垂直腔面发射激光器DBR的生长优化

基于能带理论和分布布拉格反射镜(DBR)的工作原理,分析了垂直腔面发射激光器(VCSEL)中DBR串联电阻较大的原因。采用组分渐变降低DBR结构中异质结界面处势垒,优化DBR的各层掺杂浓度,通过调控费米能级进一步降低DBR中的异质结势垒,从而有效降低DBR串联电阻。实验采用Al_(0.22)Ga_(0.78)As/Al_(0.9)Ga_(0.1)As作为生长DBR的两种材料,设计了DBR各层厚度,研究了AlGaAs材料的最佳生长温度,利用MOCVD外延技术完成了795nm VCSEL突变DBR与渐变DBR的生长。经过工艺制备,测得突变DBR和渐变DBR的电阻分别为6.6和5.3Ω,优化生长后的DBR电阻得到有效降低。     

用于空间光互连的850 nm VCSEL 4×4阵列的热场模拟

作为空间光互连系统的发射部分,垂直腔表面发射激光器(VCSEL)阵列的热特性直接影响到光互连系统的稳定性。建立了850nm VCSEL 4×4阵列的热场数学模型,并利用有限差分法求解热传导和热扩散方程,得出了在VCSEL单元工作电流为10mA时阵列的热场分布:VCSEL单元有源层温度约为50℃;整个阵列的温度仅为38.65℃。依据此结果制作了850nm 4×4光互连模块,其每通道稳定传输速率达到1Gbit/s。     

Influence of the carrier diffusion process on the transient response of vertical‐cavity surface‐emitting lasers

We investigate the transverse mode dynamics of weakly index‐guided vertical‐cavity surface‐emitting lasers (VCSEL). The turn‐on time of transverse modes are calculated by implementing a model for the VCSEL dynamics including diffusion and transport/capture phenomena. It takes into account the spatial dependence of the two carrier density profiles associated with the confined carriers in the quantum wells, and with the unconfined carriers in the barrier region. Devices of different aperture diameter under different excitation conditions are also studied. The model displays the correct turn‐on time dependence on the injection current density when compared with the experimental data available. We show that the turn‐on time of the modes increases when capture time increases and escape time decreases and also when diffusion increases. Copyright © 2002 John Wiley & Sons, Ltd.     

采用LPC55S69的CO激光气体检测无线传输系统的研制

CO气体作为一种还原剂在工业冶金等场景中广泛应用,对于CO的检测在工业生产、大气监测、中毒预警中是十分重要的.TDLAS技术能够高效准确地检测特定气体浓度,基于TDLAS技术的CO气体检测相较于传统检测方法优势明显.本设计采用LPC55S69作为主控,VCSEL激光器作为核心光源实现TDLAS的CO气体检测.随着检测环...     

10Gbit/s并行光收发模块在万兆以太网的应用

介绍了万兆以太网技术（10 gigabit ethernet technology) . 万兆以太网使用以太网结构实现10Gbit/s点对点传输，距离可达到40km，使以太网的应用从局域网扩展到城域网和广域网. 重点介绍了万兆以太网的功能结构、分层结构、物理传输介质和甚短距离（very short reach）网络传输的并行光传输系统在万兆以太网方面的应用.     

可变偏振光注入垂直腔面发射激光器的频率诱导偏振双稳

为了探索垂直腔面发射激光器偏振敏感的双稳演 化规律,进一步拓展其在光信息处理领域方面的应 用,本文采用自旋反转模型,数值研究了可变偏振光注入下1 550 nm垂直腔面发射激光器频率诱导偏振双 稳的特性。研究结果表明:在可变偏振角度光注入下,通过沿不同路径扫描频率失谐,垂直 腔面发射激光 器的两个正交偏振分量可在负失谐和正失谐区域产生频率诱导的偏振双稳。对于一确定的注 入强度,注入 光偏振角度的增加可导致负失谐区域的偏振双稳宽度逐渐扩展,而正失谐区域双稳宽度无明 显的变化;给 定适当的注入光角度,较大的注入强度更易于在负失谐区域展宽偏振双稳宽度。此外,在注 入光偏振角度 和注入强度均一定时,不同偏置电流情况下激光器偏振分量的频率诱导双稳宽度存在较大差 异,系统可以 通过合理地调节注入光偏振角以及偏置电流等参量实现对频率诱导偏振双稳的灵活控制。     

Optimum thickness of GaAs top layer in AlGaAs-based 850 nm VCSELs for 56 Gb/s PAM-4 applications

We studied the influence of GaAs top-layer thickness on the small-signal modulation response and 56 Gb/s four-level pulse-amplitude modulation eye quality of 850 nm vertical-cavity surface-emitting lasers (VCSELs). We considered the proportionality of the gain-saturation coefficient to the photon lifetime. The simulation results that employed the transfer-matrix method and laser rate equations led to the conclusion that the proportionality should be considered for proper explanation of the experimental results. From the obtained optical eyes, we could determine an optimum thickness of the GaAs top layer that rendered the best eye quality of VCSEL. We also compared two results: one result with a fixed gain-saturation coefficient and the other that considered the proportionality. The former result with the constant gain-saturation coefficient demonstrated a better eye quality and a wider optimum range of the GaAs top-layer thickness because the resultant higher damping reduced the relaxation oscillation.     

金属/p-GaAs界面态对接触电阻作用机理的研究

本文针对大功率垂直腔面发射激光器(vertical cavity surface emitting laser, VCSEL)阵列热阻大、出光不均匀的问题,研究p-GaAs层欧姆接触电阻值的作用机理,降低欧姆接触串联电阻的方法,以提高VCSEL阵列出射光功率的均匀性。基于3种常用欧姆接触金属Ti/Au、Ni/Au、Ti/Al/Ti/Au,研究各层金属厚度和金属组合对与p型欧姆接触电阻的作用规律;结合等离子体表面处理工艺,改变金属/p-GaAs界面态,研究界面态对欧姆接触电阻的影响规律。实验对比分析得到金属Ti/Au结构电极欧姆接触的比接触电阻率最低,为3.25×10^-4 Ω·cm²;基于金半接触势垒模型,通过表面等离子体处理,界面势垒可降低12.6%(0.269 2 eV降至0.235 3 eV),等离子体轰击功率可调控金半界面的势垒和态密度。     

高功率高光束质量980nm垂直腔底面发射激光器

报道了优化p面电极的高功率高光束质量980nm垂直腔底面发射激光器(VCSEL).采用数学模型对VCSEL的电流密度进行了模拟计算,发现电流密度分布由氧化孔直径和p面电极直径决定.确定氧化孔直径后,优化p面电极直径可以实现电流密度的均匀分布,抑制远场光斑中高阶边模的产生.将p面电极直径优化为580μm,制作的600μm的VCSEL远场发散角从30°减小到15°,优化器件的阈值电流和最高输出功率都略有增加.通过改进器件封装方式后,器件输出功率达到2.01W,激射波长为982.6nm.     

Optical broadcast and clock distribution for multi-chip-modules

In this letter, we report a new architecture for clock and broadcast distribution using optical interconnect components, such as vertical cavity surface emitting lasers (VCSEL) and pin photodiodes with benefits of diffractive optical elements (DOE) fan-out. A two-bit-large bus for broadcast or clock distribution demonstration is presented using collective wiring technologies and MCM hybridization process in a standard BGA package. Diffractive optical elements allow one to four distribution scene through an optical plate. Specific laser drivers for VCSELs and photodiode receiver are realized in complete CMOS 0.6 μm transmitter and receiver chips.