GaInAsP/InP double-heterostructure lasers for fiber odtic communications

This paper reviews the performance of GaInAsP/InP double-heterostructure diode lasers prepared by liquid-phase epitaxy. These lasers have the advantage that exact lattice-matching between the GaIn-ASP active region and the InP substrate is possible for quaternary alloy compositions giving emission wavelengths over a range that includes 1.1-1.3 μm, the optimum region for optical communication systems utilizing fused silica fibers. Continuous operation at room temperature has been achieved in this region for proton-defined stripe (PDS), oxide-defined stripe (ODs), and junction-defined, buried-stripe (JDBS) lasers. The first three PDS devices to be life-tested have already logged over 6,000, 5,700, and 4,000 h, respectively, of cw operation at room temperature without any degradation.     

Frequency offsets in frequency-locked semiconductor lasers

A commonly used technique for frequency locking a laser is dithering the laser frequency and monitoring the first derivative of the laser transmission through an absolute reference. In semiconductor lasers, this frequency dithering can be obtained easily by dithering the injection current. However, this dithering also modulates the laser output power. Here we show that this modulation of the laser output power results in an offset of the locked laser frequency from the reference frequency. We derive analytical expressions for these frequency offsets for semiconductor lasers frequency-locked to a Fabry-Perot transmission peak, a Gaussian absorption line, and a Lorentzian absorption line.     

Single longitudinal mode,symmetrical three-cavity GaInAsP/InP lasers

Two ways of improving the mode-selection characteristics of diode lasers are analysed. The mode-selection mechanism and technological processes are presented for symmetrical three-cavity lasers, and the experimental results are in good agreement with theoretical results.     

Modal properties of all-active InGaAsP/InP microring lasers

An experimental investigation of the multimode dynamics of 1.55 μm-InGaAsP/InP microring lasers is demonstrated. Different operation regimes are observed, bidirectional multimode, unidirectional single mode, bidirectional single mode and mode-hopping. The extent of each of the above operation regimes is examined with respect to the ring current level, bus waveguide reflectivity and ring radius. The back-reflections generated from the bus waveguide facets are indirectly controlled via the bus waveguide current. In order to clarify the physical mechanisms beyond experimental results, a multimode model based on the rate equation approximation is utilized. The experimental results are in good agreement to those predicted by the multimode model.     

Core temperature in super-Gaussian pumped air-clad photonic crystal fiber lasers compared with double-clad fiber lasers

In this paper we investigate the core temperature of air-clad photonic crystal fiber (PCF) lasers pumped by a super-Gaussian (SG) source of order four. The results are compared with conventional double-clad fiber (DCF) lasers pumped by the same super-Gaussian and by top-hat pump profiles.      

外部光注入空间耦合半导体激光器高维混沌系统的增频与控制研究

提出外部光注入空间耦合半导体激光器系统,研究 外部光注入两激光器混沌振荡频率增强以及混沌控制等特点, 给出稳定频率失谐公式.研究表明,当单激光器注入时,注入激光器 呈现出三个混沌扩频区域;发现在强激光注入条件下,随着注入程度的 增加,注入激光器混沌振荡频率增强非常有效且可达到 3.5倍以上(尽管另一个激光器频率会缓慢下降); 随着注入光正频率失谐的增加,两激光器混沌振荡都能进一步增 强;发现混沌控制窗口,即在弱注入条件下两激光器可以被控制到单周 期、双周期、四周期、六周期等.当双激光器注入时,随着注入程度 的增加,两激光器混沌振荡频率 进一步增加, 且可达到3.5倍和2.65倍以上; 随着注入光正频率失谐增加, 两激光器混沌振荡频率增加.双激光器注 入控制混沌的一个窗口也被发现:即在强注入条件下两激光器可以被 控制到单周期、三周期、六周期等.最后详细给出了单激光注入系 统从单周期模式锁定到类周期再进入混沌增频的发展路径以及双 激光注入系统从混沌到类周期再进入单周期模式锁定的演化控制路径等.     

Semiconductor disk lasers for the generation of visible and ultraviolet radiation

Recent developments in semiconductor disk lasers (SDLs) generating visible or ultraviolet light are reviewed. After an introduction on potential applications, we discuss how the combination of vertical‐emitting semiconductor GaAs‐based structures and intra‐cavity nonlinear conversion techniques can be successfully exploited to uniquely meet demands for continuous‐wave radiation in the visible and ultraviolet spectral range. To do so, an overview of the device operating principles and performance is presented highlighting the underlying material considerations, semiconductor structural designs, thermal management techniques and suitable cavity configurations. This summary is completed by a presentation of new developments in the field, with a particular focus on the trends towards miniaturization.     

半导体激光器脉冲调制理论分析

本文用龙格-库塔法求解高斯脉冲调制下半导体激光器速率方程,对结果进行了分析。推出了较高偏置直流和高斯脉冲调制下计算激光脉冲延迟时间、脉冲宽度和最大调制码率的公式。给出了调制畸变的实验结果。     

Optimization of pumping mode for double-clad fiber lasers

A theoretical modeling of Yb-doped double-clad fiber lasers under various pumping modes including arbitrary numbers of end-pump and side-pump is introduced. Approximate analytic expressions of distributed lasers along the whole fiber are derived, and their accuracies are investigated. The effect of the pumping mode on the output performance of fiber lasers is discussed. The numerical results show that the approximate analytic solution is in excellent agreement with the exact numerical solution of the rate equations, the output power in the side-pump scheme is lower than that in end-pumping scheme, and more uniform distributions of laser and pump powers can be achieved by adopting the distributed pump mode and optimizing the arrangement of pump powers. However, further flattening the pump distribution by using more pump points can degrade the laser efficiency.     

可调谐半导体激光器研究及进展

可调谐半导体激光器是新一代密集波分复用系统以及全光网络中光子交换的关键光电子器件 ,它的运用使得光纤传输系统容量大大增加 ,灵活性和可扩展性大大增强 ,目前已经实现了宽波长范围的连续或准连续调谐 ,并有相应的产品投放市场 .文章介绍了各种基于不同谐振腔结构的可调谐激光器以及各自的调谐机理 ,对不同类型器件在制作以及实际应用中的优缺点进行了比较 .同时总结了国外可调谐半导体激光器的最新进展 ,并对我国可调谐半导体激光器的研制提出了相应的要求     

Terahertz frequency conversion in bulk and quantum-well semiconductor lasers

Simulation results of frequency conversion up to the terahertz region in semiconductor laser devices, both in bulk and quantum-well structures, are presented with a comparison of traveling wave amplifiers and Fabry—Perot oscillators. In both devices conversion gains greater than 0 dB can be achieved with a proper parameter choice. Interesting features of the conversion gain spectra for the oscillator-converter are pointed out with a discussion of the performances.     

Optical velocimeters for moving surfaces using gas and semiconductor lasers

A differential arrangement using a laser for the measurement of the velocity of moving surfaces is discussed. Configurations of optical velocimeters with diffraction beam-splitters are shown not to be critical on the wavelength stability of a semiconductor laser. Laser meters measuring the velocity and length of rolled stock have been built on the basis of the devices considered.     

Stable single frequency and single polarization DFB fiber lasers operated at 1053 nm

Stable single-frequency and single-polarization distributed-feedback (DFB) fiber laser was realized by giving a pressure on the phase shift region of the fiber grating. The output wavelength of the DFB fiber laser is 1053 nm. When the pump power of 980 nm laser diode is 100 and 254 mW, the output power can reach 8.3 and 37.1 mW and the polarization extinction ratio was 26 and 20 dB, respectively. After chopped by Acousto-optic modulator (0.3 Hz), the pulse peak value variance is 4.65%(peak to peak) and 1.098% (RMS) for 31 min.     

High‐brightness long‐wavelength semiconductor disk lasers

A review on the recent developments in the field of long‐wavelength (λ >1.2μm) high‐brightness optically‐pumped semiconductor disk lasers (OPSDLs) is presented. As thermal effects have such a crucial impact on the laser performance particular emphasis is given to modelling the thermal behaviour and optimisation of the heat‐sinking. Selected OPSDL devices, realized in different III‐V and IV‐VI semiconductor material systems, with corresponding emission wavelengths between 1.2 μm and 5.3 μm are presented. Specific applications in this broad spectral range are addressed and methods to obtain high output power are discussed in terms of the underlying material properties and device operating principles.     

Threshold analysis of fiber-coupler-combined fiber lasers

Threshold conditions of coherently combined fiber lasers, joint by fiber couplers (FCs), have been studied. After considering the phase change of a light wave crossing the fiber inside the FC, it has been shown that, at the two input ports of the coupler connecting with the amplifying fibers, the phase difference between the two incoming fields should be equal to −π/2 if the threshold gain of the compound system is to be minimized. Starting from these input ports, following the circulations of waves, threshold conditions can be established. Expressions for the output and leakage powers, and optimum coupler splitting ratio nullifying the leakage when constituent fiber lasers giving different free-running powers have been derived. And, the threshold gain reductions of individual lasers after being coherently combined have been predicted.     

Ultra-high repetition rate InAs/InP quantum dot mode-locked lasers

We have designed, grown and fabricated InAs/InP quantum dot (QD) waveguides as the gain materials of mode-locked lasers (MLLs). Passive InAs/InP QD MLLs based on single-section Fabry-Perot (F-P) cavities with repetition rates from 10 GHz to 100 GHz have been demonstrated in the C- and L-band. Femtosecond (fs) pulses with pulse duration of 295 fs have been achieved. The average output power is up to 50 mW at the room temperature of 18 °C. By using the external fiber mixed cavities fs pulse train with a repetition rate of 437 GHz has been generated. We have also discussed the working principles of the developed QD MLLs.     

基于互注入半导体激光器的混沌输出产生17.5 Gbit/s随机码

采用两个借助光纤连接的相互注入半导体激光器,实验获取了10 GHz超宽带混沌种子信号.通过8-bit模数转换器将混沌信号转换为二进制数据流,并进行进一步的逻辑异或处理和舍弃最高有效位操作,最终获得了能顺利通过美国国家标准与技术研究院(National Institute of Standard and Technology,简记为NIST)800-22标准测试以及Diehard测试,速率达17.5 Gbit/s的高速随机码. 关键词： 随机码 混沌激光 互注入半导体激光器     

InP基InGaAlAs/InGaAsSb应变量子阱激光器的子带跃迁计算

采用有效质量模型下的4×4 Luttinger-Kohn哈密顿量矩阵对In0.53Ga0.39Al0.08As/InxGa1-xAs0.9Sb0.1量子阱结构的能带进行了计算。求得了C1-HH1跃迁波长随In组分及阱宽的变化关系,并采用力学平衡模型计算了此应变材料体系在生长时的临界厚度。结果表明,在结构设计和材料生长中采用合适的材料组分和阱宽,在InP基InGaAlAs/InGaAsSb应变量子阱激光器中能够实现1.6～2.5 μm近中红外波段的激射波长。     

Applications of a dielectric coating to semiconductor lasers

Experimental studies and theoretical analyses on the effect of dielectric coatings on semiconductor laser performance are presented. It is demonstrated that the dielectric coating technique is a powerful means of controlling the laser threshold current, external quantum efficiency, maximum output power, longitudinal mode behaviour, lasing wavelength and spectral linewidth.     

面发射分布反馈半导体激光器

本文详细阐述了面发射分布反馈半导体激光器(SE-DFB-LD)的基本工作原理、结构设计及其工作性能,针对国内外研究最新进展与发展现状进行了总结和评述,并在此基础上,对面发射半导体激光器的研究工作和发展趋势做出了进一步的讨论和展望。随着面发射分布反馈半导体激光器各性能指标的不断优化提升和后期加工、装调技术的逐渐成熟,其将不断满足科学研究及工业、军事等实际应用领域对半导体激光器的需求,具有很大的发展潜力。