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。     

椭圆偏振光注入下VCSELs的偏振开关特性研究

本文基于自旋反转模型,理论研究了椭圆偏振光注入下垂直腔面发射激光器(VCSELs)的偏振开关特性。研究结果表明:在X偏振模占主导的VCSELs中,采用椭圆偏振光注入时,随着注入偏转角度θ的增大,VCSELs发生偏振开关所需的最小注入系数(ηin min)值将呈现减小的趋势;当注入偏转角度θ值固定时,随着注入光与VCSELs中心频率之间的频率失谐量从负值变化到正值,ηin min值总体呈现出先减小后增大的趋势,而ηin min的极小值出现在了注入光的频率靠近VCSELs的Y偏振模频率的附近。因此,改变注入偏转角度及注入频率失谐量均可以实现对VCSELs的偏振开关的有效调控。     

基于偏振测量的VCSEL激光器阈值行为研究

设计构建了垂直腔面发射激光器偏振测试系统,利用该测试系统研究了激光器不同偏振模式的阈值行为特点。激光器的输出光随着驱动电流的增大将会出现P偏振以及S偏振两种相互正交的偏振分量,并且两者具有不同的工作阈值;进一步依据测得的阈值点将激光器分为三个工作区域,通过对非偏振及偏振测试结果的比较分析得出:垂直腔面发射激光器的非偏振测量中观测到的工作阈值点体现的是P偏振分量的阈值点;激光器S偏振分量的阈值需要通过偏振测量才能明显观测到;P偏振与S偏振分量阈值电流之间的工作区域具有最好的线偏振度。本文的研究为垂直腔面发射激光器的未来研制测试工作和更好应用夯实了基础。     

单向耦合VCSEL偏振模的同步与编码

为了研究单向耦合垂直腔面发射激光器系统的混沌动力学及其在通信中的应用,采用数值仿真的方法,理论研究了两个单向耦合的垂直腔面发射激光器偏振模的同步特性,并通过对发射激光器偏振态相位的调制实现了该系统的编码。结果表明,主激光器和从激光器相应模式间可以获得高性能的同步,而且存在两个明显的同步区域——完全同步和注入锁定同步。加载的数字信息也可以在从激光器每个偏振分量中还原,这表明可以利用单模或多横模垂直腔面发射激光器进行多信道混沌通信。     

垂直腔面发射激光器的特性分析

垂直腔面发射激光器作为近凰年来光电子学领域研究的热点课题之一，要想很好的研究其应用价值，就必须了解它的各种特性。本文分析总结了垂直腔面发射激光器的阈值特性、光输出特性、模式特性、调制特性、偏振特性、远场特性以及热阻效应。     

500 GHz宽带双偏振光学频率梳的产生

提出了一种基于光电反馈产生500 GHz宽带双偏振光学频率梳的方案。该方案基于光电环路反馈1550 nm垂直腔面发射激光器,采用自旋反转模型,利用四阶龙格-库塔算法数值仿真研究了光电反馈参数对光学频率梳特性的影响。研究结果表明:通过光电反馈参数的调节可以控制1550 nm垂直腔面发射激光器输出的偏振状态,可实现Y偏振和X偏振光学频率梳的转换。此外,研究发现,在特定的光电反馈参数条件下,可获得Y偏振和X偏振同时存在的双偏振光学频率梳。并且在一定的光电反馈参数范围内,两个偏振方向的光学频率梳的光谱带宽都会随着光电反馈系数的增加而增大,相应的功率谱会随光电反馈系数的增加而变得越来越平坦。通过光电反馈系数及反馈时间的调节,获得了谱线平坦、梳线纯净、谱带超宽的光学频率梳,在10 dB幅度范围内Y偏振光学频率梳的光谱带宽可达250 GHz,X偏振光学频率梳的光谱带宽可达500 GHz。     

外部光反馈对980nm垂直腔面发射激光器振荡特性的影响

研究了外部光反馈对980nm垂直腔面发射激光器(VCSEL)振荡特性的影响.计算了垂直腔面发射激光器及边发射半导体激光器的光反馈灵敏因子.基于复合腔理论,分析了外部光反馈对垂直腔面发射激光器的阈值电流及微分量子效率等振荡特性参数的影响.实验结果表明,当反馈率为10%时,垂直腔面发射激光器的阈值电流由0.63A下降至0.59A,同时斜率效率和输出功率也有所下降.实验结果和理论分析符合得较好.     

外加电场下垂直腔面发射激光器的偏振转换电流

电光效应双折射可以控制垂直腔面发射激光器的偏振特性。本文计算了作用在垂直腔面发射激光器（VCSEL）的上面的分布格反射镜（DBR）上的外加电场产生的双折射,并在此基础上通过对自旋反转模型（SFM）的修正,得到面发射激光器在外加电场存在时的偏振转换电流。     

面向长距离通讯1550 nm垂直腔面发射激光器的研究

采用InP基衬底设计并制备了1550 nm垂直腔面发射激光器。采用混合镜面布拉格发射镜,其中顶部采用4.5对硅和二氧化硅的介电布拉格反射镜,同时采用隧道结的方式降低p层载流子吸收。制备出阈值电流在20 mA,室温直流下输出光功率为7 μW,激射波长为1554 nm,激射谱半高宽为3 nm的垂直腔面发射激光器。     

面向长距离通讯1550 nm垂直腔面发射激光器的研究（英文）

采用InP基衬底设计并制备了1550 nm垂直腔面发射激光器。采用混合镜面布拉格发射镜,其中顶部采用4.5对硅和二氧化硅的介电布拉格反射镜,同时采用隧道结的方式降低p层载流子吸收。制备出阈值电流在20 mA,室温直流下输出光功率为7μW,激射波长为1554 nm,激射谱半高宽为3 nm的垂直腔面发射激光器。     

Very Wide Hysteresis Cycles in 1550-nm VCSELs Subject to Orthogonal Optical Injection

A first experimental observation of three different types of frequency-induced polarization bistabilities in 1550-nm single transverse and polarization mode vertical-cavity surface-emitting lasers (VCSELs) subject to orthogonal optical injection is described. The hysteresis width of the bistable region that appears at longer wavelegth detunings increases as the injected power or the VCSEL current increases. Very large hysteresis widths are obtained. These widths are more than seven times larger than previously reported widths.      

Optical Injection-Induced Polarization Switching Dynamics in 1.5-$mu$m Wavelength Single-Mode Vertical-Cavity Surface-Emitting Lasers

We report the first experimental invetigation of the polarization-mode switching dynamics and injection-wavelength-dependent polarization-mode bistability of a 1.5-m wavelength single-mode vertical-cavity surface-emitting lasers (VCSELs) under external laser beam injection. An injection beam with polarization orthogonal to that of the stand-alone VCSEL caused polarization-mode instability and switching of the VCSEL output. By varying the optical injection detuning for fixed injection power observation was made of a novel form of polarization bistability which will have applications in a new type of all-optical flip-flop and signal processing scheme.     

Polarization-Controlled Surface Grating VCSELs Under Unpolarized and Polarized Optical Feedback

The polarization control of a surface grating vertical-cavity surface-emitting laser (VCSEL) and of a nominally identical standard VCSEL without a surface grating are compared for unpolarized and polarized optical feedback with different feedback levels in the long external cavity regime. While the polarization of the standard VCSEL is strongly influenced by isotropic feedback with a feedback level of just 1% and can even be controlled by polarized feedback, the surface grating VCSEL remains polarization-stable under isotropic feedback. Its polarization can only be disturbed by optical feedback polarized orthogonal to the polarization of the solitary surface grating VCSEL for feedback levels exceeding 18%.     

Mapping of the dynamics induced by orthogonal optical injection in vertical-cavity surface-emitting lasers

In this paper, the output characteristics of an oxide-confined AlGaAs-As quantum well vertical-cavity surface-emitting laser (VCSEL) under orthogonal optical injection are mapped as a function of the strength of the optical injection and the detuning between the injection frequency and the free-running frequency of the solitary laser, for a very large range of frequency detuning (from -82 to 89 GHz). The injection light is polarized orthogonally with respect to the solitary VCSEL output light. As the injection strength increases the VCSEL switches to the master laser polarization. Polarization switching is accompanied by a rich nonlinear dynamics, including limit cycle, wave mixing, subharmonic resonance and period doubling route to chaos. Polarization switching is found with but also without injection locking. Injection locking occurs with the slave fundamental transverse mode or, for large positive detunings, with the first-order transverse mode.     

Data transparent reconfigurable optical interconnections usingpolarization switching in VCSEL's induced by optical injection

We demonstrate a data transparent reconfigurable optical interconnection system based on optical injection controlled polarization switching in a master-slave vertical-cavity surface-emitting laser (VCSEL) configuration. A 140-Mb/s data stream generated by the slave VCSEL is redirected by an anisotropic diffractive optical element depending on the polarization state of the emitted light. The polarization of the slave laser is controlled by injecting an orthogonally polarized optical signal from a master laser. The current modulation of the master VCSEL and the subsequent polarization switching of the slave VCSEL occur at 40 MHz. In our setup, both the data rate and the optical interconnection reconfiguration rate are limited by the electronic drive circuitry and could in principle attain the gigahertz range     

高功率垂直腔底发射激光器的偏振特性

在垂直腔面发射激光器(VCSEL)作为显示光源的应用中,为了获得高功率的偏振激光,研究了980nm大口径底发射VCSEL的偏振特性。通过刻蚀矩形台面和矩形出光口径,制备矩形VCSEL。在连续条件下,出光口径为550μm×300μm的底发射矩形VCSEL最大输出功率为660mW,微分电阻为0.09Ω。实验中,矩形VCSEL在工作电流下,同时存在稳定的水平偏振光和竖直偏振光,并且沿着矩形长边出射的水平偏振光一直占据主导地位。而圆形VCSEL在水平和竖直方向的激射情况几乎相同。水平偏振光的激射光谱相对于竖直偏振光出现蓝移,并且用对称三层波导模型解释了蓝移现象。研究了矩形VCSEL的正交偏振比与矩形口径长宽比的关系。实验结果表明,矩形柱结构能够有效地稳定VCSEL的偏振方向,使大口径器件激射高功率的偏振激光。     

VCSEL polarization modulation for pulse-per-second clock signal transfer in optical frequency distribution systems

In this paper, a novel vertical cavity surface emitting laser (VCSEL) polarization modulation technique based on polarization switching due to thermal heating in a single transverse mode class 10 G VCSEL at 1 310 nm is demonstrated experimentally. The inherent orthogonal polarization switching of the VCSEL carrier with changing bias is exploited in the transmission of pulse-per-second (PPS) timing clock signal. Experimental results show that PPS pulse widths of 9.97 μs and 9.98 μs are measured for back-to-back analysis and over 3.21 km of G 652 urban fibre transmission, respectively. This work provides a novel alternative for adoption in optical frequency and time transfer applications.     

Transverse Mode Switching and Locking in Vertical-Cavity Surface-Emitting Lasers Subject to Orthogonal Optical Injection

In this paper, we report on theoretical and experimental investigation on polarization and transverse mode behavior of vertical-cavity surface-emitting lasers (VCSELs) under orthogonal optical injection as a function of the injection strength and of the detuning between the injection frequency and the free-running frequency of the solitary laser. As the injection strength increases the VCSEL switches to the master laser polarization. We find that the injection power necessary to obtain such polarization switching is minimum at two different values of the frequency detuning: the first one corresponds to the frequency splitting between the two linearly polarized fundamental transverse modes, and the second one appears at a larger positive frequency detuning, close to the frequency difference between the first-order and the fundamental transverse modes of the solitary VCSEL. We show theoretically that both the depth and the frequency corresponding to the second minimum increase when the relative losses between the two transverse modes decrease. Bistability of the polarization switching is obtained for the whole frequency detuning range. Such a bistability is found for the fundamental mode only or for both transverse modes, depending on the value of the detuning. The theoretical and experimental optical spectra are in good agreement showing that the first-order transverse mode appears locked to the external injection     

Investigation of polarization properties of VCSELs subject to optical feedback from an extremely short external cavity-part II: experiments

The effect of isotropic optical feedback from an extremely short external cavity on the emission properties of vertical-cavity surface-emitting lasers (VCSELs) is experimentally investigated. When changing the external cavity length a modulation of the total power and the wavelength emitted by the VCSEL is observed with a period of half the wavelength of operation of the device. When biasing the VCSEL around its solitary (without optical feedback) polarization switching (PS) current, PS between the two linearly polarized modes is observed by changing the external cavity length. This PS is found to occur through a hysteresis region. Our experimental results show a modulation of the PS currents and the hysteresis width when changing the external cavity length with a period of half the wavelength of operation. The experimental results are well explained by a two mode rate equation model.