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1.
We present modelling results investigating the carrier dynamics of an SOA composed of an inhomogeneous array of quantum dots
designed to produce broad gain amplification when optically pumped. We use a set of rate equations that describe the QDs inhomogeneity
and include an energy dependent occupation factor within each inhomogeneously broadened level and numerically solve them with
the propagation equation to investigate the amplification of optical signals in the waveguide. By treating the carrier filling
according to the quasi-equilibrium distribution, we are able to investigate the effect of band-filling (BFE) on the gain and
refractive index. The linewidth enhancement factor (α) is computed and analysed with respect to optical signal intensity as
well as electrical current density. 相似文献
2.
线宽增强因子是影响半导体激光器输出特性的一个重要参量,不同材料不同结构类型的半导体激光器的线宽增强因子有较大的差异.利用光注入半导体激光器的单模速率方程模型,数值研究了线宽增强因子对外光注入半导体激光器的非线性单周期振荡特性的影响.结果表明:外光注入半导体激光器的动态特性对线宽增强因子的变化极为敏感,随着线宽增强因子的增加,在负失谐注入范围内单周期振荡区域显著增大,同时注入锁定的稳态输出被大大抑制.分析了线宽增强因子对非线性单周期振荡光谱特性和振荡频率的影响,结果表明:随着半导体激光器线宽增强因子的增大,单周期振荡的频率越大|当线宽增强因子不变时,单周期振荡的频率随注入光强度和频率失谐的增加而增加. 相似文献
3.
基于光反馈半导体激光器产生的宽带混沌信号作为物理熵源生成物理随机数已得到广泛研究.线宽增强因子的存在会导致半导体激光器出现大量不稳定动态特性,因此,本文着重研究半导体激光器的线宽增强因子对生成随机数性能的影响.数值仿真结果表明:随着线宽增强因子的增加,光反馈半导体激光器输出混沌信号的延时峰值逐渐减小、最大李雅普诺夫指数逐渐增大.基于不同线宽增强因子下产生的混沌信号提取随机数,并利用NIST SP 800-22软件对生成随机数的性能进行测试.测试结果表明,选取线宽增强因子较大的半导体激光器产生混沌信号作为物理熵源易于生成性能良好的随机数. 相似文献
4.
对半导体光放大器有源区中的非简并四波混频(NDFWM)过程的几种主要物理机制进行了理论分析与数值计算.由载流子速率方程、密度矩阵方程及非线性波动方程出发,分别考虑产生NDFWM效应的三个主要的物理过程:载流子浓度调制(CDP),载流子热效应(CH)及光谱烧孔效应(SHB),理论推导得其各自相应的非线性耦合波方程组,并将三种物理机制对NDFWM的贡献进行了比较,同时还讨论了线宽增强因子对NDFWM的转换效率的影响.
关键词: 相似文献
5.
We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a self-gain modulated SOA are measured and, from these, values of carrier lifetimes and linewidth enhancement factors are determined for various SOA input optical powers. 相似文献
6.
Four wave mixing analysis is stated for quantum dot semiconductor optical amplifiers (QD SOAs) using the propagation equations (including nonlinear propagation contribution) coupled with the QD rate equations under the saturation assumption. Long wavelength III-nitride InN and AIInN QD SOAs are simulated. Asymmetric behavior due to linewidth enhancement factor is assigned. P-doping increases efficiency. Lossless efficiency for InAlN QDs for longer radii is obtained. Carrier heating is shown to have a considerable effect and a detuning dependence is expected at most cases. InN QD SOAs shown to have higher efficiency. 相似文献
7.
本文从解光场方程和载流子浓度以及光子密度速率方程的自洽解出发,研究条形DH半导体激光器高频调制下光输出的频率锁定、准周期、分岔和混沌现象。结果表明,不稳定的条形半导体激光器可能出现混沌的光输出;其通向混沌的途径是准周期到混沌。所得结果与实验符合得很好,并澄清了当前理论中的混乱之处。 相似文献
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10.
L.J. Van Ruyven 《Journal of luminescence》1984,29(2):123-161
The improved technology of compound semiconductor heterojunction preparation has resulted in very reliable CW, room temperature diode lasers for optical information read-out grown on p-type substrates on the one hand and very abrupt double heterojunction diode lasers based on quantum effects on the other hand. The influence of quantization effects on the emission wavelength, the threshold current and its temperature dependence are discussed. A distinction has been made between quantization due to strong magnetic fields giving rise to a one-dimensional electron gas (quantum wire) and quantization resulting from electrostatic and/or compositional changes (quantum well). The double heterojunction as a test structure to study carrier scattering into quantum wells, the phonon participation in the hot carrier relaxation process and optical flux guiding in graded heterojunctions have been emphasized. 相似文献
11.
The linewidth enhancement factor (α) of inhomogenously broadened InAs/GaAs quantum dot (QD) lasers is studied taking into account the effect of the multi-discrete QD energy levels for both electrons and holes. The effect of size-fluctuation and the separation between the energy states on α for different applied bias is studied. Very small value of α (∼0.3) is obtained at high-applied bias. This value is smaller than the linewidth enhancement factor in quantum well lasers. An empirical formula for the linewidth enhancement factor is also derived. 相似文献
12.
Radhakrishnan Nagarajan 《Optical and Quantum Electronics》1994,26(7):S647-S666
Early theoretical predictions and later experimental work have shown that lasers with quantum well active areas have enhanced differential gain over bulk lasers. The resonance frequency in a semiconductor laser is proportional to the square root of the differential gain. The resonance frequency is directly related to the modulation bandwidth, and the enhancement in the intrinsic differential gain led to theoretical predictions of increased modulation bandwidth in quantum well lasers. This enhancement in the modulation bandwidth proved to be elusive initially, and later it was realized that other factors, namely carrier transport effects, played a more dominant role in the high-speed properties of quantum well lasers. Carrier transport effects, in addition to bandfilling, affect a wide range of static and dynamic properties of the quantum well lasers. This paper will present an overview of our present understanding of the carrier transport processes and their effects in quantum well lasers. 相似文献
13.
Surface plasmons are of particular interest recently as their performance is approaching the enhancement of light emission efficiencies, after synthesized close to the vicinity of solid state materials, i.e., semiconductor structure. As other scientific works have been proposed to improve the light-emitting efficiency, such as the use of resonant cavities, photon recycling, and thin-light emitting layers with periodic surface texturing, surface plasmon possesses a promising way to the light enhancement, due to the energy coupling effect between the emitted photons from the semiconductor and the metallic nanoparticles fabricated by nanotechnology. The usual pathway of plasmon enhanced light emitting devices is the use of Ag/Au nanoparticles coating the surface of semiconductor quantum dot (QD) or quantum well (QW) structures. However, apart from efforts to extract as much light as possible from single-driven surface plasmon-QD/QW, it is possible to enhance the light emission rate with double optical-excitations. This approach is based on the quantum interference between the external lasers and the localized quantum light, and promised to stimulate the development of plasmon-enhanced optical sensors. In this review, we describe the quantum properties of light propagation in hybrid nanoparticle and semiconductor materials, i.e., quantum dot or nanomechanical resonator coupled to Ag/Au nanoparticles, driven by two optical fields. Distinct with single excitation, plasmon-assisted complex driven by two optical fields, exhibit specific quantum interference characteristics that can be used as sensitive all-optical devices, such as the slow light switch, nonlinear optical Kerr modulator, and ultra-sensitive mass sensing. We summarize the recent advances of light propagation in surface plasmon-enhanced quantum dot devices, driven by two optical fields, which would stimulate the development of novel optical materials, deeper theoretical insights, innovative new devices, and plasmonic applications with potential for significant technological and societal impact. 相似文献
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Enhanced locking region in injection-locked two-section lasers 总被引:1,自引:0,他引:1
In this Letter, we investigate the criteria for achieving an enhanced stable locking region in the parameter space of injected field Einj and frequency detuning ω in two-section semiconductor lasers subject to optical injection. Using the rate equations, a stability analysis is performed and the conditions for an enhanced locking region are deduced from the requirement for the average linewidth enhancement factor appearing in the locking-bandwidth equation to be close to zero. We calculate a stability map for an injection-locked two-section laser with an almost-symmetrical locking region that is greatly enhanced compared to a single-section injection-locked laser with identical material and control parameters. 相似文献
16.
分析了单量子阱(SQW)、多量子阱(MQW)和分别限制异质结构量子阱(SCH-SQW)半导体激光器的阈值.求出了表示光增益随注入载流子密度变化的方程.利用这个结果,得到了上述三种量子阱半导体激光器的阈值电流密度的表达式. 相似文献
17.
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γN、线性二向色性系数γa、线性双折射系数γp、自旋反转速率γs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,γp整体呈现逐渐增加的趋势,γa,γs,γN和k呈现复杂的变化趋势,而α则呈现逐渐减小的趋势. 相似文献
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The sensitivity of quantum-dot semiconductor lasers to optical feedback is analyzed with a Lang-Kobayashi approach applied to a standard quantum-dot laser model. The carriers are injected into a quantum well and are captured by, or escape from, the quantum dots through either carrier-carrier or phonon-carrier interaction. Because of Pauli blocking, the capture rate into the dots depends on the carrier occupancy level in the dots. Here we show that different carrier capture dynamics lead to a strong modification of the damping of the relaxation oscillations. Regions of increased damping display reduced sensitivity to optical feedback even for a relatively large alpha factor. 相似文献
20.
Misuzu Sagawa 《Optical Review》1996,3(6):518-527
180° mode phased array lasers with multiple stripes were systematically investigated for high-power, single lateral mode operation. Phased array lasers with a conventional loss guide structure were fabricated for 180° mode operation because the structure allowed the threshold gain of 180° mode to become smallest by introducing optical loss between stripes and outside the stripe region. It showed complete single lateral mode operation under pulsed condition. However, under continuous wave operation, phase-uncoupling occurred at the edge emitters as a result of the temperature distribution inside the stripe region. This was confirmed both experimentally and theoretically. To minimise the temperature distribution, dummy stripes were introduced outside the stripe region. The current in the dummy stripes did not cause lasing, but did increase the temperature of the edge stripes, which improved the thermal distribution inside the stripe region. As a result, complete single lateral 180° mode operation under continuous wave operation was attained. 相似文献