We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the pr...We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light （no extra noise） for the probe beam is used.展开更多
The time-dependent four-wave mixing（FWM） is analyzed in a four-level double semiconductor quantum well. The results show that both the amplitude and the conversion efficiency of the FWM field are enhanced with incre...The time-dependent four-wave mixing（FWM） is analyzed in a four-level double semiconductor quantum well. The results show that both the amplitude and the conversion efficiency of the FWM field are enhanced with increasing the strength of two-photon Rabi frequency. Interestingly, when the one-photon detuning becomes stronger the control field corresponding to the maximum efficiency increases. Such a controlled enhanced FWM may be used to generate coherent short-wave length radiation, and it can have potential applications in quantum control and communications.展开更多
Interferences in the quantum fluctuations of the output fields are demonstrated in four-wave mixing processes inside a cavity, which is driven by two quantized fields at the signal and the idler frequencies. These int...Interferences in the quantum fluctuations of the output fields are demonstrated in four-wave mixing processes inside a cavity, which is driven by two quantized fields at the signal and the idler frequencies. These interferences depend on the phase fluctuations of the input fields and induce mode splitting in the transmission spectra.展开更多
Frequency conversion is pivotal in nonlinear optics and quantum optics for manipulating and translating light signals across different wavelength regimes.Achieving frequency conversion between two light beams with a s...Frequency conversion is pivotal in nonlinear optics and quantum optics for manipulating and translating light signals across different wavelength regimes.Achieving frequency conversion between two light beams with a small frequency interval is a central challenge.In this work,we design a pair of coupled silicon microrings wherein coupled-induced modesplitting exists to achieve a small frequency shift by the process of four-wave mixing Bragg scattering.As an example,the signal can be up or down converted to the idler which is 15.5 GHz spaced when two pumps align with another pair of split resonances.The results unveil the potential of coupled microring resonators for small interval frequency conversion in a high-fidelity,all-optical,and signal processing quantum frequency interface.展开更多
We present a theoretical study of four-wave mixing(FWM)in a degenerate two-level atomic system subject to a magnetic field whose Zeeman sublevels constitute a tripod-type atomic system,which is driven by a linearly po...We present a theoretical study of four-wave mixing(FWM)in a degenerate two-level atomic system subject to a magnetic field whose Zeeman sublevels constitute a tripod-type atomic system,which is driven by a linearly polarized field,and coupled and probed by two sets of left and right circularly polarized fields.The optical effects of coherent hole burning(CHB)and electromagnetically induced transparency(EIT)are involved in the coherent system,among which the CHB has much larger response for the FWM than the EITs.Three situations of CHB are involved,and they are the solitary CHB,overlapped CHBs,and an overlap between CHB and EIT.The overlapped CHBs have the greatest magnitude of FWM signal among the three situations.Whereas,for the overlapped CHB and EIT,it has the smallest FWM magnitude,which is no more than one tenth of the former.While for the single CHB,the FWM magnitude is half of that of the overlapped CHBs.It is noted that,in the overlap between CHB and EIT,dual EIAs can be obtained,whose FWM signal also has an enhancement in comparison to no EIA.展开更多
Quantum squeezing is an important quantum resource for quantum metrology as it can improve the measurement precision.By enhancing the quantum squeezing level,the measurement precision can be further improved.Here,we e...Quantum squeezing is an important quantum resource for quantum metrology as it can improve the measurement precision.By enhancing the quantum squeezing level,the measurement precision can be further improved.Here,we experimentally implement quantum squeezing enhancement based on phase-sensitive cascaded four-wave mixing(CFWM)processes.The intensitydifference squeezing(IDS)between the two outputs of the phase-sensitive CFWM processes is enhanced to about 7.42 dB compared with IDS generated by the single four-wave mixing(FWM)process(about 3.31 or 4.01 dB).Such enhancement is enabled by both the intrinsic interference nature of phase-sensitive CFWM processes and the contribution of more gain from the two FWM processes.In addition,we measure IDS levels generated by phase-sensitive CFWM processes at different internalphase-locking points,which shows that the internal phase plays an important role in IDS enhancement.Our scheme provides a new method for improving the degree of IDS and may find potential applications in enhancing the measurement precision in quantum metrology.展开更多
We theoretically study the four-wave mixing(FWM)response in a quantum dot-cavity coupling system,where a two-level quantum dot(QD)is placed in an optical cavity while the cavity mode is coupled to the nanomechanical r...We theoretically study the four-wave mixing(FWM)response in a quantum dot-cavity coupling system,where a two-level quantum dot(QD)is placed in an optical cavity while the cavity mode is coupled to the nanomechanical resonator via radiation pressure.The influences of the QD-cavity coupling strength,the Rabi coupling strength of the QD,and the power of the pump light on the FWM intensity are mainly considered.The numerical results show that the FWM intensity in this hybrid system can be significantly enhanced by increasing the QD-cavity coupling strength.In addition,the FWM intensity can be effectively modulated by the Rabi coupling strength and the pump power.Furthermore,the effects of the cavity decay rate and the cavitypump detuning on the FWM signal are also explored.The obtained results may have potential applications in the fields of quantum optics and quantum information science.展开更多
We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system(NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a st...We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system(NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a strong driving field and a weak probe field. The bistable behavior of the steady-state photon number and the mechanical steady-state positions are discussed. Further, we tune bistability by tuning all the coupling frequencies involved in the system and amplitude of the driving field. The present study provides the possibility of realization of a controllable optical switch depending on atom-field coupling, optomechanical coupling, electrostatic Coulomb coupling, and threshold power. In addition, we discuss that the non-linear effect of the hybrid NEOMS generates the four-wave mixing(FWM) process. Moreover, we show that the FWM process can be suppressed by the atom-field detuning and cavity-field detuning, which exhibits low photon transmission.展开更多
This paper presents a theoretical study of wavelength dependence four-wave-mixing （FWM） spectroscopy in a micrometric thin atomic vapour. It compares three cases termed as mismatched case I, matched case and mismatc...This paper presents a theoretical study of wavelength dependence four-wave-mixing （FWM） spectroscopy in a micrometric thin atomic vapour. It compares three cases termed as mismatched case I, matched case and mismatched case II for the probe wavelength less, equal and greater than the pump wavelength respectively. It finds that Dicke- narrowing can overcome width broadening induced by Doppler effects and polarisation interference of thermal atoms, and high resolution FWM spectra can be achieved both in matched and mismatched wavelength for many cases. It also finds that the magnitude of the FWM signal can be dramatically modified to be suppressed or to be enhanced in comparison with that of matched wavelength in mismatched case I or II. The width narrowing and the magnitude suppression or enhancement can be demonstrated by considering enhanced contribution of slow atoms induced by atom-wall collision and transient effect of atom-light interaction in a micrometric thin vapour.展开更多
The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation res...The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.展开更多
Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induce...Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induced sidebands, which is based on the proper use of a continuous-wave and a pulse as light sources. We find that a mass of sidebands are generated in the modulation instability resonance region, and the power of the sideband increases with not only the peak power of the pump pulse but also the continuous-wave power which acts as a seed. The research will provide guidance for fiber communication and sensing systems using wavelength division multiplexing technology.展开更多
Two-photon resonant nondegenerate four-wave mixing （NFWM） with the addition of a coupling field in Ba atomic vapour has been studied. We find that coherence of the atomic level transitions leads to suppression of th...Two-photon resonant nondegenerate four-wave mixing （NFWM） with the addition of a coupling field in Ba atomic vapour has been studied. We find that coherence of the atomic level transitions leads to suppression of the NFWM signal, giving rise to a dip with a linewidth that is linearly proportional to the intensity of the coupling field.展开更多
By designing and fabricating a series of dual-interferometer coupled silicon microrings, the coupling condition of the pump, signal, and idler beams can be engineered independently and then we carried out both the con...By designing and fabricating a series of dual-interferometer coupled silicon microrings, the coupling condition of the pump, signal, and idler beams can be engineered independently and then we carried out both the continuous-wave and pulse pumped four-wave mixing experiments to verify the dependence of conversion efficiency on the coupling conditions of the four interacting beams, respectively. Under the continuous-wave pump, the four-wave mixing efficiency gets maximized when both the pump and signal/idler beams are closely operated at the critical coupling point, while for the pulse pump case, the efficiency can be enhanced greatly when the pump and converted idler beams are all overcoupled. These experiment results agree well with our theoretical calculations. Our design provides a platform for explicitly characterizing the four-wave mixing under different pumping conditions, and offers a method to optimize the four-wave mixing, which will facilitate the development of on-chip all-optical signal processing with a higher efficiency or reduced pump power.展开更多
The controllable optical mirror is experimentally accomplished in a A-type three-level atomic system coupled with standing wave. It is shown that the reflection of probe light results from electromagnetically-induced-...The controllable optical mirror is experimentally accomplished in a A-type three-level atomic system coupled with standing wave. It is shown that the reflection of probe light results from electromagnetically-induced-transparency-based four-wave mixing, therefore the reflection efficiency is highly dependent on the angle for phase matching condition between the probe and coupling fields. The measured reflection spectra show good agreement with dispersion compensation theory.展开更多
In this paper,an efficient 8-channel 32Gbps RoF(Radio over Fiber)system incorporating Bessel Filter(8/32 RoFBF)has been demonstrated to reduce the impact of non-linear transmission effects,specifically Four-Wave Mixin...In this paper,an efficient 8-channel 32Gbps RoF(Radio over Fiber)system incorporating Bessel Filter(8/32 RoFBF)has been demonstrated to reduce the impact of non-linear transmission effects,specifically Four-Wave Mixing(FWM).The simulation results indicate that the proposed 8/32 RoF-BF system provides an optimum result w.r.t.channel spacing(75 GHz),input source power(0 dBm)and number of input channels(8).In comparison with the existing RoF system,the proposed 8/32 RoF-BF system has been validated analytically and it is found that the performance of the proposed system is in close proximity particularly in FWM sideband power reduction of the order of 4 dBm for the 8-channel 32Gbps RoF system.展开更多
We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental re...We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal（idler） field g_（s（i））^（2） decreases with the intensity of signal injection. After applying narrow band filter in signal（idler） band, the value of g_（s（i））^（2） decreases from 1.9 ± 0.02（1.9 ± 0.02） to 1.03 ± 0.02（1.05 ± 0.02） when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results.Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network.展开更多
Cascaded fiber geometry with the dispersion of each fiber decreasing is proposed to enhance the multiple four-wave mixing（FWM） generation. The first fiber with relatively large dispersion initiates and accelerates t...Cascaded fiber geometry with the dispersion of each fiber decreasing is proposed to enhance the multiple four-wave mixing（FWM） generation. The first fiber with relatively large dispersion initiates and accelerates the expansion of multiple FWM, and the second fiber with small dispersion would allow the phase-matching process（thus the spectrum broadening）to keep going. Numerical and experimental results show that with this geometry not only multiple FWM expansion can be accelerated, but also the efficiency of multiple FWM products can be effectively improved with shorter fibers.展开更多
A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-5...A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-50 ps/km. Detection principle is deduced and relationship of the power of idler waves and DMGD is analyzed. With various chromatic dispersion(CD)values, different line widths and different optical signal noise ratio(OSNR) values, the simulations are carried out. The simulation results show that this new DMGD monitoring method is less affected by different line widths and has a high tolerance for OSNR.展开更多
We demonstrate the generation of the coherent 420 nm laser via parametric four-wave mixing process in Rb vapor.A single 778 nm laser with circular polarization is directly injected into a high-density atomic vapor,whi...We demonstrate the generation of the coherent 420 nm laser via parametric four-wave mixing process in Rb vapor.A single 778 nm laser with circular polarization is directly injected into a high-density atomic vapor,which drives the atoms from the 5S1/2 state to the 5D5/2 state with monochromatic two-photon transition.The frequency up-conversion laser is generated by the parametric four-wave mixing process under the phase matching condition.This coherent laser is firstly certified by the knife-edge method and a narrow range grating spectrometer.Then the generated laser power is investigated in terms of the power and frequency of the incoming beam as well as the density of the atoms.Finally,a 420 nm coherent laser with power of 19μW and beam quality of Mx^2=1.32,My^2=1.37 is obtained with optimal experimental parameters.This novel laser shows potential prospects in the measurement of material properties,information storage,and underwater optical communication.展开更多
Based on color-locking noisy field correlation in three Markovian stochastic models, phase dispersions of the Raman- and Rayleigh-enhanced four-wave mixing （FWM） have been investigated. The phase dispersions are mod...Based on color-locking noisy field correlation in three Markovian stochastic models, phase dispersions of the Raman- and Rayleigh-enhanced four-wave mixing （FWM） have been investigated. The phase dispersions are modified by both linewidth and time delay for negative time delay, but only by linewidth for positive time delay. Moreover, the results under narrowband condition are close to the nonmodified nonlinear dispersion and absorption of the material. Homodyne and heterodyne detections of the Raman, the Rayleigh and the mixing femtosecond difference-frequency polarization beats have also been investigated, separately.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2011CB921601)the National Natural Science Foundation of China (Grant No. 11234008)+1 种基金the National Natural Science Foundation of China for Excellent Research Team (Grant No. 61121064)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111401130001)
文摘We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light （no extra noise） for the probe beam is used.
基金Project supported by the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1080)the National Natural Science Foundation of China(Grant Nos.51272158,11374252,and 51372214)+4 种基金the Changjiang Scholar Incentive Program,China(Grant No.[2009]17)the Shanghai Nano Special Foundation,China(Grant No.11nm0502600)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.12A140)the Science and Technology Foundation of Guizhou Province,China(Grant No.J20122314)the Hunan Provincial Innovation Foundation for Postgraduate,China(Grant No.CX2012B248)
文摘The time-dependent four-wave mixing（FWM） is analyzed in a four-level double semiconductor quantum well. The results show that both the amplitude and the conversion efficiency of the FWM field are enhanced with increasing the strength of two-photon Rabi frequency. Interestingly, when the one-photon detuning becomes stronger the control field corresponding to the maximum efficiency increases. Such a controlled enhanced FWM may be used to generate coherent short-wave length radiation, and it can have potential applications in quantum control and communications.
基金Project supported by the New Staff Research Support Plan of Xi’an Jiaotong University,China (Grant No. 08141015)
文摘Interferences in the quantum fluctuations of the output fields are demonstrated in four-wave mixing processes inside a cavity, which is driven by two quantized fields at the signal and the idler frequencies. These interferences depend on the phase fluctuations of the input fields and induce mode splitting in the transmission spectra.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFF0712800)。
文摘Frequency conversion is pivotal in nonlinear optics and quantum optics for manipulating and translating light signals across different wavelength regimes.Achieving frequency conversion between two light beams with a small frequency interval is a central challenge.In this work,we design a pair of coupled silicon microrings wherein coupled-induced modesplitting exists to achieve a small frequency shift by the process of four-wave mixing Bragg scattering.As an example,the signal can be up or down converted to the idler which is 15.5 GHz spaced when two pumps align with another pair of split resonances.The results unveil the potential of coupled microring resonators for small interval frequency conversion in a high-fidelity,all-optical,and signal processing quantum frequency interface.
基金supported by the Open Subject of the State Key Laboratory of Quantum Optics and Quantum Optics Devices(Grant No.KF202209).
文摘We present a theoretical study of four-wave mixing(FWM)in a degenerate two-level atomic system subject to a magnetic field whose Zeeman sublevels constitute a tripod-type atomic system,which is driven by a linearly polarized field,and coupled and probed by two sets of left and right circularly polarized fields.The optical effects of coherent hole burning(CHB)and electromagnetically induced transparency(EIT)are involved in the coherent system,among which the CHB has much larger response for the FWM than the EITs.Three situations of CHB are involved,and they are the solitary CHB,overlapped CHBs,and an overlap between CHB and EIT.The overlapped CHBs have the greatest magnitude of FWM signal among the three situations.Whereas,for the overlapped CHB and EIT,it has the smallest FWM magnitude,which is no more than one tenth of the former.While for the single CHB,the FWM magnitude is half of that of the overlapped CHBs.It is noted that,in the overlap between CHB and EIT,dual EIAs can be obtained,whose FWM signal also has an enhancement in comparison to no EIA.
基金supported by the National Natural Science Foundation of China(Grant Nos.12225404,11874155,91436211,11374104,and 12174110)the Innovation Program of Shanghai Municipal Education Commission(Grant No.2021-01-07-00-08-E00100)+7 种基金the Program of Shanghai Academic Research Leader(Grant No.22XD1400700)the Basic Research Project of Shanghai Science and Technology Commission(Grant No.20JC1416100)the Natural Science Foundation of Shanghai(Grant No.17ZR1442900)the Minhang Leading Talents(Grant No.201971)the Shanghai Sailing Program(Grant No.21YF1410800)the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0893)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)the 111 Project(Grant No.B12024).
文摘Quantum squeezing is an important quantum resource for quantum metrology as it can improve the measurement precision.By enhancing the quantum squeezing level,the measurement precision can be further improved.Here,we experimentally implement quantum squeezing enhancement based on phase-sensitive cascaded four-wave mixing(CFWM)processes.The intensitydifference squeezing(IDS)between the two outputs of the phase-sensitive CFWM processes is enhanced to about 7.42 dB compared with IDS generated by the single four-wave mixing(FWM)process(about 3.31 or 4.01 dB).Such enhancement is enabled by both the intrinsic interference nature of phase-sensitive CFWM processes and the contribution of more gain from the two FWM processes.In addition,we measure IDS levels generated by phase-sensitive CFWM processes at different internalphase-locking points,which shows that the internal phase plays an important role in IDS enhancement.Our scheme provides a new method for improving the degree of IDS and may find potential applications in enhancing the measurement precision in quantum metrology.
基金supported by the National Natural Science Foundation of China(Grant Nos.11504258,61775043 and 11805140)the Natural Science Foundation of Shanxi Province(Grant Nos.201801D221021 and 201801D221031)。
文摘We theoretically study the four-wave mixing(FWM)response in a quantum dot-cavity coupling system,where a two-level quantum dot(QD)is placed in an optical cavity while the cavity mode is coupled to the nanomechanical resonator via radiation pressure.The influences of the QD-cavity coupling strength,the Rabi coupling strength of the QD,and the power of the pump light on the FWM intensity are mainly considered.The numerical results show that the FWM intensity in this hybrid system can be significantly enhanced by increasing the QD-cavity coupling strength.In addition,the FWM intensity can be effectively modulated by the Rabi coupling strength and the pump power.Furthermore,the effects of the cavity decay rate and the cavitypump detuning on the FWM signal are also explored.The obtained results may have potential applications in the fields of quantum optics and quantum information science.
文摘We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system(NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a strong driving field and a weak probe field. The bistable behavior of the steady-state photon number and the mechanical steady-state positions are discussed. Further, we tune bistability by tuning all the coupling frequencies involved in the system and amplitude of the driving field. The present study provides the possibility of realization of a controllable optical switch depending on atom-field coupling, optomechanical coupling, electrostatic Coulomb coupling, and threshold power. In addition, we discuss that the non-linear effect of the hybrid NEOMS generates the four-wave mixing(FWM) process. Moreover, we show that the FWM process can be suppressed by the atom-field detuning and cavity-field detuning, which exhibits low photon transmission.
基金supported from the Major Program of Science Foundation of Xi’an University of Arts and Science
文摘This paper presents a theoretical study of wavelength dependence four-wave-mixing （FWM） spectroscopy in a micrometric thin atomic vapour. It compares three cases termed as mismatched case I, matched case and mismatched case II for the probe wavelength less, equal and greater than the pump wavelength respectively. It finds that Dicke- narrowing can overcome width broadening induced by Doppler effects and polarisation interference of thermal atoms, and high resolution FWM spectra can be achieved both in matched and mismatched wavelength for many cases. It also finds that the magnitude of the FWM signal can be dramatically modified to be suppressed or to be enhanced in comparison with that of matched wavelength in mismatched case I or II. The width narrowing and the magnitude suppression or enhancement can be demonstrated by considering enhanced contribution of slow atoms induced by atom-wall collision and transient effect of atom-light interaction in a micrometric thin vapour.
基金Project supported by the National Natural Science Foundation of China （Grant No 60577033）, the Specialized Research Fund for the Doctoral Program of Higher Education （Grant No 20050003010） and the Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology.
文摘The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61177073)the Specialized Research Fundfor the Doctoral Program of Higher Education of China (Grant No.20104307110020)+1 种基金the Fund of Innovation of Graduate School of National University of Defense Technology, China (Grant No.B110703)the Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2011B033)
文摘Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induced sidebands, which is based on the proper use of a continuous-wave and a pulse as light sources. We find that a mass of sidebands are generated in the modulation instability resonance region, and the power of the sideband increases with not only the peak power of the pump pulse but also the continuous-wave power which acts as a seed. The research will provide guidance for fiber communication and sensing systems using wavelength division multiplexing technology.
基金Project supported by the National Natural Science foundation of China （Grant Nos 10174096 and 10374113） and the National Program for Basic Research in China （Grant No 001CB309301）.
文摘Two-photon resonant nondegenerate four-wave mixing （NFWM） with the addition of a coupling field in Ba atomic vapour has been studied. We find that coherence of the atomic level transitions leads to suppression of the NFWM signal, giving rise to a dip with a linewidth that is linearly proportional to the intensity of the coupling field.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0303700)the National Natural Science Foundation of China(Grant Nos.61632021,11627810,11690031,and 11621091)Open Funds from the State Key Laboratory of High Performance Computing of China(HPCL,National University of Defense Technology)
文摘By designing and fabricating a series of dual-interferometer coupled silicon microrings, the coupling condition of the pump, signal, and idler beams can be engineered independently and then we carried out both the continuous-wave and pulse pumped four-wave mixing experiments to verify the dependence of conversion efficiency on the coupling conditions of the four interacting beams, respectively. Under the continuous-wave pump, the four-wave mixing efficiency gets maximized when both the pump and signal/idler beams are closely operated at the critical coupling point, while for the pulse pump case, the efficiency can be enhanced greatly when the pump and converted idler beams are all overcoupled. These experiment results agree well with our theoretical calculations. Our design provides a platform for explicitly characterizing the four-wave mixing under different pumping conditions, and offers a method to optimize the four-wave mixing, which will facilitate the development of on-chip all-optical signal processing with a higher efficiency or reduced pump power.
基金supported by the National Natural Science Foundation of China(Grant Nos.61308121 and 11274210)the National Basic Research Program of China(Grant Nos.2010CB923102 and 2011CB922203)
文摘The controllable optical mirror is experimentally accomplished in a A-type three-level atomic system coupled with standing wave. It is shown that the reflection of probe light results from electromagnetically-induced-transparency-based four-wave mixing, therefore the reflection efficiency is highly dependent on the angle for phase matching condition between the probe and coupling fields. The measured reflection spectra show good agreement with dispersion compensation theory.
文摘In this paper,an efficient 8-channel 32Gbps RoF(Radio over Fiber)system incorporating Bessel Filter(8/32 RoFBF)has been demonstrated to reduce the impact of non-linear transmission effects,specifically Four-Wave Mixing(FWM).The simulation results indicate that the proposed 8/32 RoF-BF system provides an optimum result w.r.t.channel spacing(75 GHz),input source power(0 dBm)and number of input channels(8).In comparison with the existing RoF system,the proposed 8/32 RoF-BF system has been validated analytically and it is found that the performance of the proposed system is in close proximity particularly in FWM sideband power reduction of the order of 4 dBm for the 8-channel 32Gbps RoF system.
基金Project supported by the National Natural Science Foundation of China(Grant No.11527808)the State Key Development Program for Basic Research of China(Grant No.2014CB340103)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120032110055)the Natural Science Foundation of Tianjin,China(Grant No.14JCQNJC02300)the Program for Changjiang Scholars and Innovative Research Team in University,Chinathe Program of Introducing Talents of Discipline to Universities,China(Grant No.B07014)
文摘We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal（idler） field g_（s（i））^（2） decreases with the intensity of signal injection. After applying narrow band filter in signal（idler） band, the value of g_（s（i））^（2） decreases from 1.9 ± 0.02（1.9 ± 0.02） to 1.03 ± 0.02（1.05 ± 0.02） when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results.Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network.
基金supported by the National Key Scientific Instrument and Equipment Development Project,China(Grant No.2014YQ510403)the National Natural Science Foundation of China(Grant Nos.61377039 and 51527901)
文摘Cascaded fiber geometry with the dispersion of each fiber decreasing is proposed to enhance the multiple four-wave mixing（FWM） generation. The first fiber with relatively large dispersion initiates and accelerates the expansion of multiple FWM, and the second fiber with small dispersion would allow the phase-matching process（thus the spectrum broadening）to keep going. Numerical and experimental results show that with this geometry not only multiple FWM expansion can be accelerated, but also the efficiency of multiple FWM products can be effectively improved with shorter fibers.
基金supported by the National Science Foundation of China (61574080)Research Center of Optical Communications Engineering & Technology,Jiangsu Province (ZXF201803)
文摘A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-50 ps/km. Detection principle is deduced and relationship of the power of idler waves and DMGD is analyzed. With various chromatic dispersion(CD)values, different line widths and different optical signal noise ratio(OSNR) values, the simulations are carried out. The simulation results show that this new DMGD monitoring method is less affected by different line widths and has a high tolerance for OSNR.
基金Project supported by the National R&D Program of China(Grant No.2017YFA0304203)the National Natural Science Foundation of China(Grant Nos.61875112,61705122,91736209,and 61728502)+2 种基金the Program for Sanjin Scholars of Shanxi Province,China,the Applied Basic Research Project of Shanxi Province,China(Grant No.201701D221004)the Key Research and Development Program of Shanxi Province for International Cooperation,China(Grant No.201803D421034)1331KSC。
文摘We demonstrate the generation of the coherent 420 nm laser via parametric four-wave mixing process in Rb vapor.A single 778 nm laser with circular polarization is directly injected into a high-density atomic vapor,which drives the atoms from the 5S1/2 state to the 5D5/2 state with monochromatic two-photon transition.The frequency up-conversion laser is generated by the parametric four-wave mixing process under the phase matching condition.This coherent laser is firstly certified by the knife-edge method and a narrow range grating spectrometer.Then the generated laser power is investigated in terms of the power and frequency of the incoming beam as well as the density of the atoms.Finally,a 420 nm coherent laser with power of 19μW and beam quality of Mx^2=1.32,My^2=1.37 is obtained with optimal experimental parameters.This novel laser shows potential prospects in the measurement of material properties,information storage,and underwater optical communication.
基金Project supported by the National Natural Science Foundation of China (Grant No 60678005)the Foundation for the Authorof National Excellent Doctoral Dissertation of China (Grant No 200339)+1 种基金the For Ying-Tong Education Foundation for Young Teachers in the Institutions of Higher Education of China (Grant No 101061)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No 20050398017)
文摘Based on color-locking noisy field correlation in three Markovian stochastic models, phase dispersions of the Raman- and Rayleigh-enhanced four-wave mixing （FWM） have been investigated. The phase dispersions are modified by both linewidth and time delay for negative time delay, but only by linewidth for positive time delay. Moreover, the results under narrowband condition are close to the nonmodified nonlinear dispersion and absorption of the material. Homodyne and heterodyne detections of the Raman, the Rayleigh and the mixing femtosecond difference-frequency polarization beats have also been investigated, separately.
