高速半导体激光器的设计

高速调制半导体激光器光源是高速光纤通信系统、相控阵雷达等的关键器件。本文分析了影响半导体激光器调制带宽的各种因素，系统地介绍了提高调制带宽的途径，并讨论了高速半导体激光器的典型结构和制造工艺。     

High speed performance of 2-D vertical-cavity laser diode arrays

We have fabricated and tested 10×10 independently addressable vertical-cavity surface-emitting laser diode arrays. Arrays with 55 μm active diameter devices show an average threshold current density of 590 A/cm² and an excellent homogeneity of the output characteristics over the full array size with maximum CW output powers of 12 mW. Broad area laser diodes with active diameters of 75 μm reach output powers of 18 mW for CW operation and 180 mW under pulsed conditions. Small-signal modulation bandwidths are beyond 10 and 8 GHz for the 55 and 75 μm devices, respectively     

高速宽温度范围无致冷DFB半导体激光器

报道了一种高性能的1.3μm波长的应变多量子阱分布反馈半导体激光器,它具有高的直接调制速率、宽的无致冷工作温度范围以及可靠性能好的特点.通过对激光器有源区、波导层以及DFB光栅结构的综合优化,所制作的激光器具有低的阈值电流以及高的量子效率,其室温直接调制速率达到16GHz,能实现-40℃～85℃范围内无致冷工作,其中值寿命超过200万小时.     

High light output-power single-longitudinal-mode semiconductor laser diodes

Issues related to realizing high light output-power single-longitudinal-mode InGaAsP/InP DFB LD's have been studied experimentally and theoretically. Asymmetry in the reflections as the front and rear facets of DFB cavity has been found to result in enhanced single-longitudinal-mode selectivity and higher light output power from the front facet. Single-longitudinal-mode CW light output power as high as 103 mW has been obtained in a 1.3-µm DFB-DC-PBH LD with facet reflectivities of 2 and 80-90 percent. Low internal quantum efficiency is pointed out to bean important problem for 1.5-µLD's.     

High light output-power single-longitudinal-mode semiconductor laser diodes

Issues related to realizing high light output-power single-longitudinal-mode InGaAsP/InP DFB LD's have been studied experimentally and theoretically. Asymmetry in the reflections as the front and rear facets of DFB cavity has been found to result in enhanced single-longitudinal-mode selectivity and higher light output power from the front facet. Single-longitudinal-mode CW light output power as high as 103 mW has been obtained in a 1.3-μm DFB-DC-PBH LD with facet reflectivities of 2 and 80-90 percent. Low internal quantum efficiency is pointed out to be an important problem for 1.5-μm LD's.     

半导体激光器驱动电路的研究与设计

半导体激光器又称激光二极管（LD）。半导体激光器驱动电路的设计对于激光器输出特性有重要影响,是决定半导体激光器系统稳定性的重要技术。激光二极管管芯温度的漂移以及其注入电流的变化都会对激光器出射频率产生变差,最终导致跳模或多模工作。为了确保半导体激光器的激光输出质量,本文研究设计了一款高性能的激光驱动电路,主要包括电源电路,恒流源电路,保护电路与及延时缓冲电路四部分。在Multisim软件中进行了电路仿真,并与实际电路中的结果图做了比较,最后应用日本某之名公司的光子强度检测器进行了实验测试与分析。实验结果表明该驱动电路设计满足要求,对后续研究具有重要意义。     

一种半导体激光器驱动电源的设计

根据半导体激光器的光功率与电流的关系,通过慢启动电路,纹波调零电路,功率稳恒电路等解决了使用中在工作温度范围内其输出功率不稳定的问题。本文设计的电路稳定度达到4×10-4。     

用于半导体激光器的高效率复合波导结构

提出了一种高电光转换效率的新型复合波导半导体激光器结构（Composite Waveguide LD,CWG LD）。该器件结构高的电光转换效率得益于其所采用的Al组分阶梯分布AlxGa1-xAs波导层。通过优化设计波导层电阻率分布及能带分布,CWG LD结构在保证输出光功率的同时,可以有效地降低器件串联电阻并提高电光转换效率。结合理论分析及计算机数值仿真软件,分析了复合波导提升器件电光转换效率的机理。经优化,在激光器条宽为6 m、腔长为1 000 m的情况下,波导层阶梯数为1时CWG LD结构可以获得最大的电光转换效率。研究结果表明:在注入电流为900 mA时,CWG LD结构的串联电阻由常规波导器件结构的3.51 降低为2.67 ,电光转换效率由54.7%提升至69.5%。     

Wavelength conversion and switching of high speed data signals using semiconductor laser amplifiers

Nonlinear gain dynamics in semiconductor laser amplifiers enables ultrafast signal processing. Wavelength conversion of up to 18 Gbit/s data signals is demonstrated. The switching characteristics are applied to the operation of an AND gate for 30 ps pulses.<>     

基于ZEMAX的半导体激光准直仿真设计

为了压缩905nm的半导体激光,以用于远程测距,采用几何光路原理,设计了由两个相互垂直的椭圆柱面透镜组成的准直系统,并在ZEMAX软件的非序列模式下实现仿真。半导体激光器快慢轴的初始发散角为30°和15°,经过柱面透镜后,半导体激光器两个方向的发散角都大大压缩;经准直后,激光束的快慢轴发散角分别为4.4mrad和3.6mrad,基本满足了远程测距的要求。结果表明,椭圆面柱透镜对半导体激光有很好的准直作用。     

基于直接调制和外调制的高速半导体激光光源

直接调制和外调制的半导体激光光源在现代光纤通信系统中有着重要的应用。首先介绍了应用于10 Gb/s接入网系统的直接调制AlGaInAs多量子阱DFB激光器。由于AlGaInAs量子阱的导带不连续性较大,因此基于该材料的半导体激光器具有良好的温度特性,其特征温度达到了88 K。同时,该直接调制激光器的3 dB小信号调制响应带宽超过15 GHz。随后介绍面向40 Gb/s干线传输系统的高速DFB激光器/EA调制器集成光源。该集成光源采用同一外延层集成方案,并采用Al2O3高速微波热沉进行了管芯级封装,在3 V反向偏压下获得大于13 dB的静态消光比,3 dB小信号调制带宽超过40 GHz。     

高速电路抖动性能的剖析与设计考虑

本文对SDH／SONET标准化协议中抖动性能做了比较详尽的描述,深入地剖析了几种容易混淆的有关抖动的概念。总结了一套现在较为流行的SDH／SONET抖动性能规范,并在相应的通信系统高速电路设计实践中,给出了一些如何减少电路抖动性能的切实可行的参考方法。     

Ultra-high speed semiconductor lasers

Recent progress on semiconductor lasers having a very high direct modulation bandwidth of beyond 10 GHz will be described. Issues related to application of these lasers in actual systems will be addressed. Possibilities of further extending the bandwidth of semiconductor lasers will be examined.     

阵列半导体激光器光束准直设计

根据变折射率介质对光束自动聚焦特点,并利用光线微分方程,设计了阵列变折射率介质棒准直阵列半导体激光束,计算机仿真表明,该准直系统能达到较为理想的准直效果,其准直结果可达3mrad～4mrad。     

High power semiconductor laser injection-locking at 1.3 μm

The injection-locking properties of a high power antireflection coated 1.3-μm slave laser subjected to relatively low injection powers from a distributed feedback (DFB) laser and from a tunable external cavity laser have been investigated. Narrow linewidth operation (~40 kHz) was demonstrated and the tuning range within two slave modes (~10 GHz) and over the gain profile (~40 nm) was investigated. In addition, the tracking properties of the slave laser for both frequency and phase modulated injected light was evaluated at 1 Gb/s, in which the fidelity was judged from bit-error-rate measurements. The maximum locked power under 1 Gb/s frequency modulation was about 145 mW, limited by the available master power; approximately 300 μW was injected into the slave     

High gain laser performance in alexandrite

Half-jouleQ-switched pulses of 20 ns duration have been obtained from an alexandrite laser operating on the high-gainR-line. Unique tandem pulsing, involving both a fixed and a tunable frequency pulse, is also observed.     

外腔半导体激光器的设计与高次谐波稳频

首先讨论了半导体激光器外腔结构参量对激光连续可调范围影响的理论计算方法,给出了Littrow结构外腔半导体激光器调谐范围的计算结果。然后介绍了半导体激光器外腔结构参量的具体设计,利用该设计得到了出射激光线宽小于1 MHz、连续可调谐范围可达3 GHz的780 nm波段外腔半导体激光器。接着讨论了利用腔外饱和吸收谱的三次谐波稳频方法对半导体激光器进行稳频,优化激光频率短期稳定度的方法。最后根据该优化方法设计出稳频系统对半导体激光器进行稳频,得到了稳定度达到10-12量级的半导体激光输出。     

High resolution laser LIDAR utilising two-section distributed feedback semiconductor laser as a coherent source

An air-spaced coherent LIDAR (light detection and ranging) employing a two-section distributed feedback (DFB) injection laser is demonstrated. The relative distance of a mirror target was detected with 0.1 mu m resolution. The absolute distance of a diffuse target was measured with 1 cm accuracy. These results indicate that semiconductor lasers developed for communication systems may be useful for sensing applications such as robotic vision, surface profiling and automated fabrication.<>