半导体光放大器自动增益控制的实验研究

从行波半导体光放大器（ＴＷ－ＳＬＡ）的增益特性出发。对光放大器的自动增益控制（ＡＧＣ）进行了研究，设计出一种全电子自动增益控制系统。自动增益控制系统对光放大器输出功率的波动有明显的改善作用，能够对由于工作温度，输入偏振态的变化而产生的光放大器增益变化进行自动控制，并对前级我国率的波动进行调节。     

半导体光放大器增益波动的研究

详细研究了行波半导体光放大器的增益波动特性，理论模型的建立舍弃了通常采用的载流子在光放大器中沿腔长方向均匀分布的假设。分析表明，光放大器增益波动的大小与器件端面反射率、自发发射因子以及入射光功率等因素有关。理论计算与实验结果得到了较好的吻合     

双折射对基于半导体光放大器的干涉型器件性能影响的模拟分析研究

分析了半导体光放大器中双折射对基于半导体光放大器的干涉型器件性能的影响，对基于半导体光放大器的马赫—曾德尔型波长转换器的理论计算表明，当半导体光放大器有双折射存在时，消光比不仅要比无双折射时的要低，而且还随着探测光的偏振态而改变，变化幅度可大于10dB。提出了减小双折射对干涉型器件影响的方案，并且分析了实现对增益和对相位变化同时具有偏振不灵敏的半导体光放大器的可能性。     

行波放大器增益饱和特性理论研究

以行波放大器速率方程为基础，采用传输矩阵方法，对行波放大器的增益饱和特性进行了理论研究，讨论了增益饱和特性对电流注入水平，腔面反射率的依赖关系，以及俄歇复合过程在行波放大器增益放大的作用，虽然俄歇复合过程可能提高饱和光强，但它会降低量子效率及非饱和增益，对器件的实际工作特性没有益处。     

直接扣除法测量半导体光放大器频率响应

在光电子器件散射参量定义的基础上建立了基于直接扣除法的半导体光放大器频率响应测量系统,测量中通过扣除激光器和探测器系统的频率响应,得到放大器固有的频率响应。对InGaAsP体材料行波腔半导体光放大器样品进行了测量,得到了放大器在不同注入光功率和不同偏置电流下的频率响应曲线。这些曲线很好地反应了半导体光放大器的增益饱和和噪声特性,进一步分析发现半导体光放大器对低频调制信号的放大能力弱于对高频信号的放大能力,分析认为其原因在于半导体光放大器的载流子寿命有限导致低频信号长时间消耗载流子时,载流子数量无法及时恢复,从而使得增益降低。     

1.55 μm偏振无关半导体光放大器腔面减反膜的研制

设计并制作了1.55 μm偏振无关半导体光放大器腔面TiO2/SiO2多层减反膜, 工艺过程中设计并使用了反射率实时监控装置, 得到了低于5×10－4的腔面剩余反射率. 器件测试结果表明, 管芯在250 mA电流下仍处于未激射状态, 表明减反膜有效抑制了芯片的激射. 半导体光放大器的自发辐射（ASE）谱波动在0.4 dB以下, 3 dB带宽大于52 nm, 半导体光放大器小信号增益近27 dB, 在1520~1580 nm波长范围内偏振灵敏度小于0.5 dB.     

970nm反射式垂直腔半导体光放大器的设计与制作

设计并制作了970 nm反射式垂直腔半导体光放大器(VCSOA),基于放大器结构,对放大器的噪声特性、增益和带宽特性进行了实验研究和理论分析.研究了反射式放大器的增益与垂直腔半导体激光器出光口径的关系,发现增益随着出光口径的增大而增大.对于970 nm的信号光,经过出光口径为400 μm的VCSOA后,最高获得了26 ...     

用楔形柱面光纤微透镜耦合的1.3μm SOA组件

运用激光模式耦合理论分析了半导体光放大器(SOA)与单模通信光纤的连接损耗,并设计制作了楔形柱面光纤微透镜用来实现两者的模斑匹配,有效地降低了器件的光耦合损耗.本文介绍了楔形柱面光纤微透镜耦合的1.3 μm半导体光放大器(SOA)组件及其制作方法.该组件的最大增益不小于14 dB,其偏振灵敏度小于1 dB,增益波动不大于0.5 dB.     

1.55μm AlGaInAs-InP偏振无关半导体光放大器及其温度特性研究

采用低压金属有机气相外延 (LP MOCVD)设备生长并制作了 1 5 5 μmAlGaInAs InP偏振无关半导体光放大器 ,有源区为 3周期的张应变量子阱结构 ,应变量为 0 35 % ;器件制作成脊型波导结构 ,并采用 7°斜腔结构以有效抑制腔面反射 ;经蒸镀减反膜后 ,半导体光放大器的自发辐射功率的波动小于 0 3dB ,3dB带宽为 5 0nm ,半导体光放大器小信号增益近 2 0dB ,带宽亦为 5 0nm .在 1 5 30— 1 5 80nm波长范围内偏振灵敏度小于 0 5dB ,峰值增益波长的饱和输出功率达 7dBm ;器件增益随温度的升高而减小 ,当器件工作温度从 2 5℃升高至 6 5℃时 ,增益降低小于 3dB .     

半导体激光放大器用于啁啾补偿的研究

详细分析了饱和工作状态下的行波半导体激光放大器的啁啾特性，从理论上证了实了利用其增益饱和所引起的自相位调制来对光源啁啾和光纤色散进行啁啾补偿的可行性，并且发现，对于不同脉宽的入射脉冲，光放大器均能发挥相位补偿的作用，这一特性可用来在长距离光纤传输系统中，对微弱啁光脉冲同时进行能量和相位的补偿。     

Polarization insensitive gain medium with hybrid strained quantum well

A polarization insensitive gain medium for optical amplifiers has been fabricated. The active layer is a structure with alternate tensile and compressive strain quantum wells. The waveguide is made into a taper with angled facets. In the experiment we found that the structure can suppress the lasing and decrease the polarization sensitivity. The gain imbalance between transverse electric and transverse magnetic gains is small, and 0.1 dB is obtained at a driving current of 100 mA. The full-width at half-maximum of amplified spontaneous emission is 40 nm within large current.     

Analysis of XGM-Based Wavelength-Conversion in SOAs Using Assist Light

Wavelength conversion based on the cross-gain modulation (XGM) in a traveling-wave type semiconductor optical amplifier (TW-SOA) using assist light is theoretically studied. Taking into account the spatial and temporal variations of carrier density along the SOA length, the dependency of the conversion response on the assist light conditions is simulated both for co- and counter-propagating assist light schemes.     

Polarized optical gain and polarization-narrowing of heavily oxidized porous silicon

We report on a polarization-sensitive optical gain in a blue-emitting Si/SiO(2) nanocrystalline system having a high degree of emission polarization memory. This system can show a positive optical gain or optical loss depending on the polarization state of the pump and emitted light. Under optical gain conditions, the degree of polarization of the amplified spontaneous emission increases with the pumping fluence. This effect has been attributed to an increase in the stimulated emission efficiency occurring for the linearly polarized emission component characterized by high photon occupation numbers (stimulating photon flux). This finding is independently supported by other experimental observations. The occurrence of polarization dependent stimulated emission strongly indicates the relevance of morphological effects in light emission from ultrasmall elongated silicon nanostructures.     

Properties of laser gain of Li:CdZnO/ZnMgO quantum well

The many-body optical gain in Li:CdZnO/MgZnO quantum well (QW) structures with spontaneous polarization and piezoelectric polarization, and ferroelectric dipole moment is investigated by using the non-Markovian gain model with many-body effects. The CdZnO/MgZnO QW structure with high Cd composition is found to have smaller optical gain because the strain-induced piezoelectric polarization and the spontaneous polarization in the well increase with the inclusion of Cd. The internal field is reduced due to the additional polarization by Li in the CdZnO/MgZnO QW structure. These results show that Li:CdZnO-based QW lasers are promising candidates for optoelectric applications in visible and UV regions.     

Theoretical Analysis of the Polarization- and Frequency-Dependent Gain for Fiber Optical Parametric Amplifier

Abstract

We develop the gain expression of fiber optical parametric amplifier with birefringent effect and loss. The simulations show that the optical parametric amplifiers' gain is frequency-dependent and polarization-dependent. If the signal polarization state goes along the fast axis, when the average half-difference of two pump frequencies is smaller, the gain flatness is better; if the signal polarization state goes along the slow axis, when half-difference of two pump frequencies is smaller, the gain flatness is worse, and the gain bandwidth becomes wider. We still find that the signal gain is different under the distinct signal polarization state.     

低双折射光纤中拉曼增益对光偏振态的影响

利用包含拉曼增益的耦合非线性薛定谔方程, 导出了斯托克斯参量表示的含拉曼增益的杜芬方程, 通过椭圆积分求出了杜芬方程的解析解, 重点分析了光波在低双折射光纤中传播时, 拉曼增益对其偏振态演化的影响结果表明当输入功率与运动常量满足一定关系时, 拉曼增益改变了光波传输时其偏振态演化周期.     

反射式光学电压互感器光路建模及偏振误差分析

光路系统的偏振误差极大地制约着准互易反射式光学电压互感器的准确度.借助琼斯矩阵,建立了分立光学器件及光纤熔接点的传输模型,推导出完整的电压互感器光路系统的数学模型.以此模型为基础,对电压互感器中的偏振误差进行了仿真分析.结果表明：光源偏振度、起偏器消光比及起偏器与相位调制器的对轴角度主要影响系统的检测灵敏度|法拉第准直旋光器的旋光角度、法拉第准直旋光器与BGO晶体的对轴角度误差是主要的偏振误差源,影响系统的测量准确度及稳定性|根据电子式电压互感器IEC60044-7 0.2S级标准,法拉第旋光角度误差应该小于1.6°,旋光器与BGO晶体对轴角度误差小于1.85°.该研究对准互易反射式光学电压互感器光路设计和误差抑制具有一定的参考价值和指导意义.     

Test of Lorentz invariance using optical cavities

This paper indroduces the precision test of Lorentz invariance using ultra-stable and low-loss optical cavities. The effective-field theory widely adopted in the analysis of experimental data has been reviewed. The sensitivity of the cavity resonant frequency to the Lorentz-violating tensor field is discussed in detail. In addition, the polarization of the optical field has been added to the model, and our analysis shows that the frequency shift due to Lorentz violation is not sensitive to the polarization of the optical field.      

一种新颖的偏振不敏感的基于半导体光放大器的四波混频光波长转换方法

提出和论述了一种新颖的偏振不敏感的基于半导体光放大器的四波混频光波长转换方法。基本思想是设计和采用一种全光学偏振态转换器 ,理论上能将随机偏振态的输入信号光转换为固定偏振方向且功率基本不变的线偏振光 ,利用它控制信号光的偏振态能够克服四波混频过程所固有的偏振敏感性。将这种方法与正交偏振双抽运方法结合起来 ,能较简单地实现偏振不敏感且具有近似常数转换效率的宽带四波混频光波长转换