线性光放大器的宽带自发辐射噪声分析

建立含有垂直光场(VCL)的线性光放大器(LOAs)稳态仿真模型,考虑了宽带噪声特性、端面反射和纵向空间烧孔效应。计算了在不同输入信号功率和垂直腔分布布喇格反射器(DBR)反射率下总的输出ASE噪声功率、噪声系数(NF)、前向和后向传输的ASE噪声光子速率和噪声谱分布的变化。结果表明,与传统光放大器(SOAs)相比,在增益非饱和区,LOA有很好的噪声钳制作用,ASE噪声几乎不随信号功率的改变而变化。在增益饱和区,破坏了VCL的钳制作用,NF有所上升,但上升的速率小于SOA。提高DBR反射率,总的输出ASE噪声功率减小,但NF有所增大。     

放大自发辐射注入波长锁定法布里-珀罗激光器

波分复用无源光网络(WDM-PON)被认为是接入网的最终解决方案,基于放大自发辐射(ASE)注入波长锁定法布里-珀罗(F-P)激光器的WDM-PON由于其价格低廉和容易实现颜色无关操作而受到极大关注.实验研究了ASE注入波长锁定F-P激光器的ASE增益、边模抑制比(SMSR)和相对强度噪声(RIN)随F-P激光器注入电流和ASE注入功率的变化关系,理论模拟了ASE注入功率和增益一定时,F-P激光器注入电流随其前端面反射率的变化关系,并从实验上进行了验证.研究结果表明,当F-P激光器的注入电流为阈值电流的1.3～1.7倍时,能获得满足应用需要的相对强度噪声和边模抑制比.对于一定的ASE注入功率和输出功率,存在使注入电流最小的最佳前端面反射率.     

基于半导体光放大器的非相干光源抗反膜的优化设计

对半导体光放大器(SOA)放大的自发发射(ASE)谱进行了实验和理论研究,并且分析了SOA端面反射率对ASE谱的谱宽以及平坦度的影响.结果表明,不恰当的抗反膜会严重减小输出光谱的带宽;而在采用具有宽带材料增益谱的有源区基础上,结合抗反膜的优化设计,则可以获得既宽又平坦的非相干光源.     

基于半导体光放大器的非相干光源抗反膜的优化设计

对半导体光放大器(SOA)放大的自发发射(ASE)谱进行了实验和理论研究,并且分析了SOA端面反射率对ASE谱的谱宽以及平坦度的影响.结果表明,不恰当的抗反膜会严重减小输出光谱的带宽;而在采用具有宽带材料增益谱的有源区基础上,结合抗反膜的优化设计,则可以获得既宽又平坦的非相干光源.     

多级染料激光放大器中激光增益与放大自发辐射强度的理论研究

利用激光增益和放大自发辐射 (ASE)理论 ,对不同条件下的染料激光放大器的激光增益和ASE强度进行了数值计算。分析了当入射光强远小于和大于有效饱和光强时 ,激光增益和ASE强度与入射光相对强度的关系 ,讨论了在两种条件下ASE系数以及染料池端面反射系数对激光增益和ASE成分的影响。最后利用这些结果 ,对连续激光的多级染料放大系统的优化设计进行了讨论。     

单端耦合QD-SOA波长转换特性研究

通过光场传输方程和电子跃迁速率方程,采用细化分段方法,解常微分方程组的四阶龙格-库塔法和求解非线性方程组的牛顿法,建立了针对动态输入信号的仿真模型。对基于单端耦合QD-SOA的交叉增益调制(XGM)波长转换器转换光增益、啁啾特性与有源区长度、输入光信号功率、注入电流之间的关系进行了研究。结果表明增大泵浦光、减小探测光、增大注入电流都可以增加转换光啁啾特性,通过增加有源区长度和后端面反射率可以有效提高转换光增益,而光增益随注入电流变化不大。     

双电极半导体光放大器的放大自发辐射谱和增益特性的实验研究

设计并制作了双电极多量子阱半导体光放大器（SOA）,对其放大的自发辐射(ASE)谱和增益特性进行了测试和分析。结果表明,注入电流密度分布对多电极SOA的ASE谱和增益特性有非常大的影响。通过调节注入电流密度比,ASE谱的半高全宽、峰值波长、峰值功率以及增益特性能够得到很好的调控。     

基于RSOA再调技术40Gb/s传输系统研究

下一代接入网的发展趋势是WDM-PON(波分复用无源光网络),基于反射式半导体光放大器(RSOA)再调制的无色ONU技术降低WDM-PON成本与结构简化,因而具有较强的市场潜力。DPSK具有恒功率特性且抗干扰性能显著,常优先选作系统调制方式。在不断追求高速率、大容量的时代,单信道40Gb/s的光传输系统的研究就极具有意义。利用OptiSystem软件,仿真了基于RSOA的40Gb/s传输系统,分析了RSOA的增益特性与系统性能,最后验证了DPSK在基于RSOA的高速PON中应用的可行性。     

脉冲光纤放大器中放大自发辐射对光纤储能的影响

在高功率脉冲光纤放大器中,由于增益介质长,抽运功率高,脉冲间隔产生的放大自发辐射(ASE)严重限制了光纤储能能力和可提取能量的提高。针对低重复频率、强抽运的条件,以稳态速率方程为理论基础建立了脉冲放大器模型,利用理论模型对脉冲放大器性能进行了分析,着重讨论了不同的数值孔径、激光功率填充因子、端面反射率、纤芯直径、光纤长度、抽运功率等参数对放大自发辐射的影响。讨论了光纤的储能、增益和可提取能量等的变化规律,给出了掺镱光纤中最大可提取的单脉冲能量以及放大器增益。     

垂直腔半导体光放大器的增益特性数值分析

结合垂直腔半导体光放大器(VCSOAs) 的竖直微型腔结构带来的特性,在反射工作模 式情况下,分析了VCSOAs 的增益特性。通过数值求解激光器单模速率方程,给出了增益、饱和输出功率随泵浦光功率、出射腔面反射率的变化,分析了其功率动态范围。得出了提高腔面反射率能使增益得到增长,以及强泵浦光功率能起到平坦增益,增大增益的作用的结论。总结了VCSOAs 设计中的一些规律,以作实际应用中参考。     

Power scaling in quantum-well laser amplifiers

The effects of increasing excitation on the performance of quantum-well semiconductor laser amplifiers were investigated. Amplified spontaneous emission (ASE) and gain roll over at high injected carrier densities are two limitations to the power scaling of these devices. A Rigrod analysis was used to study the effects of these limitations on the gain, ratio of signal to ASE power, and efficiency for different values of injection current, facet reflectivity, and input laser intensity. Comparisons are made with an equivalent amplifier operating with a bulk semiconductor gain medium. This analysis suggests that quantum-well semiconductor amplifier performance improves with a double-pass configuration     

Facet reflectivity of a spot-size-converter integratedsemiconductor optical amplifier

Traveling-wave type semiconductor optical amplifiers (SOAs) integrated with a spot-size-converter (SSC) are extensively studied for improvement of coupling efficiency with single-mode fibers and for cost reduction in packaging. In this paper, the structural dependence of the SSC on effective facet reflectivity R_eff is investigated theoretically and experimentally. It is shown that, not only sufficient mode-conversion in the SSC region, but also the introduction of angled facets, are essential for reducing R_eff. A small gain ripple (less than 0.1 dB) in an amplified spontaneous emission (ASE) spectrum, fiber-to-fiber gain of 26 dB, and saturation output power of 7 dBm are observed for the fabricated SOA, which consists of a window length of 20 μm, facet angle of 7°, and anti-reflection coated facet of less than 1% reflectivity     

Amplified spontaneous emission effects in semiconductor laseramplifiers

The analysis presented provides a quantitative method for predicting semiconductor laser amplifier performance in the presence of ASE (amplified spontaneous emission). It indicates that in order to increase the fraction of pump power that contributes to the amplification of the input laser field relative to that spent in overcoming internal losses, an amplifier should operate at as high an excitation level as possible. This may mean operating an amplifier above its free-running oscillation threshold. A limitation to the maximum pump power is the increase in ASE. With too high an excitation, ASE dominates over the amplified input laser field, resulting in a quenching of the amplifier gain, efficiency and coherence. ASE effects may be mitigated by increasing the input laser intensity, decreasing the amplifier facet reflectivities, or, in some cases, tuning the master oscillator so that it is resonant with the amplifier. The analysis indicates that minimizing the facet reflectivity is the most effective way to circumvent ASE limitations to power scaling semiconductor laser amplifiers     

基于单端QD-SOA波长转换增益恢复特性研究

为了对单端量子点半导体光放大器（QD-SOA）全光波长转换器的增益恢复特性进行系统分析,采用分段法和4阶龙格-库塔法,利用单端QD-SOA的交叉增益调制效应的全光波长转换原理分别求解速率方程和光场方程,分析了注入电流、后端面反射率以及最大模式增益等变化时对单端QD-SOA全光波长转换器增益恢复时间的影响。结果表明,当增大注入电流和后端面反射率、减小最大模式增益时,均可以减小增益恢复时间,进而可以通过优化上述参量改善单端QD-SOA的增益恢复特性。     

Analytical model of a superluminescent diode

Using a set of traveling wave rate equations ,a superluminescent diode with a low facet reflectivity is studied .Analytical expressions of the distribu-tions of carrier density ,forward-and backward-propagation photon densities,and gain are obtained at different facet reflectivities.It is shown that the high nonuni-form carrier distribution is evident in the case of low facet reflectivity.The results can serve as useful guides in understanding emission mechanism of superlumi-nescent diodes.     

Analytical model of a superluminescent diode

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1.5 µm GaInAsP traveling-wave semiconductor laser amplifier

This paper presents a theoretical and experimental study in terms of small-signal gain, signal gain saturation, and noise characteristics of a 1.5 μm GaInAsP traveling-wave amplifier (TWA), realized through the application of SiOxfilm antireflection coatings. This TWA, having a residual facet reflectivity of 0.04 percent, exhibits a wide, flat signal gain spectrum and a saturation output power of +7 dBm at a 20 dB signal gain. The TWA also has a noise figure of 5.2 dB, which is the smallest value reported for semiconductor laser amplifiers. The experimental results are confirmed to be in good agreement with the theoretical predictions based on the multimode traveling-wave rate equations in conjunction with the photon statistic master equation analysis, which takes into account the amplifier material and device structural parameters. Signal gain undulation, saturation output power, and noise figure are also theoretically evaluated as functions of the facet reflectivity. The superior performance of the TWA demonstrates that the device is favorable for use in linear optical repeaters in fiber transmission systems.