Simulation of Multiwavelength Regeneration Based on QD Semiconductor Optical Amplifiers

In this letter, we examine the performance of a multiwavelength 2R regenerator based on the cross-gain modulation effect in quantum-dot semiconductor optical amplifiers. Extensive numerical simulations have been performed to investigate the device parameters and operating conditions of the proposed subsystem. All-optical regeneration of two input channels at 40 and 160 Gb/s are illustrated.     

基于两只半导体光放大器级联结构的多波长光纤激光器

通过数值模拟对两只半导体光放大器(SOA)级联结构的静态增益饱和特性进行了理论研究.在不考虑自发辐射的情况下,分析了注入电流对两只SOA级联结构增益的影响.实验上构建了一种基于两只SOA级联结构的多波长光纤激光器,观测并分析了半导体光放大器的驱动电流和增益带宽对多波长输出结果的影响.在室温下,获得了基本符合ITU-T标准100 GHz的27个波长以上的稳定多波长输出,各信道输出功率不平坦度小于±3 dB,线宽小于0.102 nm,信噪比大于25 dB,总输出功率为1.94 mW,并且与由单只SOA构成的多波长光纤激光器进行了对比.     

基于半导体光放大器交叉增益调制效应的主动锁模光纤激光器

提出一种腔内损耗小的基于半导体光放大器(SOA)交叉增益调制效应(XGM)的主动锁模光纤激光器结构。使用光环行器成功减小了激光器的腔内损耗,提高了激光器的输出功率。从理论上对有理数谐波锁模过程中腔内脉冲复合的物理机制进行了详细分析。利用有理数谐波锁模技术,在调制频率为10 GHz下,得到了重复频率为30 GHz的皮秒级光脉冲序列输出,其峰值功率约0.5 mW。由于半导体光放大器的宽增益谱与滤波器的较大可调谐范围,使得激光器输出可以在较大的波长可调谐范围内保持较大功率输出。成功实现了调制频率为20 GHz的谐波锁模短光脉冲输出,可调谐范围达40 nm,峰值功率大于0.65 mW。半导体光放大器和激光器的短腔长保证了激光器的长期稳定性。     

Colorless Operation of WDM-PON Employing Uncooled Spectrum-Sliced Reflective Semiconductor Optical Amplifiers

We demonstrate a low-cost wavelength-division-multiplexed passive optical network based on colorless uncooled spectrum-sliced reflective semiconductor optical amplifiers. In this network, we achieve bit-error rates of better than 10^-10 over 32 100-GHz-spaced channels from 0 degC to 60 degC in 155-Mb/s transmissions. The penalties due to dispersion effect and Rayleigh backscattering interference over 25 km are almost negligible. We also present colorless operations over 16-channel coverage in outdoor temperature range     

Properties of Optical Phase-Locked Loop Based on Four Wave Mixing in Semiconductor Laser Amplifiers

In this paper, the properties of the optical phase-locked loop(PLL) based on the four-wave mixing in the semiconductor laser amplifiers (SLAs) are discussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to the general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL system unstable because of its long loop delay. The influence on the output phase jitter of the optical PLL is also investigated.     

Quantum-Dot Semiconductor Optical Amplifiers

This paper reviews the recent progress of quantum-dot semiconductor optical amplifiers developed as ultrawideband polarization-insensitive high-power amplifiers, high-speed signal regenerators, and wideband wavelength converters. A semiconductor optical amplifier having a gain of > 25 dB, noise figure of < 5 dB, and 3-dB saturation output power of > 20 dBm, over the record widest bandwidth of 90 nm among all kinds of optical amplifiers, and also having a penalty-free output power of 23 dBm, the record highest among all the semiconductor optical amplifiers, was realized by using quantum dots. By utilizing isotropically shaped quantum dots, the TM gain, which is absent in the standard Stranski-Krastanow QDs, has been drastically enhanced, and nearly polarization-insensitive SOAs have been realized for the first time. With an ultrafast gain response unique to quantum dots, an optical regenerator having receiver-sensitivity improving capability of 4 dB at a BER of 10^-9 and operating speed of > 40 Gb/s has been successfully realized with an SOA chip. This performance achieved together with simplicity of structure suggests a potential for low-cost realization of regenerative transmission systems.     

Organic Semiconductor Optical Amplifiers

Organic semiconducting materials have been researched for novel optoelectronic devices due to their efficient light emission and high gain properties. Such devices range from organic light-emitting diodes and solar cells to lasers and amplifiers. This paper explores the research carried out on one of these devices: organic semiconductor amplifiers that have shown to give high gains of 20–40 dB in solution and solid state.      

Self-Stabilization of an Actively Mode-Locked Semiconductor-Based Fiber-Ring Laser for Ultralow Jitter

Noise characteristics are studied for a self-stabilized laser utilizing the interplay between the intracavity dispersion and the optical frequency shift. The noise suppression bandwidth of this scheme is from 0 to ~100 KHz and showed the reduction of residual timing jitter (integrated from 0.9 Hz to 1 MHz) from 2.2fs to 660 attosecond which represents, to our knowledge, the lowest timing jitter reported for an actively mode-locked laser     

High-Speed Mode-Locked Quantum-Dot Lasers and Optical Amplifiers

Recent results on GaAs-based high-speed mode-locked quantum-dot (QD) lasers and optical amplifiers with an operation wavelength centered at 1290 nm are reviewed and their complex dependence on device and operating parameters is discussed on the basis of experimental data obtained with integrated fiber-based QD device modules. Hybrid and passive mode locking of QD lasers with repetition frequencies between 5 and 80 GHz, sub-ps pulse widths, ultralow timing jitter down to 190 fs, high output peak power beyond 1 W, and suppression of Q-switching are reported, showing the large potential of this class of devices for O-band optical fiber applications. Results on cw and dynamical characterization of QD semiconductor optical amplifiers (SOAs) are presented. QD amplifiers exhibit a close-to-ideal noise figure of 4 dB and demonstrate multiwavelength amplification of three coarse wavelength division multiplexing (CWDM) wavelengths simultaneously. Modelling of QD polarization dependence shows that it should be possible to achieve polarization insensitive SOAs using vertically coupled QD stacks. Amplification of ultrafast 80 GHz optical combs and bit-error-free data signal amplification at 40 Gb/s with QD SOAs show the potential for their application in future 100 Gb Ethernet networks.     

Ultrafast All-Optical Processor Based on Quantum-Dot Semiconductor Optical Amplifiers

We have developed a theoretical model of an ultrafast all-optical signal processor based on the Mach–Zehnder interferometer with quantum—dot semiconductor optical amplifiers in both its arms. It is shown that such a processor under different conditions may realize wavelength conversion, xor logic operation, and optical 3R regeneration.      

Quantum-Dot Semiconductor Mode-Locked Lasers and Amplifiers at 40 GHz

Mode-locked lasers (MLLs) and semiconductor optical amplifiers (SOAs) based on quantum-dot (QD) gain material will impact the development of next-generation networks, such as the 100 Gb/s Ethernet. MLLs presently consisting of a monolithic two-section device already generate picosecond pulse trains at 40 GHz. Temperature dependence of pulsewidth for p-doped devices, a detailed chirp analysis that is a prerequisite for optical time-division multiplexing applications, and data transmission experiments are presented in this paper. QD SOAs show superior performance for linear amplification as well as nonlinear signal processing. Using cross-gain modulation for wavelength conversion, QD SOAs are shown to have a small signal bandwidth beyond 40 GHz under high-bias current injection. This makes QD SOAs much superior to conventional SOAs.      

基于半导体光放大器交叉偏振调制的波长转换分析

对半导体光放大器(SOA)中光偏振态发生改变的原因和交叉偏振调制型波长转换进行了探讨和分析.如果SOA具有偏振不灵敏增益,则波长转换效果与泵浦光的偏振态无关,而只与探测光的偏振态有关,而且当入射探测光的偏振与TE模振动方向成4 5°夹角时,交叉偏振调制的效果最明显.为了使转换效果更好,宜采用反相波长转换,SOA的自发辐射耦合因子β应该很小     

基于半导体光放大器交叉偏振调制的波长转换分析

对半导体光放大器(SOA)中光偏振态发生改变的原因和交叉偏振调制型波长转换进行了探讨和分析.如果SOA具有偏振不灵敏增益,则波长转换效果与泵浦光的偏振态无关,而只与探测光的偏振态有关,而且当入射探测光的偏振与TE模振动方向成45°夹角时,交叉偏振调制的效果最明显.为了使转换效果更好,宜采用反相波长转换,SOA的自发辐射耦合因子β应该很小.     

基于ANSYS的大功率半导体光放大器的热分析

功率型半导体光放大器（High-Power Semiconductor Optical Amplifier,以下简称HP-SOA）在长距离自由空间光通信等领域有着诱人的应用前景,1550nm波段高速、大功率光源的需求日益增加,促进了HP-SOA技术的发展。随着输出功率的提高,HP-SOA热耗散功率也随之增加,其热特性对器件性能影响日趋明显,需及时散热。因此散热问题的解决是一个很关键的技术,高效率的器件散热结构设计十分必要。文章利用ANSYS有限元分析软件对输出光功率26dBm的大功率SOA器件的温度场分布进行了模拟和优化设计,为SOA封装材料、工艺方案的选择提供了依据,并据此进行了封装实验。     

傅里叶域锁模扫频光相干层析系统仿真

建立了基于傅里叶域锁模(FDML)扫频光相干层析(OCT)系统的数值模型,通过对FDML光源中的组件进行建模,利用分步傅里叶法求解非线性薛定谔方程,研究了滤波器带宽对光源强度噪声与相位噪声的影响。在此基础上对OCT成像过程中的信号进行了数值仿真,研究了光源噪声和成像系统中的色散失配对点扩散函数及其滚降特性的影响,获得了扫频光源中元件特性与OCT系统性能的直接关系。     

A Tunable Multiwavelength Laser Employing a Semiconductor Optical Amplifier and an Opto-VLSI Processor

We propose and experimentally demonstrate a stable tunable multiwavelength laser employing a semiconductor optical amplifier (SOA) in conjunction with an opto-very-large-scale-integration (VLSI) processor. By uploading digital phase holograms onto the opto-VLSI processor, the amplified spontaneous emission of the SOA is arbitrarily sliced and injected back into the SOA to generate multiple lasing wavelengths with a linewidth of 0.5 nm. Experimental results demonstrate a tunable multiwavelength laser with a tuning range from 1528 to 1533 nm with power fluctuations of less than 0.5 dB.     

基于半导体光放大器的四波混频型全光波长转换器

本文报道了基于自行研制的半导体光放大器（SOA）的四波混频（FWM）型全光波长转换,采用环型腔掺铒光纤激光器（EDFL）作为泵浦源,实现了转换波长的连续可调。并就波长转换间距、光放大器的小信号增益和输入泵浦光功率对转换效率的影响进行了理论与实验分析,结果表明高的SOA增益和较大的输入泵浦光功率须利于转换效率的提高。     

RF Linewidth in Monolithic Passively Mode-Locked Semiconductor Laser

We have analyzed theoretically and experimentally the linewidth of the first harmonic of the photocurrent (radio-frequency (RF) linewidth) in monolithic passively mode-locked semiconductor lasers. Due to the absence of restoring force, the timing jitter is directly related to the RF linewidth, avoiding possible underestimations made with conventional methods of phase noise measurement. The RF linewidth is also analytically related to the pulse characteristics using Haus's model. The timing stability performance of a promising two-section quantum-dot laser is presented using RF linewidth measurements. Experimental evolution of the RF linewidth with power and pulsewidth is finally compared to the analytical expression.     

Optical FM Signal Amplification by Injection Locked and Resonant Type Semiconductor Laser Amplifiers

Optical FM signal amplification by semiconductor lasers is studied by emphasizing their bandwidth characteristics. The laser is operated either in an injection-locked mode or in a resonant amplification mode by keeping the drive current above or just below its threshold. The bandwidths of both amplifiers are evaluated by the reduction in modulation sidebands and are compared with the bandwidths measured statically by scanning the frequency of incident CW wave. The radic G = 25 GHz gain bandwidth product is obtained for both operation modes using a double heterostructure AlGaAs semiconductor laser. The bandwidth obtained in the above procedure is in good agreement with theoretical results.