Synchronization of Chaotic Intensities and Phases in an Array of N Lasers

A linear array of N mutually coupled single-mode lasers is investigated. It is shown that the intensities of N lasers are chaotically synchronized when the coupling between lasers is relatively strong. The chaotic synchronization of intensities depends on the location of the lasers in the array. The chaotic synchronization appears between two outmost lasers, the second two outmost lasers, etc. There is no synchronization between nearest neighbors of the lasers. If the number of N is odd, the middle laser is never synchronized between any lasers. The chaotic synchronization of phases between nearest lasers in the array is examined by using the analytic signal and the Gaussian filter methods based on the peak of the power spectrum of the intensity. It can be seen that the message of chaotic intensity synchronization is conveyed through the phase synchronization.     

二极管泵浦高能激光研究进展和展望

高能激光广泛应用于材料加工、科学研究、空间碎片清除、军事应用等领域。二极管泵浦高能激光具有结构紧凑,系统简单、全电驱无限弹仓的特点,近年来,各类二极管泵浦高能激光围绕着同时实现高功率、高效率、高光束质量这一总目标发展迅速。详细综述了国内外高平均功率块状固体激光、高功率可见光波段激光、高峰值功率激光、高功率光纤激光、碱金属蒸气激光等二极管泵浦高能激光的研究进展,并对其发展趋势进行了展望。     

Q‐switched and modelocked all‐fiber lasers based on advanced acousto‐optic devices

The interest in all‐fiber lasers is stimulated by the inherent advantages they have over bulk lasers in aspects such as heat dissipation and robustness. The performance of Q‐switched and modelocked fiber lasers can benefit enormously from the development of all‐fiber configurations. A fiber laser with strictly all‐fiber components can fulfil the requirements of mechanical stability, low maintenance, enhanced power efficiency, simplified assembly process, and low cost. In this framework, recent developments infiber acousto‐optic devices are reviewed that have demonstrated new possibilities for actively Q‐switched distributed feedback fiber lasers, modelocking lasers and doubly active Q‐switched modelocked lasers. The aim is to demonstrate the great potential of infiber devices for the active control of different types of fiber lasers.     

Bistable phase locking in rocked lasers

We investigate analytically and numerically the dynamics of single mode lasers with periodic ac injection (rocked lasers). Such lasers show phase bistability as the phase of the light emitted by such lasers can lock to either of two values shifted by π. Locking regimes for different lasers are studied showing that the system response is strongly modified in class B lasers due to the influence of relaxation oscillations.     

高能激光技术进展与面临的挑战

文章分析和比较了几种高能激光器技术发展现状和面临的挑战,以及各自可能适用的范围.特别对二极管抽运固体激光器和光纤激光器的几种束相干合成方法和光束质量评价方法进行了分析和讨论.二极管抽运固体激光器和光纤激光器近十年来异军突起,被人们看作是继化学激光器后的第二代高能激光器.光纤激光器进展要比二极管抽运固体激光器滞后5到10年.对几十万瓦以上的激光器来说,在相当长的时间内仍然要靠化学激光器.     

锁模光纤激光器时变动力学

锁模激光器除了可以产生稳定的超短脉冲以外,还可产生一系列重要的非平衡态动力学过程.这些快速变化的动力学过程有助于理解超快激光器和相关非线性系统的动力学,也对超快激光器的稳定性设计有重要指导意义.随着超快探测技术的发展,锁模激光器超快动力学的研究取得了一系列突破.介绍了锁模激光器几个典型的非平衡态动力学过程,包括锁模启动...     

正色散激光器中的增益导引孤子

采用非线性薛定谔方程模拟了全正色散介质激光器中实现脉冲锁模输出的动态过程,理论表明,不同于工作于净色散为负的孤子锁模激光器以及腔内具有色散延迟线净色散为正的色散管理孤子和自相似脉冲锁模激光器,在纯正色散介质构成的锁模激光器中,增益饱和和增益窄化对形成稳定的锁模脉冲起重要的作用,在两者的作用下脉冲形成增益导引孤子.采用不同的锁模方式在纯正色散光纤锁模激光器中得到了稳定的增益导引孤子锁模,实验结果与理论模拟一致. 关键词： 锁模 正色散 增益导引孤子     

固体激光器的灯泵浦和二极管泵浦方式比较

对固体激光器的灯泵浦和二极管泵浦方式进行了比较,详细分析了不同类型的固体激光器所适用的泵浦方式.指出二极管泵浦固体激光器是今后固体激光器的发展趋势.     

Silicon intersubband lasers

The critical design issues for unipolar silicon quantum-well intersubband lasers are investigated in this paper. Group IV lasing at near-infrared and middle-infrared wavelengths is analyzed for surface-emitting and edge-emitting geometries. Calculations show feasibility of SiGe/Si and SiGe/Si lasing. Silicon-on-insulator structures are proposed for index-guided lasers, vertical-cavity lasers and micro-cavity lasers     

水平腔面发射半导体激光器研究进展

近年来,水平腔面发射半导体激光器具有高功率、高光束质量及易封装集成等优良性能,已成为激光器领域的研究热点。本文详细阐述了几种水平腔面发射半导体激光器的结构设计、工作原理以及激光输出特性,并对该激光器国内外最新研究进展与发展现状进行了总结和论述。在此基础上,对该激光器的研究方向和发展趋势进行了分析与展望。目前,水平腔面发射半导体激光器的激光输出功率可达瓦级,美国Alfalight公司引入曲线形光栅的单一发射器输出功率可达73 W。随着应用领域的不断拓展,中远红外波段水平腔面发射激光器将成为未来的研究焦点。     

Passive Q-switching and mode-locking for the generation of nanosecond to femtosecond pulses

The passive and hybrid Q-switching and mode-locking of solid-state lasers, dye lasers, semiconductor lasers and gas lasers is reviewed. The dynamics of saturable absorbers and reverse saturable absorbers is illustrated. The nanosecond pulse generation by passive and hybrid Q-switching of low-gain active media is described. The picosecond and femtosecond pulse generation by passive and hybrid mode-locking in low-gain and high-gain active media is analysed. The performance data of passively and hybridly mode-locked cw femtosecond dye lasers are collected. The pulse shortening of ultra-fast pulses with saturable absorbers in intra-cavity and extra-cavity configurations is discussed.     

LD泵浦Nd:YAG微片激光器

ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器结构简单紧凑，与半导体激光器相比，前者具有激光线宽窄、光束质量好、相干长度长等优点，因此在一些测量领域有着较好的应用前景。目前对ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的实验工作主要是获得单频、单模连续输出和线性频率调制特性研究。本文综述了近几年来ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的研究方向、成果及应用，主要介绍了各国对ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的调频特性的研究状况     

High-power quantum well remote junction laser and its electrical noise characteristics

We designed and fabricated new structure lasers, the high-power AlGaAs/GaAs remote junction (RJ) single quantum well (SQW) semiconductor lasers whose p–n junction was separated from the active layer. The RJ lasers showed marked reduction of threshold current during early aging period. This reduction was accompanied by a decrease of non-radiative recombination centers in the active layer. For the RJ SQW lasers, the relation between the low-frequency electrical noise and the lifetime of devices is different from the conventional SQW lasers.     

分布反馈光纤激光器弯曲特性的实验研究

为了研究分布反馈光纤激光器的弯曲特性,对光纤激光器输出波长和弯曲半径的关系进行了理论分析和实验研究.理论分析表明,光纤激光器输出波长变化量与弯曲半径平方的倒数为线性相关,并且随着弯曲半径的增大布拉格波长向短波长方向移动|实验中通过对3支不同波长的光纤激光器在弯曲半径分别为10 mm、20 mm、90 mm时输出波长的测量,验证了理论分析的正确性.实验中采用参考光纤激光器法排除环境干扰,对光纤激光器的激射功率进行了耐弯曲测试,并验证了光纤激光器斜率效率优越的抗弯曲特性.结果表明,在测试的32天内,待测光纤激光器激射功率变化量均小于2 dB,为分布反馈光纤激光器做为弯曲类传感应用的研究提供了重要的参考依据.     

Review of Tm and Ho materials; spectroscopy and lasers

A review of Tm and Ho materials is presented, covering some fundamental aspects on the spectroscopy and laser dynamics in both single and co-doped systems. Following an introduction to 2-μm lasers, applications and historical development, the physics of quasi-four level lasers, energy transfer and modeling are discussed in some detail. Recent developments in using Tm lasers to pump Ho lasers are discussed, and seen to offer some advantages over conventional Tm:Ho lasers. This article is not intended as a complete review, but as a primer for introducing concepts and a resource for further study.     

Theory of Dynamics In-Phase Locking and Quasi-Period Synchronization in Two Mutually Coupled Multi-Quantum-Well Lasers

We study dynamics in two mutually coupling multi-quantum-well lasers. We carry out theoretical and numerical analysis of synchronization, anti-synchronization, in-phase locking in the two identical lasers but detuning, in detain. It is proved that the coupling level determines stability of the lasers by analyzing the eigenvalueequation. Critical case of locking is discussed via the phase difference equation. Quasi-period and stable states in the two lasers are investigated via varying the current, detuning and coupling level.     

Static and Dynamic Analysis of Lasing Action from Single and Coupled Photonic Crystal Nanocavity Lasers

The single and coupled photonic crystal nanocavity lasers are fabricated in the InGaAsP material system and their static and dynamic features are compared. The coupled-cavity lasers show a larger lasing efficiency and generate an output power higher than the single-cavity lasers, results that are consistent with the theoretical results obtained by rate equations. In dynamic regime, the single-cavity lasers produce pulses as short as 113 ps,while the coupled-cavity lasers show a significantly longer lasing duration. These results indicate that the photonic crystal laser is a promising candidate for the light source in high-speed photonic integrated circuit.     

Recent progress in semiconductor lasers — cw GaAs lasers are now ready for new applications

Semiconductor lasers, first demonstrated in 1962, have spent a long time in development without finding many applications. (GaAl)As double heterostructure diode lasers with stripe structure have distinctive characteristics for cw operation with a pure mode, in addition to their compactness and ease of operation. Quick degradation of these lasers has been investigated and it was found that the degradation was caused by local crystalline defects produced by internal stresses and local weakness. Improvements based on the study have provided reliable lasers with an operating life of over several thousand hours. These new generation lasers will be useful for optical communications and other optical systems.     

Mutual injection locking and coherent combining of three individual fiber lasers

Mutual injection locking and coherent combining of three individual erbium-doped fiber lasers are reported. Theoretical model of the three fiber lasers under mutual injection is also analyzed. Under free running state, the far field beam profile is a simple intensity superposition as three incoherent beams. Under mutual injection locking, interference lobes with high contrast ratio are obtained in the far field of three fiber lasers, which shows that the three fiber lasers have good interference characteristic under mutual injection. The experimental results are in good agreement with the theoretical results. According to this method, we can also realize coherent beam combining in more fiber lasers.