Influences of GVD on the characteristics of soliton in a passively mode-locked Er-doped fiber laser

In this paper, the characteristics of soliton in a passively mode-locked Er-doped fiber laser modeled by a non-distributed model are numerically investigated with the split-step Fourier method. Based on the analysis and model, sech2-shaped soliton is obtained by controlling the group velocity dispersion （GVD） and small-signal gain of the gain fiber. The law that the dispersion influences the characteristics of soliton in the mode-locked fiber laser is researched in net-cavity averaged anomalous dispersion regime.     

Dissipative Solitons characteristics in passively mode-locked Yb-doped fiber laser under limitation of gain saturation energy

This paper is devoted to research the characteristics of the dissipative solitons formed in a passively mode-locked Yb-doped fiber (YDF) laser under limitation of the gain saturation energy. The parabolic shape dissipative solitons with linear chirps are observed in the fiber laser. The influences of the gain saturation energy on pulse duration, peak power and single pulse energy of the dissipative solitons are investigated in-depth.     

Study on parameter optimization in a passively mode-locked Erbium-doped fiber laser

Optical soliton communication is the frontier research topic of optical fiber communication. In this paper, we study optical solitons generated by passively mode-locked Erbium-doped (Er-doped) fiber (EDF) laser. We analyze the variation of nonlinear equilibrium point parameter N of the passively mode-locked EDF laser in the role of group-velocity dispersion (GVD) and small-signal gain, and adjusting system parameter N is as close as to possible to 1. The ground state first-order optical soliton which generated through system parameter optimization of the passively mode-locked EDF laser will improve the efficiency and stability of optical soliton communication system. The research of this paper will have provided the theoretical foundation of parameter optimization in a passively mode-locked EDF laser. And it will be possible for the passively mode-locked fiber laser in optical fiber communication system to be applied from the laboratory stage to the practical application.     

掺Er石英光纤的1560nm光纤激光和超荧光

用Ar离子514.5nm激光泵浦掺Er石英光纤产生了1560nm的激光和超荧光输出。激光最大输出功率5.4mW,斜率效率9.5％;超荧光最大输出功率1.6mW,并观察到光纤超荧光的谱窄化现象。     

Study on the chaotic dynamics of the mode-locked fiber ring laser

In this paper, we study the chaotic dynamics of the mode-locked fiber laser by numerical simulation. The structures of the passively mode-locked fiber laser and the actively mode-locked fiber laser are studied by modeling and analysis. By appropriately adjusting the small signal gain of the optical fiber amplifier, we observe the period-doubling bifurcations and route to chaos in the passively mode-locked fiber laser based on nonlinear polarization rotation effect. Chaos in the actively mode-locked erbium-doped fiber laser is obtained by adjusting the elliptic modulus parameter of the active modulator and the intra-cavity length. Simulation results have theoretical significance for the practical application of chaotic soliton communication.     

一种主动锁模光纤激光器稳定性的新方法

介绍了光码分复用通信系统中超短脉冲光源的重要性,并对主动锁模光纤环型激光器的稳定性问题进行了分析,然后介绍了解决长期稳定性的两种常用方法,最后提出了一种利用温控来解决长期不稳定性的新方法.     

Manipulating dissipative soliton ensembles in passively mode-locked fiber lasers

We review our recent experimental and theoretical results addressing the dynamics of large numbers of solitons interacting in presence of a background in passively mode-locked erbium-doped fiber lasers. We first characterize experimentally the soliton rain complex dynamics, and then we focus on ordered soliton patterns. We report that, for suitable experimental parameters, a continuous wave can impose harmonic mode locking. Two levels of modeling for a mode-locked laser subjected to the external injection of a continuous wave are developed to support the latter observation. The first one is based on a scalar master equation, while the second one takes into account the mode-locking mechanism more accurately through a vectorial approach.     

非线性偏振旋转光纤激光器的原理与关键技术

非线性偏振旋转(NPR)锁模光纤激光器以其结构简单紧凑而备受关注,是光通信系统、光传感和光探测等的理想光源。介绍了非线性偏振旋转锁模激光器的研究进展,分析了其工作原理、锁模方法及关键技术,并按其腔内净色散的不同进行分类,分析其各自特点以及通过色散管理获得高能量超短脉冲的方法。     

Output characteristics of optical solitons in a passively mode-locked Yb-doped fiber laser

In this paper, we studied the output characteristics of optical soliton in a passively mode-locked ytterbium (Yb)-doped fiber laser by numerical simulation. The structure of the passively mode-locked Yb-doped fiber laser was studied by modeling and analysis. The influence of the inter-cavity average group velocity dispersion on pulse width, pulse peak power and single pulse energy of optical soliton and self-similar pulse was investigated. Simulation results were very instructive for the practical application of the passiavely mode-locked Yb-doped fiber lasers.     

Coherence analysis of noise-like pulses generated by an erbium-doped fiber mode-locked laser

The noise-like pulses(NLPs)with tunable fraction of the pedestal height in the whole intensity autocorrelation(AC)trace are numerically demonstrated in the designed erbium-doped fiber(EDF)mode-locked laser,which contains the saturable absorber(SA)with nonlinear polarization rotation(NPR),sinusoidal-shaped or Gaussian-shaped filter,two segments of EDFs,and two pieces of single-mode fibers(SMFs)with normal dispersion and anomalous dispersion,re-spectively.The pedestal ratio of the intensity AC trace can be tuned by changing the gain saturation energies of EDFs.The results show that when the net cavity dispersion is 1.06 ps2,the tuning range of the pedestal ratio for the NLPs can reach its maximum values,which are 0.51-0.89 and 0.58-0.88 for the sinusoidal-shaped and Gaussian-shaped fil-ters,respectively.In addition,an appropriate choice of filter bandwidth is also conducive to obtain a wide range of the tuning pedestal ratio for the intensity AC trace.     

光纤放大器中有限增益带宽对自相似脉冲放大演化的数值研究

通过求解包含超高斯增益系数滤波项的分布增益非线性薛定谔方程,模拟研究了短脉冲在有限增益带宽指数增益光纤放大器中的自相似演化行为及其差异。结果表明脉冲在不同指数增益分布放大器中传输时都会受到增益带宽的限制。相同输入脉冲在相同长度、相同总增益的指数上升、下降和双向分布放大器中放大时,在双向分布放大器中输出能量最高,输出脉冲线性啁啾特性最好,指数下降放大器输出能量最低,输出脉冲线性啁啾特性最差,指数上升放大器居两者之间。另外,总增益相同时,无论是指数上升、下降和双向分布放大器,初始增益系数较小,输出脉冲能量较高,脉冲线性啁啾特性较好。     

被动锁模光纤环形孤子激光器的自起动分析

本文从激光器工作的两种平衡态出发 ,具体分析了被动锁模光纤环形孤子激光器的自起动特性与其结构参数的关系 ,并用分裂步长法对激光器的自起动特性做了数值模拟 ,获得了稳定的孤子脉冲序列。     

耦合腔型光纤激光器的原理与进展

概述耦合腔型(俗称8字型)光纤激光器基本原理的基础上,分析了非线性光纤环形镜(NOLM)、非线性放大环形镜(NALM)和色散非均衡光纤环形镜(DI-NOLM)这3种主要的8字型光纤激光器的技术原理和相关研究进展。讨论了8字型光纤激光器在光子晶体光纤介质、多波长和有理数谐波锁模方向的最新研究进展,并总结了8字型光纤激光器当前的研究重点和技术发展前景。     

光纤环形激光器中锁模脉冲均匀性的理论分析和实验研究

从描述双折射光纤环形激光器动力学模型出发,模拟并分析了脉冲序列在非线性偏振旋转锁模光纤激光器环形腔内的演化过程,得出光纤快慢轴与起偏器之间的角度、以及双折射强度是影响锁模脉冲序列均匀性的重要因素,通过将普通单模光纤绕制成环产生应力双折射的方法进行了验证,并获得了中心波长1566．8nm、脉宽为1．5ps的稳定短脉冲序列。     

不同光纤组合中产生的超连续谱研究(本期优秀论文)

采用自制σ形腔自起振被动锁模掺铒光纤激光器泵浦不同的光纤组合产生超连续谱,对不同长度的色散位移光纤(DSF)、高非线性光纤(HNLF)和120m HNLF+102m DSF中产生的超连续谱进行比较和分析.结果表明DSF与HNLF的组合使用要比单独使用DSF获得的SC谱谱宽更宽,平坦性更好;DSF与HNLF的连接顺序不同,所产生的SC谱也不同;先接入HNLF后接入DSF更容易获得平坦的超连续谱,短波长一例的功率显著增高.     

高频CO2激光脉冲写入的新型长周期光纤光栅及其在光通信中的应用

报道了一种利用频率为几千赫兹的高频CO2激光脉冲的热冲击效应制作长周期光纤光栅的新技术。实验中，作者首次发现这种新型的长周期光纤光栅具有一些独特的光学特性，比如弯曲特性和横向负载特性等，这主要是因为用高频CO2激光脉冲写成的长周期光纤光栅的横截面折射率分布不对称所致。基于这种新型长周期光纤光栅，设计了一种用于减小掺铒光纤放大器噪声系数的ASE噪声滤波器和平坦掺铒光纤放大器增益谱的增益均衡器，此外，还利用这种新型长周期光纤光栅独特的弯曲和压力特性，研究设计了两种用于动态平坦掺铒光纤放大器增益谱的动态增益均衡器。     

四能级系统光纤激光放大器的理论分析

本文从理论上分析了属于四能级系统的光纤激光放大器的增益特性,得到了信号增益与光纤长度、掺杂离子浓度、泵浦光和信号光功率等参数之间的关系式,并进行了数值计算。对四能级系统的激光放大器的设计有一定的指导作用。     

谐波锁模SOA光纤环形激光器的改进方案及其数值研究

对谐波锁模半导体光放大器(SOA)光纤环形激光器的工作条件提出改进,并采用自再现理论对其进行了数值研究.数值结果表明:激光器在新的工作条件下,即调制SOA被高直流偏置,对自发辐射信号进行调制并提供锁模脉冲克服腔损耗所需的增益,而此时的增益SOA被低直流偏置充当增益补偿器,输出的锁模脉冲质量显著提高.     

熔锥光纤倏逝场作用石墨烯双波长锁模掺镱光纤激光器

报道了利用熔锥光纤石墨烯饱和吸收体实现1μm波段的双波长锁模掺镱光纤激光器(YDFL)。利用光学诱导沉积法,将水溶液中的石墨烯纳米复合物在光倏逝场的作用下沉积至熔锥光纤的锥腰部位。该石墨烯熔锥光纤器件作为可饱和吸收锁模部件具有制作灵活、全光纤结构以及高损伤阈值等优点。基于该器件的可饱和吸收及腔内双折射滤波特性,通过调节偏振控制器优化激光腔内偏振特性,实现了稳定的YDFL双波长锁模。该激光器的两个锁模波长分别为1034.77nm和1038.85nm,二次谐波锁模重复频率为1.09MHz,腔内单脉冲能量最大可达35nJ。     

利用多重尺度理论对暗孤子在变迹光栅中演化特性的研究

从光纤光栅中的耦合波理论出发,利用多重尺度理论推导出光栅中的有效薛定谔方程。并在正常色散区运用快速傅立叶方法数值模拟了暗孤子在升余弦变迹光纤光栅中的演化以及暗孤子之间的相互作用。结果表明,在一定条件下光纤光栅的正常色散区可以维持暗孤子的稳定传输,并且孤子的稳定性与f的取值（孤子离光子带隙的位置）和非线性系数有关。随着f的增大单孤子背景处出现震荡现象;而随着f的增大两个暗孤子中心和背景处都将出现震荡、演化产生灰孤子等现象,但暗孤子之间的相互作用始终很弱;而且f越大,两个孤子的稳定性对非线性效应越敏感。