixing is used in a broad area semiconductor laser in the communications station to produce the return beam.

A non-linear optical device is provided. The device comprises an optical disk or ring microresonator fabricated from a material that exhibits an optical nonlinearity able to produce degenerate four-wave mixing (FWM) in response to a pump beam having a pump frequency in a specified effective range. The microresonator is conformed to exhibit an angular group velocity minimum at a pump frequency within the specified effective range such that there is zero angular group velocity dispersion at the pump frequency. We refer to such a pump frequency as the “zero dispersion frequency”. In embodiments, excitation of the resonator by a pump beam of sufficient intensity at the zero-dispersion frequency causes the resonator to emit a frequency comb of entangled photon pairs wherein the respective frequencies in each pair are symmetrically placed about the zero-dispersion frequency.

The invention relates to an optical parametric oscillator, which comprises a nonlinear optical material (1) with the double-zero dispersion wavelength, a high reflector (2), an output mirror (3), a parametric oscillation optical beam collimator (4), a parametric optical line width compressor (5), a pumped optical coupler (6), a lambda / 2 phase retarder (7), a laser power controller (8) and an optical isolator (9). The nonlinear optical material (1) has a double-zero dispersion wavelength and is arranged in a resonant cavity formed by the high reflector and the output mirror. The pumped optical wavelength is in the anomalous dispersion regime of the photonic crystal fiber, thereby ensuring the phase matching conditions and generating the highly efficient four-wave mixing effect. For the parametric oscillation formed by simplifying the four-wave mixing, the wavelengths of the two parametric lights are respectively arranged at the double-zero dispersion wavelength of the photonic crystal optical fiber, thereby realizing the group velocity dispersion compensation of the parametric light, solving the problem of the ultra-short pulse dispersion compensation, and greatly reducing the pumping threshold.

The invention discloses a DFWM (Degenerate Four-Wave Mixing) spectroscopic technology based method for determining the date of cultural relics, which comprises the following steps of: dividing a laser beam by a beam splitting device into three beams to be incident into a sample to be determined; receiving a generated DFWM signal by a photoelectric detector; measuring the intensity of the DFWM signal to judge the content information of 14C; and reckoning the date of the cultural relics based on the decay theory of the 14C according to the content information of the 14C. The invention has the advantages of simple device, easy and feasible operation, and capability of eliminating Doppler widening and can overcome the deficiencies of poor dating precision, high sampling amount, complicated device, high operation difficulty, high cost and the like in the traditional isotope-dating technology.

A system, method, and apparatus for delayed optical logic gates based on slow light and enhanced nondegenerate four-wave mixing processes, where a single or multiple delayed optical routers are utilized for dark resonance interactions in which two-color lasers interact with a three-level nonlinear optical medium comprised of two ground states and one excited state through the nondegenerate four-wave mixing processes. The delayed optical logic mechanism is based on combination of single or multiple dark resonance-induced two-photon coherence conversion via slow light phenomenon. The two-photon coherence induced on the ground states is optically detected via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to dark resonance or electromagnetically induced transparency. The gating time and bandwidth of the present delayed optical logic gates is invariant to the delayed time of the delayed optical router because IN and OUT bandwidth across the nonlinear medium must be same. The present invention of delayed optical logic gates have potential to keep up ultra-high-bandwidth optical information processing using relatively slow electronic processing devices.

A semiconductor laser, such as surface emitting laser, is disclosed. According to one embodiment, the laser includes a first reflector assembly having an upper face, a second reflector assembly having a lower face that faces the upper face of the first reflector assembly, and a phase conjugator between the first and second reflector assemblies. The phase conjugator includes a first semiconductor active region parallel to the upper face of the first reflector assembly and the lower face of the second reflector assembly, a second semiconductor active region that is not parallel to first semiconductor active region, and a third semiconductor active region that is not parallel to the first semiconductor active region.

The invention provides a method for achieving all-optical quantum random number generation through the four-wave mixing effect. Two beams of pulse light with different wavelengths and continuous light pass through a highly nonlinear optical fiber, generate the degenerate four-wave mixing effect in the highly nonlinear optical fiber, and generate signal light with the phase having quantum randomness. The generated signal light is divided into two paths with equal intensity, one path of light interferes with the other path of light after delay, the intensity of output signals randomly occurs in the '0' state and in the '1' state, and accordingly quantization-free all-optical high-speed quantum random codes are obtained in real time. Devices used in the method include a mode-locked pulse laser device, a narrow-line-width laser device, the highly nonlinear optical fiber, a filter, a light delay line and an optical fiber coupler. The center wavelength of the mode-locked pulse laser device is not equal to that of the narrow-line-width laser device. The method for generating random numbers is conducted completely in an optical domain, can break through the electronic bottleneck limitation, does not need the light quantization technology, and is capable of generating the all-optical high-speed quantum random codes in real time.

A system, method, and apparatus for delayed optical router based on slow light and nondegenerate four-wave mixing processes are presented, in which three laser pulses interact with a three-level nonlinear optical medium composing two closely spaced ground states and an excited state. The delayed optical routing mechanism is based on a slow light phenomenon, in which a group velocity of an incoming input signal pulse is slowed down due to quantum coherence induced refractive index change. The two-photon coherence induced on the ground states via electromagnetically induced transparency is optically recovered via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to absorption cancellation. In this case, the individual pulse switching / routing time is limited by the coherence decay time that is much faster than population decay time, where the population decay-time is a limiting factor of conventional switching devices. In the present invention of the delayed optical router the overall switching / routing time, however, is controlled to be delayed by using the slow light. Even though the overall switching / routing time can be delayed, the switching bandwidth of the present invention is not degraded at all because the input and output signal's group velocity across the delayed optical router is still same. Therefore, the present invention of the delayed optical router gives an advantage of wide-bandwidth optical data traffic control using a narrow-bandwidth processing unit such as an electronic device. Another advantage is signal amplifications owing to the dark-resonance enhanced nondegenerate four-wave mixing processes.

The invention discloses a photonic crystal fiber based medium-infrared optical fiber parametric oscillator for degenerating four-wave mixing and relates to a laser oscillator. The photonic crystal fiber based medium-infrared optical fiber parametric oscillator is provided with a laser pumping source, a focusing lens system, four reflectors and a photonic crystal fiber which are sequentially serially connected to an optical fiber annular cavity, the laser pumping source is coupled to enter the photonic crystal fiber through the focusing lens system, oscillation and lasing of signal light in a visible light wave band are guaranteed by the four reflectors, and coherent medium-infrared idle-frequency light is outputted from the tail end of the photonic crystal fiber. Pumping laser with the wave range of 1030-1070nm is coupled to the photonic crystal fiber to stimulate nonlinear effect of the optical fiber four-wave mixing so as to achieve output of the laser in the medium-infrared wave band. The four reflectors in a resonant cavity structure of the oscillator are used to guarantee that the signal light in the visible light wave band is completely reflected in the cavity, and coherent medium-infrared idle-frequency light is completely outputted from the tail end of the photonic crystal fiber so that conversion efficiency is high.

The invention discloses a non-linear interferometer based on optical parameter process. The non-linear interferometer comprises a laser, a first half-wave plate, a second half-wave plate, a third half-wave plate, a first polarized beam splitter, a second polarized beam splitter, an acousto-optic modulation device, a first glan-laser polarizer, a second glan-laser polarizer, a first rubidium pool and a second rubidium pool.Pump light outputted by the laser is transformed to be probe light, second vertical polarised light and third vertical polarised light. The light and the second vertical polarised light are subjectd to four-wave mixing in the first rubidium pool in order to form first probe light and first conjugate light. The second vertical polarised light, the first probe light and the first conjugate light are subjected to four-wave mixing in the center of the second rubidium pool for outputting the first probe light and second conjugate light. The non-linear interferometer based on optical parameter process has following beneficial effects: nondegenerate four-wave mixing process of the nondegenerate four-wave mixing is utilized to generate a beam splitter and a beam-combining device replacing a conventional interferometer and the comparison ratio of interference fringes can be up to 99% around.

A system, method, and apparatus for delayed optical router based on slow light and nondegenerate four-wave mixing processes are presented, in which three laser pulses interact with a three-level nonlinear optical medium composing two closely spaced ground states and an excited state. The delayed optical routing mechanism is based on a slow light phenomenon, in which a group velocity of an incoming input signal pulse is slowed down due to quantum coherence induced refractive index change. The two-photon coherence induced on the ground states via electromagnetically induced transparency is optically recovered via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to absorption cancellation. In this case, the individual pulse switching / routing time is limited by the coherence decay time that is much faster than population decay time, where the population decay-time is a limiting factor of conventional switching devices. In the present invention of the delayed optical router the overall switching / routing time, however, is controlled to be delayed by using the slow light. Even though the overall switching / routing time can be delayed, the switching bandwidth of the present invention is not degraded at all because the input and output signal's group velocity across the delayed optical router is still same. Therefore, the present invention of the delayed optical router gives an advantage of wide-bandwidth optical data traffic control using a narrow-bandwidth processing unit such as an electronic device. Another advantage is signal amplifications owing to the dark-resonance enhanced nondegenerate four-wave mixing processes.

The invention discloses an FDFWM (forward degenerate four-wave mixing) based isotope detection method with an ultrahigh sensitivity. The method comprises the following steps: a laser beam is divided into three light beams with a same light path; space positions of the three light beams are adjusted; the three light beams are focused and interacted with an isotope sample to be detected on a focusing point to generate an FDFWM signal; a center frequency of a laser is scanned, and a photoelectric detector is employed to measure the FDFWM signal of the isotope sample to be detected, so as to obtain an FDFWM signal spectrum, which changes with the laser center frequency, of the FDFWM signal; and content information of the isotope sample to be detected is obtained according to the FDFWM signal spectrum. The method of the invention can increase a sensitivity of an isotope detection and realize near nondestructive test; if the method of the invention is employed to detect an isotope, a detection limit is lowered, and a sampling amount is reduced; besides, the method has advantages of relative simple equipment, convenient operation, and ultrahigh sensitivity and detection precision.

The invention discloses a configurable optical signal all-optical edge detection system. The system comprises a first erbium-doped fiber amplifier which is used for amplifying the power of a pump optical signal, a tunable optical attenuator which is used for adjusting the power of the pump optical signal after power amplifying, a first fiber delay line and a second fiber delay line. The first andsecond fiber delay lines are used for adjusting the relative delay amount of the pump optical signal and a first phase-reversed optical signal, and advancing or delaying the propagation time of the pump optical signal relative to the first phase-reversed optical signal by tau, wherein tau is the transit time of an NRZ optical signal. The system further comprises a wavelength division multiplexer which is used for coupling the pump optical signal and the first phase-reversed optical signal into an optical signal, a highly nonlinear optical fiber which is used for generating a degenerate four-wave mixing nonlinear effect under the action of the coupled optical signal to acquire a first idler light, and a first optical band-pass filter which is used for extracting the first idler light to acquire a first edge pulse. According to the invention, the principle of four-wave mixing is used; delay is introduced between two signals; and a rising edge, a falling edge or double edges can be flexibly acquired.

The invention discloses a phase-sensitive optical parameter amplifier and an operation method thereof. The wave numbers of three light beams, including received signal light, first pump light and second pump light meet a vector triangle relationship, wherein the first pump light and the second pump light are emitted from a local laser source; three beams of light are accessed into a three-order nonlinear medium device to generate a degeneracy four-wave mixing effect; the light beam emitted from the three-order nonlinear medium device is accessed into a polarization controller to control polarization components in X and Y directions to be converted to form an angle of 45 degrees with a polarized light beam splitter; polarized light in the X and Y directions of the polarized light beam splitter are reflected by a reflecting mirror group for multiple times to enter the polarized light beam splitter to be subjected to beam combination; and after combined beam light passes through an optical filter to serve as the output of the amplifier. By use of the amplifier, the signal light of which the power is smaller than pump light for more than two orders of magnitude is effectively amplified, signal phase noise is inhibited, and no amplitude noise is introduced. The amplifier has the advantages of simple structure, low cost and small volume, and is easy in popularization and use.

A system, method, and apparatus for photon logic gates based on quantum switch, where a single or multiple quantum switches are utilized for dark resonance interactions in which three-color lasers interact with a four-level or five-level nonlinear optical medium composed of three ground states and one or two excited states through nondegenerate four-wave mixing processes. The photon logic mechanism is based on combination of single or multiple dark resonance-induced two-photon coherence swapping among the three closely spaced ground states through optical transitions via a common excited state. The two-photon coherence induced on the ground states is optically detected via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to dark resonance or electromagnetically induced transparency. The gating time and bandwidth of the present photon logic gate method is not limited by population relaxation time or carrier's lifetime, but phase decay time, where the phase decay time in general much faster than the population decay time in solids or semiconductors.

The invention discloses a polarization insensitive high-frequency-multiplication optical millimeter wave generation simplification device and method belonging to the field of optical millimeter wave generation in a ROF (Radio Over Fiber) communication system technology. According to the invention, a double-arm lithium niobate and mach-zehnder modulator is adopted, and by setting proper bias voltage, modulation depth and a phase difference between radio frequency signals and combining a band-pass filter, plus and minus 3 order sidebands which are the same in polarization direction and locked inphase are generated; then a data baseband signal is loaded to the minus 3 order sideband by a single-arm mach-zehnder modulator, and after the minus 3 order sideband loaded with the data and the plus3 order sideband are coupled, the obtained product is fed into a SOA (Semiconductor Optical Amplifier) to implement degenerate four-wave mixing; and finally, plus and minus 9 order sidebands are filtered out by utilizing an optical cross multiplexer and is fed into a photoelectric detector to be subjected to frequency beating to obtain a 18-frequency-multiplication electric millimeter wave. According to the invention, the high-frequency-multiplication high-stability optical millimeter wave can be generated with low cost; and the device and the method are simple in structure and easy to implement.

A system, method, and apparatus for photon logic gates based on quantum switch, where a single or multiple quantum switches are utilized for dark resonance interactions in which three-color lasers interact with a four-level or five-level nonlinear optical medium composed of three ground states and one or two excited states through nondegenerate four-wave mixing processes. The photon logic mechanism is based on combination of single or multiple dark resonance-induced two-photon coherence swapping among the three closely spaced ground states through optical transitions via a common excited state. The two-photon coherence induced on the ground states is optically detected via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to dark resonance or electromagnetically induced transparency. The gating time and bandwidth of the present photon logic gate method is not limited by population relaxation time or carrier's lifetime, but phase decay time, where the phase decay time in general much faster than the population decay time in solids or semiconductors.

The invention provides a design method and a device for a two-dimensional body holographic grating solid-state laser. The main steps of the design method are to construct oscillating laser double-passsurface liquid-cooled semiconductor side-pumped slab module, including laser medium, pumping source and auxiliary glass sheet. A laser medium is arranged in a liquid cool cavity formed by an auxiliary glass sheet; The auxiliary glass sheet in the light passing direction has a small inclination angle with the laser medium. Using a low doping concentration laser medium; Saturation pumping on the side of laser medium; The influence of the side pump on the laser medium is represented by the equivalent opening angle of the water plane. Placing the slab module in a resonant cavity; The laser surface of the laser medium is cooled by a flowing coolant. The invention eliminates the drawback of adding too many mirrors to realize high gain using multi-loop device, and realizes degenerate four-wave mixing in one dimension or two dimensions at the same time in a linear cavity structure. The design device of the two-dimensional body holographic grating laser is simple and compact in structure, andhas the characteristics of linearly amplifying high power while maintaining the fundamental transverse mode unchanged.

The invention relates to the technical field of middle-infrared band laser, in particular to a dual-wavelength pumping middle-infrared four-wave mixing fiber laser of an all-fiber structure. The dual-wavelength pumping middle-infrared four-wave mixing fiber laser of the all-fiber structure comprises a pulse fiber laser, a continuous fiber laser, a wavelength division multiplexer and a non-linear soft glass fiber; pump light generated by the pulse fiber laser and anti-Stokes signal light generated by the continuous fiber laser are coupled through the wavelength division multiplexer for being transmitted in the non-linear soft glass fiber and generating a degeneration four-wave mixing effect, and finally middle-infrared band Stokes lasers are obtained. The dual-wavelength pumping middle-infrared four-wave mixing fiber laser is of the all-fiber structure, thereby simplifying the overall design and improving the coupling efficiency of pumping lasers; the pulse fiber laser is adopted for pumping, so that quite high peak power is provided, and the length of the middle-infrared soft glass fiber can be reduced; the anti-Stokes signal light is output continuously, and therefore the problem of time synchronization between the pumping light and the signal light does not need to be considered.

The invention discloses a single-beam near-degenerate four-wave mixing microscope device and method, and the method comprises the steps: carrying out the dispersion compensation of a laser pulse transmitted by a Ti sapphire laser through a pair of prisms, cutting off the laser pulse at 781nm through an ultra-steep long-pass filter, reflecting the laser pulse through a dichroscope, and focusing thelaser pulse on a to-be-measured sample through an objective lens; a reflection signal on a to-be-detected sample is collected by the objective lens, sequentially penetrates through the dichroscope and the band-pass filter and then is guided into the first photomultiplier; transmission signals on a sample to be detected are gathered through the condensing lens and then are divided into a transmission light beam and a reflection light beam through the beam splitter, incident laser of the transmission light beam is filtered out through the first ultra-steep short-pass filter, and then the transmission light beam is focused through the lens and guided into the high-resolution integrated spectrograph to record spectral data. And the reflected light beam is reflected by the reflector, then filtered by the second ultra-steep short-pass filter and finally guided into the second photomultiplier for four-wave mixing imaging. The method has the advantages of being simple, cheap and easy to operate.

The invention provides a nonlinear medium multi-polarization optical calibration device based on a degenerate four-wave mixing effect. The device comprises a laser (1), a first half-wave plate (2), a first polarization beam-splitting cube (3), a first reflector (4), a second half-wave plate (5), a second polarization beam-splitting cube (6), a third half-wave plate (7), a second reflector (8), a fourth half-wave plate (9), a third reflector (10), a fourth reflector (11), a vector light generation device (12), a third polarization beam-splitting cube (13), a focusing lens (14), a nonlinear optical action unit (15), a calibration recording device (16) and a polarization switcher (17). The multi-polarization optical path structure is innovatively designed, so that multiple pumping laser beams and polarization switching laser beams with multiple polarization states are simultaneously generated based on the same laser source, multi-polarization optical calibration of a nonlinear medium is realized, and the multi-polarization optical calibration device has a wide application prospect.

The invention discloses a configurable optical signal all-optical edge detection system. The system comprises a first erbium-doped fiber amplifier which is used for amplifying the power of a pump optical signal, a tunable optical attenuator which is used for adjusting the power of the pump optical signal after power amplifying, a first fiber delay line and a second fiber delay line. The first andsecond fiber delay lines are used for adjusting the relative delay amount of the pump optical signal and a first phase-reversed optical signal, and advancing or delaying the propagation time of the pump optical signal relative to the first phase-reversed optical signal by tau, wherein tau is the transit time of an NRZ optical signal. The system further comprises a wavelength division multiplexer which is used for coupling the pump optical signal and the first phase-reversed optical signal into an optical signal, a highly nonlinear optical fiber which is used for generating a degenerate four-wave mixing nonlinear effect under the action of the coupled optical signal to acquire a first idler light, and a first optical band-pass filter which is used for extracting the first idler light to acquire a first edge pulse. According to the invention, the principle of four-wave mixing is used; delay is introduced between two signals; and a rising edge, a falling edge or double edges can be flexibly acquired.

The invention discloses a method for determining the origin of cultural relics based on DFWM spectrum technology: dissolving the cultural relics to be tested with 1% nitric acid solution, and converting lead compounds in the lead-containing cultural relics to be tested into lead atoms. Divide a laser beam into three beams with equal optical paths, and adjust the spatial positions of the three beams. A sample of lead atoms to be measured is set at the intersection of the three beams of light, and the three beams of light interact with the lead atoms together to generate a DFWM signal. Obtain the DFWM signal spectrum of the lead atom. The types of lead isotopes were analyzed according to the DFWM signal spectrum, and the concentration ratio between lead isotopes was obtained. Comparing the lead isotope concentration ratio with the mineral material lead isotope standard ratio, analyze and deduce the origin of the cultural relics and the source of the mineral material. The method of the invention can improve the isotope detection sensitivity, reduce the detection limit, reduce the sampling amount, and realize near-nondestructive detection, and the technical equipment is simple, easy to operate, and has ultra-high sensitivity and detection accuracy.

The embodiment of the invention provides an orthogonal holographic grating solid laser. The laser comprises a laser resonant cavity, a liquid cooling cavity, an activating element and a pumping source, wherein the laser resonant cavity is a linear resonant cavity and comprises an output mirror and a high-reflection mirror; the liquid cooling cavity comprises an inclined glass sheet, a vertical glass sheet and a pumping window glass sheet; the pumping source is used for emitting pumping light to the side surface of a cuboid-shaped activating element through the coupling device; the coupling device is used for coupling the pumping light emitted by the pumping source into the activating element. The minimum distance between the inclined glass sheet and the oscillating laser light-passing surface of the activating element is 0. 5mm, and the inclination angles of the inclined glass sheet in the two orthogonal directions range from 0.5 milliradians to 0.1 milliradians. Degeneration four wavemixing conditions are simultaneously met in two orthogonal planes inside the active element. The average threshold pumping power density of the degeneration four wave mixing is larger than 300 wattsper square centimeter. Before a mold selection device is added, the laser outputs orthogonal fraunhofer diffraction patterns.

The invention discloses a DFWM (Degenerate Four-Wave Mixing) spectroscopic technology based method for determining the date of cultural relics, which comprises the following steps of: dividing a laser beam by a beam splitting device into three beams to be incident into a sample to be determined; receiving a generated DFWM signal by a photoelectric detector; measuring the intensity of the DFWM signal to judge the content information of 14C; and reckoning the date of the cultural relics based on the decay theory of the 14C according to the content information of the 14C. The invention has the advantages of simple device, easy and feasible operation, and capability of eliminating Doppler widening and can overcome the deficiencies of poor dating precision, high sampling amount, complicated device, high operation difficulty, high cost and the like in the traditional isotope-dating technology.