• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    M id-infrared supercontinuum generation and itsapp lication on all-opticalquantization with different inputpulses*

    2019-05-11 07:36:14YanLi李妍andXinzhuSang桑新柱
    Chinese Physics B 2019年5期
    關(guān)鍵詞:李妍

    Yan Li(李妍)and Xinzhu Sang(桑新柱)

    State Key Laboratory of Information Photonicsand OpticalCommunications,Beijing University ofPostsand Telecommunications,Beijing 100876,China

    (Received 5December2018;revisedmanuscript received 17 February 2019;published online22 April2019)

    Keywords:m id-infrared,supercontinuum generation,all-opticalquantization

    1.Introduction

    Themid-infrared region is a very importantelectromagnetic radiation band containing two relatively transparentw indows in the atmosphere.It covers the characteristic spectral linesofmany importantmolecules.Therefore,a lightsource operating in this band is very suitable for long-distance transm ission in the atmosphere,as well as for gas sensing,free space communication,and high-precision medical and military applications.[1,2]Therefore,this region has attracted considerable interest from researchers.

    Supercontinuum generation refers to the fact thatmany new frequenciesaregenerated in thespectrum of the transmitted pulse when a high-power ultrashort optical pulse passes through a nonlinear optical medium,such as a solid,liquid,gas,or sem iconductor,ow ing to various nonlinear effects in themedium.Consequently,the output pulse spectral w idth is considerably broader than the incident pulse w idth.SCG relies on the interplay of nonlinear effects,such as selfphasemodulation(SPM)and four-wavemixing(FWM),and most SCG studies realized with optical f ibers are diff icult to integrate.[3–7]Many smartSCG schemesbased on variousopticalwaveguides covering the visible and near-infrared wavelength regions were reported by many research groups over theyears.[8,9]In themid-infraredwavelength region,SCG has attracted increasing research interest.[5,10,11]

    Comparedwith silicon-basedmaterialsand chalcogenide materials,in them id-infrared region,GaAswith a large nonlinear refractive index and aw ide transparency spectral range of 20μm has been w idely used as a substratematerial.[12,13]Therefore,it is very suitable for the generating the nonlinear effect in all-optical signal processing devices.AlGaAs is an alloy of GaAs and AlAs.When the A l content in A lGaAs changes,the refractive index of A lGaAs changes.[14–16]A fter yearsof development,the preparation technology of AlGaAs hasmatured,which results in easymass production and cost reduction.Thus far,theapplication of AlGaAswaveguides in nonlinearopticshasbeen extensively investigated.[14–16]

    Many practical applications related to all-optical signal processing,ultra-high-speed optical systems,and nonlinear optics require a large variety of pulse waveforms other than Gaussian or secant pulse waveforms.The characteristics of input pulses,such as the pulse w idth,pulse energy,initial chirping,and initial pulse shape are very critical from the viewpoint of pulse evolution.In recent years,rectangular and parabolic pulseshaveattracted considerableattention owing to their favorable properties and features,such as resistance to opticalwave breaking,self-similarity in shape,and enhanced linearity in chirp.[17–19]Parabolic pulses propagate self-sim ilarly in a dispersive medium with normal dispersion and nonlinearity.Therefore,the amplitude and w idth scaling depends only on amplif ier parameters and the input pulse energy.[20]Ow ing to such features,parabolic pulses f ind a w ide range of applications,such as pulse compression and f lat spectral broadening.[21–23]Recently,many simple approaches to the generation of parabolic pulses have been demonstrated using super-structured f iber Bragg grating technology,[22,24]dispersion-decreasing f iberswithnormal group-velocity dispersion,[17,21,23,25]or AWG.[26]

    The AOADC,which aims to overcome the drawbacks of electrical ADC,has attracted considerable attention.[27–31]As the key process of AOADC,many smart schemes of allopticalquantization techniquesdetermining thespeed and resolutionof conversionwereproposedwith nonlinearopticaleffects in optical f ibers,[28–36]while the vastmajority ofmature schemespertaining toopticalquantizationemploy solitonselffrequency shift(SSFS).[32–36]SCG in nonlinearmedia is an intensity-to-wavelength conversion of the input pulse,[37–40]and it is feasible for application in all-optical quantization.Several SCG-based quantization schemeswere demonstrated bymany research groups.[38–40]

    Here,simulationsof SCG in them id-infrared region and its application on all-optical quantization are studied for the f irst time based on an AlGaAs horizontal strip waveguide with different types of input pulses,such as parabolic pulse,hyperbolic-secantpulse and theGaussian pulse.Ow ing to the largenonlinear refractive index of A lGaAs,a strong nonlinear interaction is realized,and the required power consumption of the quantization scheme is reduced eff iciently.Compared with the hyperbolic-secant pulse and the Gaussian pulse,the parabolic pulseoffersadvantagesin termsofbroadening,SCG coherence,and ADC performance.Asa result,four-bitquantization resolution alongwith ENOB of3.99 bitand a signal-tonoise ratio(SNR)of24.02 dB areachieved with the parabolic pulse,3.97 bitand 23.45 dB with the hyperbolic-secantpulse,3.973 bitand 23.92 dBwith theGaussian pulse.

    2.Theoreticalmodeland waveguide design

    2.1.Theoreticalmodel

    At room temperature,the Sellmeier equations of A lxGa1-xAs can be approximated as follows:[3,15]

    whereλis thewavelength inmicrometers,and thecoeff icients A,B,C,D are def ined as follows:

    where,x represents themolarcontentofalum inum in A lGaAs.

    The dynam ic processof pulsepropagation in the AlGaAs waveguide can be modeled with the generalized nonlinear Schr¨odinger equation(GNLSE)[41](Eq.(3))and solved with the fourth-orderRunge–Kutta formula where A(z,t)is the slow ly varying envelope of the electric f ield,αis linear lossof thewaveguide,andβn(ω)is the n-th order dispersion parameter coeff icientat the center frequency ω0.The last item on the right side of equation(3)represents third-ordernonlineareffects,including self-phasemodulation(SPM)and delayed Raman response.[42]

    hR(t)as theRaman response function of thewaveguide isgiven as follows:[42]Here,τ1andτ2are two adjustable parameters.In the normal dispersion regime,R(t)is negligible ow ing to the small contribution of the Raman effect to SC generation.In the normal dispersion region,themain causeof SCG is SPM.

    The hyperbolic-secant pulse occurs naturally in the contextof optical solitons and pulses em itted from a few modelocked lasers.[43]The temporalenvelopeexpressionassociated with such pulse isoften described with the follow ing form:and the temporal envelope of the Gaussian pulse can be described as

    Compared to the other pulse shapes,the parabolic pulse is maintained as the pulse undergoes exponential temporal and spectralbroadening aswellas an increase in amplitude.Furthermore,the parabolic pulse can resist the deleteriouseffects of wave breaking,which severely degrades the evolution of pulsesevolving in anonlinear dispersivemedium.Theanalyticalexpression foraparabolic pulseofenergy isas follows:

    In the above formulas,PPis the peak power of the pulse,TPis the temporal full-w idth athalf-maximum,and CPis the linear chirp coeff icient.Atmid-infrared,the parabolic pulse can begenerated in a tapered chalcogenidem icrostructured optical f iber,[44]or tapered silicon photonicw ires.[45]

    2.2.Waveguide design

    Asshown in Fig.1(a),thewaveguide isusedwith a strip structure.The core domain consists of Al0.18Ga0.82As,substratedomain ismadeof Al0.8Ga0.2As,and theupper cladding region isair.Specif ically,the dispersive value of the TEmode is smaller than that of the TM mode.Hence,the quasi-TE mode is selected as the propagation mode for this waveguide.The full-vector f inite elementmethod was used to analyze themode f ield distribution.The w idth w=6μm and height h=2.5μm of thewaveguideareoptim ized by analyzing the effectof thewaveguide geometricalparameterson the dispersion and effectivemode area formaximalnonlinear interaction.Mostof theguided-modeenergy is conf ined tightly within the core.

    Fig.1.(a)Designed waveguide and(b)transverse prof ile of electric f ield forquasi-TE polarization.

    The nonlinear coeff icient,γ0=2πn2/λ0Aeff,is determined by two factors,namely,nonlinear refractive index n2and effectivemode area Aeff(Eq.(9)).

    where F(x,y)is the modal distribution of the fundamental waveguidemode.

    TheGVD iscalculated as D=-(λ/c)d2neff/dλ2,where neffis the effective refractive index of the waveguide.Figure 2 shows the GVD parameter andβ2as a function of the wavelength.Bothβ2and D vanish at the zero-dispersion wavelength near 3.6μm.Aeffof the designed waveguide at 3μm is 0.058μm2,and the nonlinear coeff icient isγ=180.55W-1/m.The software COMSOL is used to calculate the effective index that yields the propagation constantβ.If thenumberofdispersion termsisinsuff icientduring SCG simulations,it is possible to result in inaccurate or deceptive results.Equation(3)issolved up to the11th orderof dispersion and the dispersion data are f itted with Taylor seriesexpansion up to the 11th order of dispersion.The high-order dispersion coeff icients at3μm are calculated,and they are listed in Table 1.

    Table1.The dispersion coeff icients.

    AlGaAs isaw idely used semiconductormaterial,and its production process is rathermature.AlGaAs grow th can be achieved by using molecular beam epitaxy ormetal organic chem icalvapor depositionwith GaAs crystalas the substrate.By using dry etching or wet etching,the desired waveguide shape can be obtained and subsequently packaged.

    3.Simulation and discussion

    The designed III–V waveguide described above is used to generate supercontinuum in them id-infrared region.The GNLSE given by Eq.(3)is numerically solved for SCG.The length of the waveguide L=1 cm.Figure 3 shows SCG with different input powers(P0)for the input pulse w idth T0=100 fs at-20 dB level and peak power of the input pulses set to 100mW,1W,10W,and 100W.SCG with different input pulse w idths(T0)is shown for the input power P0=10W at-20 dB and pulsew idth set to 100 fs,300 fs,500 fs,and 1 ps,respectively.When the initialw idth of the incidentpulseand the peak powerarenot the same,theeffect of dispersion and nonlineareffectson pulseevolution arealso different.The narrower the initial pulsew idth is,the stronger the dispersion effect is.The higher the peak powerof the initial pulse,the stronger the nonlinear effect is.Whether the input pulse is hyperbolic-secant(Figs.3(b),3(e),3(h),3(k);Figs.4(b),4(e),4(h),4(k)),Gaussian(Figs.3(c),3(f),3(i),3(l);Figs.4(c),4(f),4(i),4(l)),or parabolic(Figs.3(a),3(d),3(g),3(j);Figs.4(a),4(d),4(g),4(j)),the spectralw idth of SCG increasesas the inputpower increaseswith the same input pulse w idth.The input pulse w idth is narrower,and the spectrum of the supercontinuum is broader for the same input power.Compared with the hyperbolic-secant pulse and the Gaussian pulse,the parabolic pulse can generate a w ider spectrum for the same inputpulse power or pulsew idth.The inf luence of input power on the parabolic pulse ismore obvious than thaton the hyperbolic-secantpulse and the Gaussian pulse.

    Fig.2.Variation ofβ2 and D withwavelength.Bothβ2 and D vanish at the zero-dispersionwavelength near 3.6μm.

    Coherence describes the spectral randomness of SC under the inf luence of random amplitude and phase noise.If coherence is poor,the spectrum generated with different inputpulsesinto thewaveguideshows large random f luctuations ow ing to random power noise and phase noise,whichmeans the system is sensitive to the random noise in the incom ing signalwhen the coherence of SCG is low,and excessive randomnessof the spectrum leads to inconsistency in theamount of spectral spread determined at the same power,resulting in erroneous coding.A suitablemeasure of coherence for SCG is the degree of coherence associated with each spectral component.First-order coherence is def ined as follows:[42,43]where?A(λ)is the amplitude of the SC generated in the frequency domain.To obtain more accurate results,100 pairs with independent random power noise and phase noise are used in the simulation.

    Fig.3.Spectra obtained with different pumping powers(T0=100 fs).The input pulses of panels(a),(d),(g),and(j)are parabolic pulses.The inputpulsesofpanels(b),(e),(h),and(k)arehyperbolic-secantpulses.The inputpulsesof panels(c),(f),(i),and(l)areGaussian pulses.L=1.5 cm.

    Fig.4.Spectraobtainedwith differentpumpingw idths(P0=10W).The inputpulsesofpanels(a),(d),(g),and(h)are parabolic pulses.The inputpulses of panels(b),(e),(h),and(k)are hyperbolic-secant pulses.The input pulses of panels(c),(f),(i),and(l)are Gaussian pulses.L=1.5 cm.

    Fig.5.Degreesof coherence.The inputpulsesof panels(a),(d),(g),and(j)are parabolic pulses.The inputpulsesof panels(b),(e),(h),and(k)arehyperbolic-secantpulses.The inputpulsesof panels(c),(f),(i),and(l)areGaussian pulses,when T0=100 fs.

    Fig.6.Degreesof coherence.The inputpulsesof panels(a),(d),(g),and(j)are parabolic pulses.The inputpulsesof panels(b),(e),(h),and(k)arehyperbolic-secantpulses.The inputpulsesof panels(c),(f),(i),and(l)areGaussian pulses,when P0=10W.

    The degrees of coherence corresponding to Figs.3 and 4 are shown in Figs.5 and 6,respectively.Both degrees of coherence around 3μm are almost 1. The coherence of the parabolic pulse is better than that of the hyperbolicsecant pulse and the Gaussian pulse under the same conditions.Excellent coherence can ensure stability of the quantization scheme.On the contrary,a coding error can occurwhen the degree of coherence is not1.Thus,it is essential that the degreeof coherencebe close to 1 in quantization schemes that employ slicing SC.

    The schematic diagram of the proposed quantization scheme by slicing SC isshown in Fig.7.The sampled pulses with different peak powers are incident on the designed III–V waveguide.To indicate variations of the different pulses,two pulseswith different peak powers and the same central wavelengthλ0are plotted.Spectrum broadening of theoptical pulses occurs due to the interaction between waveguide dispersion and nonlinearity.Therefore,the intensity of the sampled pulse can be converted into the SC w idth of the optical parameters.Bymeasuring thew idth of the SC,the inputsampled pulse can be quantized.To determine the w idth of the generated SC,a set of f ilters can be placed in the long-wave direction at the inputpulse centerwavelength.At the output end ofeach f ilter,theopticalsignalsare converted into electrical signals by photodetectors,and these electrical signals are judged using comparators.[46,47]A decision threshold isset.If the detectoroutputexceeds the f ixed threshold,the stateof the port is“ON”,and themarked code is“1”.Otherw ise,the state of port is“OFF”,and the code is“0”.

    Fig.7.Schematic diagram of proposed spectralquantization(PD:photoelectric detector).

    For thisscheme,thew idth of the inputpulsewith a center wavelength of 3μm is set to 100 fs.The inputpulse power is increased from 200mW to 760mW.The-15 dB band-w idth of SCG ismeasured,as shown in Fig.8.Fifteen f ilters are used to slice thegenerated SC to achieve four-bitquantization resolution.A nonlinear relationship exists between the peak power of the inputpulse and thew idth of the SC,and special design of the non-uniform f ilters can improve the system resolution.Tables 1,2,and 3 list the centerwavelengths of the f ilters.The research onmid-infrared tunable f ilters isbecoming increasinglymature,[48–51]and tunable f ilterswith AlGaAs waveguideswasstudied,which can beused for integration.[49]

    Fig.8.Spectrum w idth for different inputpeak powers:(a)parabolic pulse,(b)hyperbolic-secantpulse,and(c)Gaussian pulse.

    Tab le2.The centerwavelength of the15 f ilters for the hyperbolic-secantpulse.

    Table3.The centerwavelength of the15 f ilters for the parabolic pulse.

    Tab le4.The centerwavelength of the15 f ilters for theGaussian pulse.

    Fig.9.Outputpeak powersof 15 f iltering portsspaced evenly asa function of inputpeak powers((a),(b),(c)).The corresponding quantization transfer functionof the four-bitquantization scheme((d),(e),(f)).Differentialnonlinearerrorand integralnonlinearerrorwith the f iltering ports((g),(h),(i)).The inputpulsesof panels(a),(d),and(h)are parabolic pulses.The inputpulsesof panels(b),(e),and(h)arehyperbolic-secant pulses.The inputpulsesof panels(c),(f),and(i)are Gaussian pulses.

    On the Stokes side of the pump wavelength,the change in f ilter power from mark“0”to“1”to the next f ilter from“0”to“1”corresponds to the leastsignif icantbit(LSB)of the designed f ilter.Nos.1 to 15 in Fig.9(a),9(b),and 9(c)represent the f irst to the f ifteenth f ilters.When the inputpulse is hyperbolic-secant,3151 nm–3203 nm range is selected as the f iltering area,and 5.9μW isused as thepower threshold.From Fig.9(b),it can be seen that the powerused forquantif ication is460mW–760mW,and the LSB is20mW.The corresponding transfer function isshown in Fig.9(e),where the solid line(blue)represents the ideal transfer function,and the dashed line(red)represents thesimulated transfer function.When the input pulse is Gaussian,we set 3151 nm–3203 nm as the f iltering rangeand 3μW as thepower threshold.From Fig.9(b),the power used for quantif ication is 410 mW–760 mW,and the LSB is 23.3mW.The corresponding transfer function is shown in Fig.9(e).When the input pulse is parabolic,we set3314 nm–3374 nm as the f iltering area and 1.9μW as the power threshold.From Fig.9(a),the power used for quantif ication is 360 mW–760 mW,and the LSB is 26.7 mW.The larger LSB is benef icial for improving ENOB.The corresponding transfer function is shown in Fig.9(d).It can be seen from Figs.9(d)),9(e),and 9(f)thatdifference exists between the simulated and the ideal values.The calculated differential nonlinear error(DNL)and the integral nonlinear error(INL)errors[50]are shown in Figs.9(g),9(h),and 9(i).Themaximum value of DNL is 0.18 LSB and that of INL is 0.17 LSB when the input pulse is hyperbolic-secant.The maximum value of DNL is0.17 LSB and thatof INL is0.15 LSB when the input pulse is Gaussian.Themaximum value of DNL is 0.09 LSB and that of INL is 0.11 LSB when the inputpulse isparabolic.The effectivenumberof bits(ENOB)and the signal-to-noise ratio(SNR)were found to be 3.97 bit and 23.54 dB for the hyperbolic-secant pulse,3.973 bit and 23.92 dB for theGaussian pulse,and 3.99 bitand 24.02 dB for the parabolic pulse.

    With increased spectral bandw idth,this scheme can be used to achievehigh speed andmulti-bitquantization.Asseen from Fig.10,when NOB=2,3,4,the corresponding ENOB of parabolic pulse ishigher than thatof gaussian pulseand hyperbolic secant pulse,but the difference is not large.When NOB=5,6,the difference between the ENOB corresponding to theparabolic pulseand theENOB of theGaussian pulseand the hyperbolic secantpulse is high up to 0.5 bit.Therefore,it can be seen from the Fig.10,compared with gaussian pulse and hyperbolic secantpulse,theparabolic pulse showsnoticeable improvementof ENOB.The advantagesof the parabolic pulsearemoreobviousathigher resolutions.

    Fig.10.Relationship between NOB and ENOB for differentpulses.

    4.Conclusion

    In summary,the inf luences of pulse w idth,peak power,and pulse type on SCG with an AlGaAs horizontal strip waveguide is investigated in themid-infrared region,theireffects on all-optical quantization of AOADC are also dicussed with differentinputpulses.Resultsshow thatwhen the typeof inputpulse isparabolic,the SCG isbroaderand hashigher coherence.Ow ing to the high nonlinear coeff icientof the III–V waveguide in them id-infrared region in thisscheme,the input pulse peak power required to reach theappropriate SCG is reduced,resulting in low power consumption and an integrated quantization scheme.The generated high-coherence SC can be used for AOADC applications to reduce coding error and enhance ENOB.The SNR and ENOB are 23.54 dB and 3.97-bit for thehyperbolic-secantpulse,23.92 dB and 3.973-bit for theGaussian pulse,and 24.02 dB and 3.99-bit for theparabolic pulse.In an M-bit(M>4)quantization scheme,the advantagesof theparabolic pulsew illbemoreobvious.

    猜你喜歡
    李妍
    秋葉翻了個身
    詩潮(2023年8期)2023-08-23 03:44:05
    Multi-band asymmetric transmissions based on bi-layer windmill-shaped metamaterial*
    論一顆蛀牙的長成
    大眾健康(2019年9期)2019-10-11 04:06:12
    Analysis on the innovation principle of operating system development history
    Sine-Gordon Solitons and Breathers in Rod-like Magnetic Liquid Crystals under External Magnetic Field?
    抬頭看看天
    小說月刊(2017年7期)2017-07-10 07:47:58
    美味的壽司
    Study of the natural vibration characteristics of water motion in the moon pool by the semi-analytical method*
    What’s the Future of Paper Books(節(jié)選)
    The Broken of the American Dream
    黄色a级毛片大全视频| 老司机午夜十八禁免费视频| 午夜精品久久久久久毛片777| 日本撒尿小便嘘嘘汇集6| 亚洲精品国产一区二区精华液| 搡老熟女国产l中国老女人| 夜夜骑夜夜射夜夜干| 夜夜骑夜夜射夜夜干| 亚洲精品在线观看二区| 国产精品一区二区在线观看99| 制服诱惑二区| 国产精品一区二区免费欧美| 老汉色∧v一级毛片| 午夜福利视频在线观看免费| 亚洲,欧美精品.| 在线天堂中文资源库| 成人手机av| 日本撒尿小便嘘嘘汇集6| 精品高清国产在线一区| 午夜免费成人在线视频| 狠狠婷婷综合久久久久久88av| 一区二区av电影网| 亚洲成人手机| 在线观看人妻少妇| 日本a在线网址| 亚洲免费av在线视频| 99国产精品99久久久久| 嫩草影视91久久| 国产在线免费精品| 国产极品粉嫩免费观看在线| 精品卡一卡二卡四卡免费| 日韩免费av在线播放| 99在线人妻在线中文字幕 | 国产色视频综合| 国产高清国产精品国产三级| 色综合婷婷激情| 男人舔女人的私密视频| 大陆偷拍与自拍| 精品一区二区三区四区五区乱码| 亚洲国产欧美网| 自线自在国产av| 国产亚洲欧美在线一区二区| 色婷婷av一区二区三区视频| 搡老熟女国产l中国老女人| 亚洲少妇的诱惑av| 亚洲欧美一区二区三区黑人| 成人三级做爰电影| 亚洲欧美激情在线| 中文字幕人妻丝袜一区二区| 久久午夜亚洲精品久久| 美女福利国产在线| 97在线人人人人妻| cao死你这个sao货| 国产精品一区二区在线不卡| 每晚都被弄得嗷嗷叫到高潮| av有码第一页| 热99re8久久精品国产| 一级毛片精品| 精品人妻1区二区| 国产精品自产拍在线观看55亚洲 | 女同久久另类99精品国产91| 中文字幕最新亚洲高清| 一级毛片电影观看| 国产成人一区二区三区免费视频网站| 国产男女内射视频| 久久影院123| av国产精品久久久久影院| 国产老妇伦熟女老妇高清| 精品人妻1区二区| 狂野欧美激情性xxxx| 国产人伦9x9x在线观看| 王馨瑶露胸无遮挡在线观看| 国产精品1区2区在线观看. | 法律面前人人平等表现在哪些方面| 91九色精品人成在线观看| 十八禁高潮呻吟视频| 大陆偷拍与自拍| 在线av久久热| 国产成人精品久久二区二区免费| 国产精品麻豆人妻色哟哟久久| 黄频高清免费视频| 91麻豆av在线| 久久久精品区二区三区| 一进一出好大好爽视频| 中文字幕人妻丝袜制服| 侵犯人妻中文字幕一二三四区| 又紧又爽又黄一区二区| 午夜免费成人在线视频| 亚洲,欧美精品.| 纵有疾风起免费观看全集完整版| 一级,二级,三级黄色视频| 精品久久久久久电影网| 成人影院久久| 色婷婷久久久亚洲欧美| 国产一区二区三区视频了| 亚洲精品久久成人aⅴ小说| 亚洲九九香蕉| 亚洲国产精品一区二区三区在线| 青草久久国产| 777米奇影视久久| 色播在线永久视频| 国产欧美日韩一区二区三区在线| 国产一卡二卡三卡精品| 狠狠狠狠99中文字幕| 一进一出抽搐动态| 国产在线精品亚洲第一网站| 高清欧美精品videossex| 欧美 日韩 精品 国产| 欧美激情 高清一区二区三区| 久久国产精品大桥未久av| 久久午夜亚洲精品久久| 法律面前人人平等表现在哪些方面| 日日摸夜夜添夜夜添小说| 欧美精品亚洲一区二区| 好男人电影高清在线观看| 99国产综合亚洲精品| 久久精品国产99精品国产亚洲性色 | 青青草视频在线视频观看| 欧美日韩亚洲高清精品| 日本a在线网址| 高清在线国产一区| 不卡一级毛片| 日韩欧美免费精品| 男女高潮啪啪啪动态图| 国产成人欧美| 男女之事视频高清在线观看| 制服人妻中文乱码| 新久久久久国产一级毛片| 男女下面插进去视频免费观看| 国产精品欧美亚洲77777| 在线观看66精品国产| 中文字幕人妻丝袜一区二区| 亚洲人成伊人成综合网2020| 国产精品国产高清国产av | 桃红色精品国产亚洲av| 啦啦啦在线免费观看视频4| 黑人巨大精品欧美一区二区蜜桃| 69av精品久久久久久 | 午夜福利免费观看在线| 欧美另类亚洲清纯唯美| 亚洲国产成人一精品久久久| 久久人妻福利社区极品人妻图片| 成人18禁高潮啪啪吃奶动态图| 欧美日韩亚洲高清精品| 欧美激情高清一区二区三区| 91老司机精品| 十八禁高潮呻吟视频| 纵有疾风起免费观看全集完整版| 亚洲精品av麻豆狂野| 极品少妇高潮喷水抽搐| 日韩大码丰满熟妇| 天天躁日日躁夜夜躁夜夜| 精品人妻在线不人妻| 男人操女人黄网站| 国产老妇伦熟女老妇高清| 欧美老熟妇乱子伦牲交| 99热网站在线观看| 妹子高潮喷水视频| 日本a在线网址| 丰满迷人的少妇在线观看| 三上悠亚av全集在线观看| 91av网站免费观看| 久久国产精品人妻蜜桃| 波多野结衣av一区二区av| 久久天躁狠狠躁夜夜2o2o| 一级毛片女人18水好多| 国产真人三级小视频在线观看| 中国美女看黄片| 精品国内亚洲2022精品成人 | 国产欧美日韩一区二区三| av福利片在线| 水蜜桃什么品种好| 国产精品.久久久| 久久久久视频综合| 成人av一区二区三区在线看| cao死你这个sao货| av国产精品久久久久影院| 欧美av亚洲av综合av国产av| 久久久国产成人免费| 国产精品久久久久成人av| 国产一卡二卡三卡精品| 亚洲成a人片在线一区二区| 国产精品一区二区精品视频观看| 国产一区二区三区在线臀色熟女 | 久久久久久亚洲精品国产蜜桃av| 精品国产超薄肉色丝袜足j| 国产免费现黄频在线看| 成人18禁在线播放| 99国产极品粉嫩在线观看| 中文字幕另类日韩欧美亚洲嫩草| 成人国产av品久久久| 亚洲精品粉嫩美女一区| 精品熟女少妇八av免费久了| 激情在线观看视频在线高清 | 国产成人av教育| 欧美国产精品va在线观看不卡| 欧美精品一区二区免费开放| 啦啦啦视频在线资源免费观看| 免费少妇av软件| 国产av又大| 亚洲自偷自拍图片 自拍| 亚洲视频免费观看视频| 自拍欧美九色日韩亚洲蝌蚪91| 国产无遮挡羞羞视频在线观看| 国产亚洲精品久久久久5区| 久久人妻av系列| 国产在线一区二区三区精| 啪啪无遮挡十八禁网站| 午夜福利影视在线免费观看| 啦啦啦 在线观看视频| 777米奇影视久久| 婷婷成人精品国产| 最近最新中文字幕大全免费视频| 亚洲中文日韩欧美视频| av视频免费观看在线观看| 久久久精品国产亚洲av高清涩受| 不卡一级毛片| 国产精品 国内视频| 色综合婷婷激情| 久久天堂一区二区三区四区| 日韩中文字幕视频在线看片| 亚洲专区中文字幕在线| 成人手机av| 在线十欧美十亚洲十日本专区| 国产一区二区三区综合在线观看| 夫妻午夜视频| 天天躁夜夜躁狠狠躁躁| 亚洲五月婷婷丁香| 高清欧美精品videossex| 十八禁网站免费在线| 成人三级做爰电影| 精品亚洲成a人片在线观看| 丝袜人妻中文字幕| 老熟妇乱子伦视频在线观看| 精品国产一区二区三区久久久樱花| 欧美久久黑人一区二区| 久久亚洲精品不卡| 国产精品秋霞免费鲁丝片| 精品少妇一区二区三区视频日本电影| 亚洲av日韩在线播放| 亚洲色图综合在线观看| 免费在线观看完整版高清| 少妇的丰满在线观看| 国产成人欧美| 国产精品 国内视频| 午夜91福利影院| 久久精品国产亚洲av香蕉五月 | 美国免费a级毛片| 日本精品一区二区三区蜜桃| 久久久国产一区二区| 日韩制服丝袜自拍偷拍| 后天国语完整版免费观看| 下体分泌物呈黄色| 狠狠狠狠99中文字幕| 久久国产亚洲av麻豆专区| 日韩欧美一区二区三区在线观看 | 色尼玛亚洲综合影院| 99国产极品粉嫩在线观看| 欧美精品一区二区免费开放| 麻豆乱淫一区二区| 大型av网站在线播放| 王馨瑶露胸无遮挡在线观看| 高清视频免费观看一区二区| www.精华液| 亚洲精品在线观看二区| 日本一区二区免费在线视频| 欧美亚洲日本最大视频资源| 69av精品久久久久久 | 亚洲精华国产精华精| 久久精品国产综合久久久| www.999成人在线观看| 午夜成年电影在线免费观看| 男女无遮挡免费网站观看| 性少妇av在线| 黑人巨大精品欧美一区二区蜜桃| 精品国产乱码久久久久久小说| 在线观看66精品国产| 久久人妻熟女aⅴ| 亚洲精品av麻豆狂野| 亚洲成人国产一区在线观看| 国产高清videossex| 欧美精品高潮呻吟av久久| 一进一出抽搐动态| 午夜精品国产一区二区电影| 久久久国产成人免费| 少妇 在线观看| 狠狠狠狠99中文字幕| 精品国产国语对白av| 91精品三级在线观看| 国产高清videossex| 日韩视频在线欧美| 欧美成人免费av一区二区三区 | 热99久久久久精品小说推荐| 欧美中文综合在线视频| 亚洲国产看品久久| 精品久久蜜臀av无| 乱人伦中国视频| 欧美人与性动交α欧美精品济南到| 在线观看66精品国产| 国产福利在线免费观看视频| 国产精品久久久久成人av| 人人妻人人澡人人爽人人夜夜| 国产成人av激情在线播放| 80岁老熟妇乱子伦牲交| 可以免费在线观看a视频的电影网站| 大型黄色视频在线免费观看| 国产国语露脸激情在线看| 精品国产亚洲在线| 桃红色精品国产亚洲av| 日本黄色视频三级网站网址 | 欧美国产精品一级二级三级| 精品视频人人做人人爽| 亚洲精品国产一区二区精华液| 少妇精品久久久久久久| 可以免费在线观看a视频的电影网站| 嫩草影视91久久| 久久香蕉激情| 亚洲国产欧美日韩在线播放| 亚洲一卡2卡3卡4卡5卡精品中文| 蜜桃国产av成人99| 久9热在线精品视频| 精品少妇一区二区三区视频日本电影| 亚洲黑人精品在线| 黄色视频在线播放观看不卡| 人成视频在线观看免费观看| 欧美日韩av久久| 欧美激情高清一区二区三区| 一本久久精品| 老司机影院毛片| 少妇猛男粗大的猛烈进出视频| 捣出白浆h1v1| 啦啦啦中文免费视频观看日本| 欧美黑人欧美精品刺激| 亚洲精品久久午夜乱码| 十八禁网站网址无遮挡| 国产99久久九九免费精品| 久久天堂一区二区三区四区| 精品第一国产精品| 精品乱码久久久久久99久播| 色视频在线一区二区三区| 欧美午夜高清在线| 久久人妻av系列| 午夜福利乱码中文字幕| 精品熟女少妇八av免费久了| 国产在线精品亚洲第一网站| 99久久精品国产亚洲精品| 久久久久网色| 欧美黑人欧美精品刺激| 视频区图区小说| 亚洲中文日韩欧美视频| 女人高潮潮喷娇喘18禁视频| 人成视频在线观看免费观看| 91老司机精品| 国产野战对白在线观看| 久久免费观看电影| 一级毛片精品| 一区二区日韩欧美中文字幕| 国产熟女午夜一区二区三区| 一本综合久久免费| 他把我摸到了高潮在线观看 | 亚洲欧美日韩另类电影网站| 捣出白浆h1v1| 亚洲国产欧美在线一区| 久久久国产欧美日韩av| 国产福利在线免费观看视频| 成人影院久久| 乱人伦中国视频| 中国美女看黄片| 九色亚洲精品在线播放| 亚洲人成电影观看| 国产成人欧美| 99久久国产精品久久久| 91成人精品电影| 一本色道久久久久久精品综合| 涩涩av久久男人的天堂| 狂野欧美激情性xxxx| 欧美av亚洲av综合av国产av| 国产激情久久老熟女| 99re在线观看精品视频| www.精华液| 乱人伦中国视频| 香蕉丝袜av| 国内毛片毛片毛片毛片毛片| 久久久久精品国产欧美久久久| 91字幕亚洲| 纵有疾风起免费观看全集完整版| 丁香六月欧美| 亚洲精品久久成人aⅴ小说| 黄色片一级片一级黄色片| 午夜激情av网站| 国产av精品麻豆| 99精品在免费线老司机午夜| 日韩欧美一区二区三区在线观看 | 天堂动漫精品| 丰满人妻熟妇乱又伦精品不卡| 色在线成人网| 一进一出抽搐动态| 丝袜在线中文字幕| 这个男人来自地球电影免费观看| 久久精品国产综合久久久| 亚洲男人天堂网一区| 69精品国产乱码久久久| 亚洲一区中文字幕在线| 国产免费现黄频在线看| 精品一区二区三区av网在线观看 | 欧美激情极品国产一区二区三区| 18禁裸乳无遮挡动漫免费视频| 丝袜在线中文字幕| 亚洲av第一区精品v没综合| xxxhd国产人妻xxx| 国产xxxxx性猛交| 久9热在线精品视频| 亚洲专区国产一区二区| 人成视频在线观看免费观看| 中文亚洲av片在线观看爽 | 国产日韩一区二区三区精品不卡| 亚洲熟妇熟女久久| 香蕉久久夜色| 欧美在线一区亚洲| 亚洲欧美激情在线| 免费在线观看黄色视频的| 自线自在国产av| 亚洲免费av在线视频| 国产真人三级小视频在线观看| 欧美国产精品一级二级三级| www.999成人在线观看| 国产1区2区3区精品| 俄罗斯特黄特色一大片| 成年人午夜在线观看视频| 日韩人妻精品一区2区三区| 麻豆乱淫一区二区| 国产极品粉嫩免费观看在线| tube8黄色片| 免费久久久久久久精品成人欧美视频| 精品乱码久久久久久99久播| 美女福利国产在线| 男女免费视频国产| 成人特级黄色片久久久久久久 | 亚洲成人免费电影在线观看| 一进一出抽搐动态| 日本欧美视频一区| √禁漫天堂资源中文www| 蜜桃在线观看..| 怎么达到女性高潮| 国内毛片毛片毛片毛片毛片| 国产精品1区2区在线观看. | 亚洲成国产人片在线观看| 一区福利在线观看| 怎么达到女性高潮| 日韩欧美免费精品| 色综合婷婷激情| 国产精品av久久久久免费| 757午夜福利合集在线观看| 久久天躁狠狠躁夜夜2o2o| 国产一区二区三区视频了| 国产麻豆69| 久久国产精品男人的天堂亚洲| 久久久精品94久久精品| 十八禁网站网址无遮挡| 一本久久精品| 久久精品成人免费网站| 欧美 日韩 精品 国产| 亚洲成a人片在线一区二区| av在线播放免费不卡| 精品第一国产精品| 国产精品自产拍在线观看55亚洲 | 精品人妻在线不人妻| 国产成人av激情在线播放| 亚洲人成77777在线视频| 岛国在线观看网站| 如日韩欧美国产精品一区二区三区| 欧美+亚洲+日韩+国产| 少妇的丰满在线观看| 久久毛片免费看一区二区三区| 免费在线观看日本一区| 丝袜美腿诱惑在线| 变态另类成人亚洲欧美熟女 | 欧美在线黄色| 久久人妻av系列| 成人亚洲精品一区在线观看| 曰老女人黄片| 99香蕉大伊视频| 天天躁狠狠躁夜夜躁狠狠躁| 最近最新中文字幕大全电影3 | 老鸭窝网址在线观看| 国产一区二区三区视频了| 两人在一起打扑克的视频| 久久亚洲精品不卡| 啦啦啦视频在线资源免费观看| 久久人妻熟女aⅴ| 日韩一区二区三区影片| 久久这里只有精品19| 国产不卡一卡二| 午夜免费鲁丝| 一夜夜www| 国产精品亚洲一级av第二区| 亚洲人成伊人成综合网2020| av视频免费观看在线观看| 中文字幕av电影在线播放| 日本a在线网址| 在线观看www视频免费| 99久久精品国产亚洲精品| 两个人免费观看高清视频| 亚洲色图综合在线观看| 亚洲一码二码三码区别大吗| 悠悠久久av| 国产精品亚洲av一区麻豆| 1024香蕉在线观看| 中文字幕av电影在线播放| 国产福利在线免费观看视频| 12—13女人毛片做爰片一| av又黄又爽大尺度在线免费看| 亚洲男人天堂网一区| 国产亚洲精品一区二区www | 人人妻人人添人人爽欧美一区卜| 久久中文字幕人妻熟女| 麻豆成人av在线观看| 精品一区二区三区四区五区乱码| 人妻 亚洲 视频| 真人做人爱边吃奶动态| a级毛片在线看网站| 91字幕亚洲| 午夜成年电影在线免费观看| 成人免费观看视频高清| 国产精品1区2区在线观看. | 精品免费久久久久久久清纯 | 国产精品免费视频内射| 夜夜爽天天搞| 老司机在亚洲福利影院| 久久精品成人免费网站| 9热在线视频观看99| 天天操日日干夜夜撸| 久久精品亚洲熟妇少妇任你| 51午夜福利影视在线观看| 我要看黄色一级片免费的| 天天添夜夜摸| 搡老熟女国产l中国老女人| 国产精品av久久久久免费| 精品国内亚洲2022精品成人 | 热re99久久精品国产66热6| 国产一区二区激情短视频| 亚洲欧美日韩高清在线视频 | 国产精品 欧美亚洲| 久久久精品免费免费高清| av天堂久久9| 俄罗斯特黄特色一大片| 激情视频va一区二区三区| 国产单亲对白刺激| 老汉色av国产亚洲站长工具| 欧美性长视频在线观看| 亚洲色图 男人天堂 中文字幕| 欧美av亚洲av综合av国产av| 精品少妇久久久久久888优播| 久久精品国产亚洲av高清一级| 12—13女人毛片做爰片一| 熟女少妇亚洲综合色aaa.| av有码第一页| 又紧又爽又黄一区二区| 最新在线观看一区二区三区| 99国产精品免费福利视频| 五月天丁香电影| 在线观看免费午夜福利视频| 在线观看免费视频网站a站| 成人精品一区二区免费| 久久久久国内视频| 涩涩av久久男人的天堂| 国产日韩一区二区三区精品不卡| 天堂中文最新版在线下载| 成人av一区二区三区在线看| 欧美另类亚洲清纯唯美| 91成年电影在线观看| 中文亚洲av片在线观看爽 | www日本在线高清视频| 精品国产乱码久久久久久小说| 两个人免费观看高清视频| 丰满少妇做爰视频| 91国产中文字幕| 精品一区二区三卡| 亚洲成人手机| 大香蕉久久成人网| 搡老岳熟女国产| 看免费av毛片| 久久精品91无色码中文字幕| 97在线人人人人妻| 日本av手机在线免费观看| 夜夜爽天天搞| videos熟女内射| 久久青草综合色| 夜夜爽天天搞| 91成人精品电影| av国产精品久久久久影院| 最近最新免费中文字幕在线| 精品亚洲成国产av| 国精品久久久久久国模美| 久久精品成人免费网站| 亚洲国产毛片av蜜桃av| 国产成人免费无遮挡视频| 国产成人影院久久av| 免费少妇av软件| 亚洲成人手机| 香蕉国产在线看| 日韩欧美一区视频在线观看| 午夜91福利影院| 麻豆国产av国片精品| 精品一区二区三卡| 青青草视频在线视频观看| 国产一区二区三区在线臀色熟女 | 麻豆乱淫一区二区| 一区二区三区精品91| 欧美日韩亚洲高清精品| 免费不卡黄色视频| 成年动漫av网址| 黄片播放在线免费| 免费高清在线观看日韩| 下体分泌物呈黄色|