表面等离子体调制的纳米孔径垂直腔面发射激光器

在普通850nm垂直腔面发射激光器基础上制备了表面等离子体调制的纳米孔径垂直腔面发射激光器.当小孔直径为200nm，周围光栅的周期为400nm时，在15mA驱动电流下最大输出光功率达到了0.3mW.介绍了该器件的制备工艺，并从实验和理论两方面分析了周期性光栅结构对光束的约束作用.     

Diode pumped 850 nm vertical-cavity surface-emitting laser

Very little, if any, has been published on optically pumped 850 nm vertical-cavity surface-emitting lasers (VCSELs), particularly for doped structures. This paper investigates GaAs-based VCSELs which have not been optimized for optical pumping work. Characterisation was carried out for both pulsed and continuous wave (CW). Pulsed operation causes a lower rise in temperature, thus postponing the onset of thermal rollover, and allowing the device to be operated at higher powers. A threshold of ∼160 kW/cm², and single mode output with incident power density of up to 225 kW/cm² were obtained. From the simulation work done, it has been observed that for optically pumped VCSELs, at higher pump density, there was faster turn on and higher output power, and that dilute nitride active material give better output performance compared to GaAs.     

Wavelength switching based on quantum-dot vertical-cavity surface-emitting laser

This study investigates, for the first time, static and dynamic wavelength switching characteristics of the 1.3 ??m quantum-dot vertical-cavity surface-emitting laser (QD VCSEL). The free-running QD VCSEL with ??1 and ??2 state innately is injected by a laser source with ??1 state. When the injection power exceeds the threshold power, the dominant state of the QD VCSEL changes from ??2 to ??1 state. Results of this study demonstrate that the wavelength switching based on a 1.3 ??m QD VCSEL has a simpler and more cost-effective configuration than those of previous systems.     

808nm大孔径垂直腔面发射激光器研究

垂直腔面发射激光器(VCSEL)中的载流子聚集效应使注入到有源区的工作电流只是通过边缘环形区域很窄的通道,激光功率密度分布不均匀;尤其当器件尺寸较大时,激射光斑呈现环状,环中间光强很弱.这是研制电抽运高功率大尺寸VCSEL尤为突出的技术难题.采用新型结构成功研制出808 nm波段高功率大孔径VCSEL,在注入电流为1A时,室温下连续输出功率达0.3 W. 关键词： 半导体激光器 垂直腔面发射激光器 高功率 大孔径     

Light flowers from coherent vertical-cavity surface-emitting laser arrays

Emission of symmetric flower-shaped light patterns from coherently locked hexagonal vertical-cavity semiconductor laser arrays is reported. The flower patterns preserve their shape while propagating in free space. The emission of these unique light distributions is explained as being due to the combined effects of thermal lensing and the loss patterns employed for array definition. A theoretical model for strongly coupled arrays matches the results.     

Stable single-mode vertical-cavity surface-emitting laser with a photoresistive aperture

It is numerically demonstrated that on-axis current channeling through the use of a photoactive layer or layers in vertical-cavity surface-emitting laser cavities counteracts hole burning and allows single-mode operation at high currents. The photoactive layers act as a variable-resistivity screen whose radial aperture is controlled by the light itself. Absorption of a small fraction of the light intensity suffices for significant on-axis current peaking with minimum efficiency loss and optical mode distortion.     

亚波长光栅调制的偏振稳定垂直腔面发射激光器研究

基于微光学技术设计得到了偏振稳定垂直腔面发射激光器结构, 将亚波长光栅结构集成在上分布布拉格反射镜表面, 光栅周期小于材料中光波长, 透射波和反射波中仅包含零级衍射, 避免了高级次衍射造成 的损耗. 集成光栅后不同偏振方向光阈值增益不同, 从而实现偏振控制. 实验结 果显示, 集成亚波长光栅结构后, 整个激射过程中偏振方向被固定在平行于光栅槽方向上, 获得偏振稳定激光输出, 正交偏振抑制比大于12 dB, 且阈值电流仅增大7.14%.     

长波长垂直腔面发射激光器研究

垂直腔面发射激光器（简称VCSEL）近年来受到了国内外科技界和企业界的高度关注，它在光通信领域具有潜在的应用．文章主要介绍了长波长垂直腔面发射激光器的发展历史、基本应用、器件结构、材料和制备工艺，最后分析了研制长波长VCSEL所遇到的问题及相应解决方法，并进行了展望．     

长波长垂直腔面发射激光器研究

垂直腔面发射激光器（简称VCSEL）近年来受到了国内外科技界和企业界的高度关注,它在光通信领域具有潜在的应用.文章主要介绍了长波长垂直腔面发射激光器的发展历史、基本应用、器件结构、材料和制备工艺,最后分析了研制长波长VCSEL所遇到的问题及相应解决方法,并进行了展望.     

Nonlinear spectroscopy with a vertical-cavity surface-emitting laser (VCSEL)

We have evaluated the suitability of a vertical-cavity surface-emitting laser diode (VCSEL) for spectroscopic applications. Despite its low output power it is possible to observe narrow resonances in a saturated absorption spectroscopy experiment on the cesium D ₂ transition at 852 nm, limited in width by the laser linewidth of several tens of MHz. High modulation efficiency of the VCSEL allows us to create modulation sidebands at 9.2 GHz frequency via direct modulation of the laser injection current. Using the carrier and either one of the sidebands coherent population trapping (CPT) resonances in a buffered cesium vapor can be prepared with linewidths below 130 Hz. With this very compact setup we have studied the dependence of CPT resonance position and linewidth as a function of optical detuning and find evidence of the influence of the excited state hyperfine structure. Received: 30 April 1999 / Revised version: 25 June 1999 / Published online: 30 November 1999     

1550 nm垂直腔面发射激光器的特征参量随温度的变化

在采用自旋反转模型分析垂直腔面发射激光器（VCSELs）动力学行为的过程中,为了正确预测VCSELs的动力学行为,需要准确给出自旋反转模型中光场衰减速率k、总反转载流子衰减速率γ_N、线性二向色性系数γ_a、线性双折射系数γ_p、自旋反转速率γ_s和线宽增强因子α这6个特征参量.本文对1550 nm VCSELs在自由运行和平行光注入下的输出特性进行实验分析,获取了这6个特征参量的值,并着重研究了当激光器温度在10.00–30.00 ℃范围内变化时,这6个特征参量呈现的变化趋势.研究结果表明,随着温度的逐渐升高,γ_p整体呈现逐渐增加的趋势,γ_a,γ_s,γ_N和k呈现复杂的变化趋势,而α则呈现逐渐减小的趋势.     

Propagation of spatially partially coherent emission from a vertical-cavity surface-emitting laser

Recently we observed a strong reduction of spatial coherence of the emission of large-aperture vertical-cavity surface-emitting lasers when they are driven by microsecond electrical pulses [Opt. Express 13, 9337 (2005)]. We study the influence of this partial spatial coherence on the propagation characteristics. The spatial decoherence manifests itself in the formation of a Gaussian far-field intensity distribution. We measure the transverse pulse profile from near to far field and see that the shape-invariant far-field regime starts after 140 microm in the pulsed regime as opposed to several centimeters in continuous wave operation. This value matches quantitatively calculations made with a novel partially coherent propagation model without any free fitting parameters.     

Design of a monolithic piezoelectrically actuated microelectromechanical tunable vertical-cavity surface-emitting laser

We report the design of a monolithic piezoelectrically actuated microelectromechanical tunable vertical-cavity surface-emitting laser (VCSEL). The main advantages of piezoelectric actuation compared with conventional capacitive techniques are improved wavelength control, reduced external and tilt losses, and lower power supply voltages. The details of the piezoelectric actuation scheme for a 980-nm VCSEL with a variable air gap are described. A tuning range of approximately 35 nm can theoretically be achieved with a 3-V power supply (2 x reduction from that of electrostatic actuation) by use of a 250-microm-long cantilever beam. The proposed actuation mechanism is insensitive to the pull-in phenomenon, therefore improving wavelength control and reducing threshold current. Drastic improvements in power efficiency make it ideal for low-power applications such as all-optical communication, chip-scale atomic clocks, and biological studies.     

基于外光注入互耦合垂直腔面发射激光器的混沌随机特性研究

通过在互耦合垂直腔面发射激光器(VCSELs)系统中增加外光注入, 建立了一种基于偏振可调光反馈VCSEL驱动互耦合VCSELs混沌系统模型, 分析了增加外光驱动对互耦合激光器随机特性的影响. 以不可预测度作为随机特性的评价指标, 采用信息论中的排列熵作为相应量化工具, 对系统输出混沌信号的不可预测性进行定量分析.数值研究了光强度、时延、偏振旋转角度以及驱动激光器与耦合激光器间的频率失谐对输出信号随机特性的影响.结果表明: 外光注入能够增大互耦合VCSELs输出混沌信号的排列熵, 即外光注入能够有效提高耦合系统的随机特性; 驱动激光器可调偏振片偏转角度调节到45° 附近, 注入强度适中, 满足耦合强度大于驱动激光器自反馈强度条件, 系统输出信号的排列熵较大; 在耦合时延与驱动激光器反馈时延不相等的同时, 增加驱动激光器与耦合激光器频率失谐, 外光注入互耦合VCSELs的随机特性能够得到进一步提高.     

垂直腔面发射激光器的饱和效应对慢光延时影响的研究

通过理论和实验研究了1550 nm量子阱垂直腔面发射激光器(QW-VCSEL) 的饱和效应对2.5 Gbps二进制伪随机序列(PRBS)慢光延时的影响. 利用Fabry-Perot腔边界条件结合光场分布, 推导出VCSEL中信号相位和延时表达式, 并结合速率方程, 建立信号功率与延时之间的联系. 实验研究了在VCSEL逐渐达到饱和状态过程中PRBS信号的延时时间和眼图的变化情况. 理论和实验结果表明, 由于受饱和效应的影响, 大功率信号在VCSEL中传输得到更好的信号质量, 但以牺牲延迟时间为代价. 为了获得较大的时延, 一方面需要控制信号功率, 其次还需要调节信号波长以追踪由于饱和效应导致的VCSEL峰值增益波长的变化轨迹. 关键词： 慢光延时 垂直腔面发射激光器 饱和效应     

Low power penalty tunable slow light using vertical-cavity surface-emitting laser amplifier

A tunable slow light of 2.5-Gb/s pseudo-random binary sequence signal using a 1550-nm vertical-cavity surface-emitting laser (VCSEL) is experimentally demonstrated. The influences of the bias current and the gain saturation on the slow light are investigated. With bias current increasing, tunable optical group delay up to 98 ps is obtained at room temperature. Demonstration of the time delay between 16 and 24 ps by signal intensity change is reported. Under an appropriate bias current, by tuning the input signal to track the peak gain wavelength of the VCSEL, slow light of a power penalty as low as 1 dB is achieved. With such a low power penalty, the VCSEL has a great potential application as a compact optical buffer.     

Micromechanical tunable vertical-cavity surface-emitting lasers

We report the study on a short wavelength-tunable vertical-cavity surface-emitting laser utilizing a monolithically integrated bridge tuning microelectromechanical system. A deformable-bridge top mirror suspended above an active region is utilized. Applied bridge-substrate bias produces an electrostatic force which reduces the spacing of air-gap and tunes the resonant wavelength toward a shorter wavelength (blue-shift). Good laser characteristics are obtained: such as continuous tuning ranges over 11 nm near 940 nm for 0--9 V tuning bias, the peak output power near 1 mW and the full-width-half-maximum limited to approximately 3.2--6.8 nm. A detailed simulation of the micromechanical and optical characteristics of these devices is performed, and the ratio of bridge displacement to wavelength shift has been found to be 3:1.     

Spatial distribution of the intensity noise of a vertical-cavity surface-emitting semiconductor laser

We studied anticorrelated quantum fluctuations between the TEM(00) and the TEM(01) transverse modes of a vertical-cavity surface-emitting semiconductor laser by measuring the transverse spatial distribution of the laser beam intensity noise. Our experimental results are found to be in good agreement with the predictions of a phenomenological model that accounts for quantum correlations between transverse modes in a light beam.     

Polarization instabilities in a multi-transverse-mode vertical-cavity surface-emitting laser with polarized optical feedback

We have experimentally studied polarization instabilities in the multi-transverse-mode regime of a vertical-cavity surface-emitting laser subject to polarized optical feedback. A dynamical regime that is similar to the transition from the so called low frequency fluctuation (LFF) to coherence collapse (CC) in the single-transverse-mode VCSEL is found and investigated. The role of higher order transverse modes is to increase the irregularity of the dynamics as shown experimentally and numerically.