Transmission of 10 GHz,3.5 ps Optical Pulses Over 100-km Standard Fiber Using Mid-span Spectral Inversion

Transmission of 3.5ps optical pulses over 100-km standard fiber was demonstrated by employing phase conjugation in a semiconductor optical amplifier to compensate the chromatic dispersion.The pulses were broadened to 5 ps after transmission,which confirms the applicability of this technique to ultra high-bit-rate system beyond 40 Gb/s.     

光纤-光栅对激光脉冲压缩

本文报道用2m单模保偏光纤实现脉冲光谱加宽,经光栅对补偿后,将40ps脉冲压缩到小于10ps的实验结果,分析了影响光脉冲压缩质量的原因。实验结果与理论较好地吻合。     

Picosecond optical switching of a 1.5 μm active birefringent optical fiber loop filter using 1.3 μm control optical pulses and a 1.3 μm semiconductor optical amplifier

Less than 100ps, polarization-independent switching operation of an active birefringent optical fiber loop filter using 1.3 μm control optical pulses as well as a 1.3 μm semiconductor optical amplifier (SOA) has been demonstrated. In the proposed SOA-based active birefringent filter operating at 1.55 μm wavelength, 1.3 μm SOA is employed to control the polarization-mode dispersion in the loop part. By injecting 1.3 μm ps gain-switched optical control pulses into the SOA, 1.5 μm input signals can be switched from the transmission port to the reflection port with less than 100 ps rise time.     

超短光脉冲发生器的研制

本文叙述了用半导体激光器产生光脉冲的基本原理,介绍了用电脉冲驱动AlGaAs/GaAs双异质结激光器产生ps光脉冲的线路原理及实验结果。     

用ICCD作光开关测量储存环中光学速调管谐波超辐射

用高通断比ICCD作为快速光开关,在中国科学技术大学的800MeV电子储存环上建造了一套光学速调管谐波超辐射测量系统,从每隔106个自发辐射脉冲1个谐波超辐射脉冲所形成的脉冲链里选出超辐射脉冲,测量谐波辐射的相干增强因子和谱宽。     

用ICCD作光开关测量储存环中光学速调管谐波超辐射

 用高通断比ICCD作为快速光开关,在中国科学技术大学的800MeV电子储存环上建造了一套光学速调管谐波超辐射测量系统,从每隔106个自发辐射脉冲1个谐波超辐射脉冲所形成的脉冲链里选出超辐射脉冲,测量谐波辐射的相干增强因子和谱宽。     

长波长1.3μm直接调制InGaAsP/InP半导体激光器产生超短光脉冲

利用长波长1.3μm InGaAsP/InP半导体激光器,在直接调制下获得了重复频率为1GHz,脉宽为19.3ps的超短脉冲。     

40 Gb/s信号的全光3R再生

研制出以注入锁模光纤激光器进行时钟恢复、电吸收调制器（EAM）作光判决门进行信号再整形的新型全光3R再生器,成功地运行于40Gb／s。理论和实验证明锁模环形激光器腔内放置的可调谐光滤波器的透射谱形状对时钟的脉宽有显著影响,超高斯透射谱的光滤波器利于获得窄时钟光脉冲,腔内放置这样的滤波器使恢复的时钟光脉冲谱宽达0．44nm、脉宽6ps、时间抖动小于1ps。最佳选择用作光判决的开关门的参量,改善了开关门的传输函数,使其接近阶跃函数,并使得开关窗宽度达到最佳。对于被剩余色散恶化的40Gb／s归零码信号进行了3R再牛,再生后达到了无误码。     

Experimental study of actively mode-locked semiconductor laser with grating external cavity

In this paper,complete mode-locking optical pulses have been obtained froman actively mode-locked GaAs/GaAlAs semiconductor laser with grating external cavity.Theshortest optical pulse is 7.3 ps measured by second harmonic generation(SHG)autocorrelator.The repetition rate is 995.12 MHz and the central wavelength is 798.4 nm.The effect ofmodulation frequency,modulation current,and bias current on the optical pulses width areinvestigated.     

新型金属团簇(Et_4N)_3WOS_3Cu_3I_4的皮秒光限幅特性研究

应用波长为532nm,脉冲宽度为40ps的激光脉冲研究了新型金属团簇(Et4N)3WOS3Cu3I4的光限幅性能。实验结果表明,该金属团簇在皮秒激光脉冲的作用下,具有很强的光限幅特性。利用非线性吸收的唯象理论对实验结果进行了分析。     

微微秒超短脉冲的光学压缩

在研究了短光纤(L～L_w)中受激喇曼散射的斯托克斯脉冲对基波脉冲能量箝位效应的基础上进行了脉冲压缩实验。以高泵浦功率(P=1600W)注入长度为8.95m绿光单模光纤中,采用双光程的光栅对压缩结构,并引入空间频率窗口滤除自相位调制光谱的非线性啁啾部分,将40ps的锁模Nd:YAG倍频光脉压缩至<5ps。     

利用超连续谱光源产生超短光脉冲

利用光纤中的各种非线性效应,获得了重复频率为２．５ＧＨｚ、光谱宽度达６０ｎｍ的超连结续谱超短光脉冲源。利用两个带宽分别为０．４ｎｍ及１．２ｎｍ的可调谐滤波器,从超连续光谱的不同波长处获得了脉宽为５．７ｐｓ及３．６ｐｓ的超短光脉中。由实验规律发现,在多种非线性效应中,四波混步效应对超连续光谱的形成有重要作用。     

Ultrafast interband pumping of quantum‐cascade structures: A feasibility study of a THz pulse amplifier

Gain spectra of a three‐well GaAs/AlGaAs quantum‐cascade structure under interband pumping by ultrashort optical pulses are studied within the framework of the density matrix theory. A mathematical model for intersubband kinetics is derived taking into account many‐body interactions and ultrafast interband optical pumping. It is found that pulsed interband pumping leads to an increase in intersubband gain by an order of magnitude, which is characterised by 1 ps rise time and 8 ps recovery time under pumping by 100 fs pulses with a peak intensity of 100 MW/cm². Possible implementations of the concept are highlighted. The results uncover a new possibility for ultrafast switching of the material gain in quantum‐cascade structures.     

光纤中稳态受激喇曼散射弧波研究

本文结出了描述光纤中受激喇曼散射过程的方程,通过对这些方程的讨论,得到了在稳态受激喇曼散射过程中可以存在弧波解的结论.这一理论可用于超短脉冲的产生.     

脉宽对超快激光平衡光学互相关测距影响的研究

采用基于平衡光学互相关的超快激光绝对距离测量方法对大气中一段15m的空间距离进行了测量。仿真了不同脉冲宽度、不同光强损耗对平衡互相关信号的影响,理论分析表明脉宽展宽对平衡互相关信号影响较大。采用中心波长为1037nm、重复频率为260MHz的超快激光器光源,搭建了测距系统。实验验证了在脉宽分别为1.44ps、132fs时,对平衡互相关信号的影响,实验结果符合理论分析。研究了不同脉冲宽度对测量分辨力的影响,结果显示,采样时间为5ms,脉宽为1.44ps,测量分辨力不低于50μm;而当脉宽为132fs时,测量分辨力优于5μm。     

亚皮秒级时间分辨率的光取样示波器实验样机

利用自行开发的高稳定、低抖动和重复频率可调的“σ”型被动锁模光纤激光器作为高性能光学取样源,与待测的80 Gb/s光脉冲信号同时输入到100 m高非线性光纤中,通过四波混频效应实现了对被测光信号的全光采样。然后利用自行开发的数字信号处理与计算机图形显示软件,精确地重现了被测试的基于RZ码型的80 Gb/s光脉冲信号波形图。同时,还利用该光学取样示波器实验样机系统对重复频率为10 GHz、脉宽为1.8 ps的商用半导体主动锁模激光器的输出波形进行测量,所显示的脉冲宽度值为2.0 ps。这表明开发出的实验样机系统的时间分辨率优于900 fs。     

基于绝热孤子压缩效应的小基座孤子脉冲研究

高重复频率超短光脉冲产生技术是高速光时分复用(OTDM)系统的关键技术之一,而一般的超短脉冲源直接产生的脉冲往往不够窄,因此必须对光脉冲进行压缩后才能满足高速光通信系统的要求。采用360 m长的色散渐减光纤(DDF),成功将从再生锁模光纤激光器(RMLFL)输出的中心波长1546 nm、重复频率10 GHz、脉宽分别为5.40 ps和4.60 ps的光脉冲,绝热压缩为脉宽为1.93 ps和1.71 ps的小基座孤子脉冲,压缩因子分别为2.80和2.69。利用这种绝热孤子压缩方法得到的光脉冲质量较好,可以用于160 Gb/s的光时分复用系统。     

基于亚毫米尺度金属包覆波导的脉冲展宽

利用自由空间耦合技术,用超短脉冲激发亚毫米尺度对称金属包覆波导中的超高阶导模,提出一种脉冲展宽的新方法。由于超高阶导模的强色散性质,经过短距离的传输,即可使脉冲宽度迅速展宽。理论分析表明,1 ps的光脉冲在光波导中传输毫米量级距离后,脉冲展宽因子可达到1000倍。     

Experimental and theoretical studies of a high repetition rate fiber laser, mode-locked by external optical modulation

An experimental and theoretical study of a high repetition rate laser source operating on a novel mode-locking technique is presented. This technique relies on the fast saturation and recovery of a semiconductor optical amplifier induced by an external optical pulse and has been used to obtain 4.3 ps pulses at 20 GHz. A complete mathematical model of the fiber ring laser is presented describing the mode-locking process in the laser oscillator and providing solutions for the steady-state mode-locked pulse profile. The critical parameters of the system are defined and analyzed and their impact on the formation of the mode-locked pulses is examined. The comparison between the theoretical results and the experimental data reveals very good agreement and has allowed the optimization of the performance of the system in terms of its critical parameters.     

Optical Limiting and ExcitedState Nonlinear Optical Properties in Lead Phthalocyanine

1.IntroductionLeadphthalocyaninehasreceivedconsiderableattentionasitexhibitsstrongreversesaturableabsorption(RSA)behaviorLI].Thiskindoforganometalliccompoundcanbeusedasopticallimitingdevicetoprotecteyesandsensorsfromlaserhazard.Thenanosecondopticallimitingpropertyofleadphthalocyaninehasbeeninvestigatedyet[2].Inthispaper,thepicosecondopticallimitingbehaviorofleadphthalocyanine(Pbpc(CP)4)ispresentedandtheresultiscomparedwithC6o,areversesaturableabsorptionmaterialwhichhasbeenwidelystudied.The…