全光自动增益箝制及其噪声优化研究

掺饵光纤放大器(EDFA)的自动增益箝制技术在WDM光网络中具有重要的作用，本丈采用BPF方案进行单波长自动增益箝制实验，并取得了满意的箝制效果。而后采用级联放大器的方法，增益箝制放大器的噪声特性得到进一步的优化。     

适合WDM网络动态增益均衡的全光增益锁定光纤放大器

在光纤放大器内部同时建立增益谱锁定与平坦机制，研制出适合ＷＤＭ网络应用的全光锁定高增益、大功率掺铒光纤放大器（ＥＤＦＡ）。在２３ｄＢ输入功率动态范围（－４０～－１７ｄＢｍ）内的增益箝制在３３ｄＢ，对应总输入功率为－１７ｄＢｍ的输出光功率为１６ｄＢｍ，锁定的－１ｄＢ增益带宽为１４ｎｍ（１５４７～１５６１ｎｍ）。     

EDFA增益箝制技术研究

介绍了EDFA增益箝制基本原理 ,对实现EDFA增益箝制的不同技术途径的箝制机理和结构进行了举例及扼要分析 ,给出了采用光纤光栅反射镜来实现EDFA全光增益箝制的仿真分析结果     

宽带铋基掺铒光纤放大器的增益箝制研究

应用于动态通信网络中的光放大器需要恒定的信号增益.为此,设计了一个基于环形激光腔结构的宽带铋基掺铒光纤放大器(Bi-EDFA),进行了宽带Bi-EDFA信号增益箝制特性的理论研究.结果表明:通过将放大器输出的一个前向放大自发辐射(ASE)噪声光反馈到输入端,可以实现对1.53 μm波段传输信号的增益箝制.环路损耗越小,...     

用增益箝制的EDFA实现8×2.5Gb/S波分复用系统的动态增益均衡

在掺铒光纤放大器（EDFA）内部将增益箝制在增益谱平坦区,研制成增益箝制的EDFA,实现了波分复用（WDM）8×2．5Gb／s×450kmG．652光纤级联放大传输系统的动态增益均衡,在传输信道数量改变的动态运行情况下,在误码率为10－12时,接收机灵敏度变化0．5dB。     

EDFA的增益控制及平坦技术研究

对EDFA的增益箝制和平坦的基本原理进行了介绍,对实现EDFA增益箝制和平坦的不同技术途径的机理和结构举例进行了扼要分析,给出了采用光纤光栅反射镜来实现EDFA全光增益箝制的仿真分析结果,指出了EDFA的增益控制及其平坦的技术发展方向。     

全光中继光纤传输系统中掺铒光纤放大器监控的研究

文章对全光中继光纤传输系统中掺铒光纤放大器(EDFA)作为提升放大器、线路放大器和前置放大器的监控问题进行了探讨,提出了利用相干光时域反射仪与本地控制单元监测和控制线路EDFA的增益与主备用倒换的方案,该方案可实现对上行和下行的线路EDFA的单端全光监测。     

掺铒光纤放大器的最佳光纤长度和增益特性

本文用三能级系统的速率方程建立了掺铒光纤放大器近似理论模型。在有激发态吸收时，各种泵浦波长下均获得了掺铒光纤的最佳长度。就增益随信号光及泵浦光光强的变化作了分析。通过对增益谱分析发现改变掺铒光纤长度可改变增益带宽，为掺铒光纤放大器在波分复用光纤通信系统中的应用提供了依据。     

EDFA的增益控制及平坦技术研究

对EDFA的增益箝制和平坦的基本原理进行了介绍，对实现EDFA增益箝制和平坦的不同技术途径的机理和结构举例进行了扼要分析，给出了采用光纤光栅反射镜来实现EDFA全光增益箝制的仿真分析结果，指出了EDFA的增益控制及其平坦的技术发展方向。     

两段级联内插差异损耗功率箝制掺铒光纤放大器

针对全光网中信道路径不同所引起的功率失衡问题 ,设计了一种利用商用光纤波分复用器实现两段级联内插差异损耗环的功率箝制掺铒光纤放大器 (EDFA)光路结构 ,并从理论和实验上研究了光路结构参数对放大器动态范围和噪声特性的影响。得出损耗插入最佳位置在 6 0 %附近 ,最佳插入损耗大小 5～ 8dB依抽运功率和光纤长度而定。所研制的功率箝制EDFA在信号波长 15 5 3nm处 ,动态范围大于 2 0dB ,动态范围内平均输出功率超过2 90 μW。     

1310-nm DBR-type MQW gain-clamped semiconductor optical amplifiers with AM-CATV-grade linearity

A 1310-nm gain clamped semiconductor optical amplifier with amplitude modulation CATV-grade linearity at an output power of 8 mW is demonstrated for the first time. The InGaAsP multiquantum-well laser amplifier is equipped with distributed Bragg reflectors at each end to supply the feedback necessary for gain clamping. The TE optical gain of 21.3 dB is measured to be constant within 0.1 dB up to 25-mW signal output power. Electrical signal distortion experiments are presented to demonstrate the linearity of the device.     

L-band erbium-doped fibre amplifier with clamped- and flattened-gain using FBG

A gain clamped long wavelength band erbium-doped fibre amplifier (L-band EDFA) based on a ring laser cavity is demonstrated using a fibre Bragg grating (FBG) at the output end of the amplifier. This new design provides a good gain clamping as well as a gain flattening. The gain is clamped at 16.9 dB with gain variation of less than 0.1 dB from input signal power of -40 to -18 dBm by setting the VOA=5 dB. Also, the amplifier has the flattest gain spectrum at VOA=5. The gain variation is less than 1.0 dB within the wavelength range from 1570 to 1600 nm. This gain clamped amplifier also can support a 12 channel WDM system.     

Optical Stabilization of Waveguide Amplifiers for WDM Ring Network With Recirculating Optical Power

We demonstrate an all-optical wavelength-division-multiplexing ring network immune to transients based on individual optically gain clamped waveguide amplifiers. The ring network is compared to a similar point-to-point configuration to quantify the effect of recirculating amplifier noise. In the results, we notice that the optical stabilization is strong enough to overcome the effect of accumulated amplifier noise over the entire transmission bandwidth, and no lasing or chaotic behavior occurs. In addition, due to the independent amplifier stabilization, the network has shown to be robust even in the case of failure and restoration. We prove that the obtained results are scalable with the amplifier number. All results are also applicable to fiber-based amplifiers.     

Gain clamping in two-stage L-band EDFA using a broadband FBG

A gain-clamped long wavelength band erbium-doped fiber amplifier (L-band EDFA) with an improved gain characteristic is demonstrated by simply adding a broadband conventional band (C-band) fiber Bragg grating (FBG) in a two-stage amplifier system. The FBG reflects backward C-band amplified spontaneous emission (ASE) from the second stage back into the system to clamp the gain. The gain is clamped at about 22.4 dB with a gain variation below 0.4 dB for input signal powers of -40 to -15 dBm. Compared with an unclamped amplifier of similar noise figure values, the small signal gain has improved by 2.4 dB due to the FBG which blocks the backward propagating ASE. At wavelengths from 1570 to 1600 nm, gain of the clamped amplifier varies from 19.4 to 26.7 dB. The corresponding noise figure varies by /spl plusmn/0.35 dB around 5 dB, which is not much different compared to that of the unclamped amplifier.     

Investigation of Transients in Single-Fiber Bidirectional Closed-Loop WDM Ring Network Using High-Power Gain Clamped EDWA

We investigate a transparent WDM ring network design immune to accumulated power transients where simultaneous bidirectional operation is achieved on a single fiber. This allows cost effectiveness, flexible traffic re-routing, and network operation. We demonstrate that add/drop of 15 out of 16 channels generate negligible $({≪ 0.15}~{hbox {dB}})$ power excursion on the surviving channel. These results have been obtained by using new high-gain erbium-doped waveguide amplifiers in an innovative gain-clamped configuration that allows bidirectional operation. The glass-on-silicon waveguide optical amplifiers are able to achieve a clamped flat gain of 15 dB on full C-band with up to 0-dBm input power. This is the highest output power ever reported for an erbium-doped waveguide amplifier. The amplifier can with almost identical performance operate with signals entering together from both ends or even from opposite ends. The gain properties of the amplifier are almost perfectly symmetric.      

On crosstalk and noise in an optical amplifier with gain clamping by vertical laser field

We have calculated the transient behavior and noise figure of a semiconductor optical amplifier (SOA) with the gain clamped by a vertical cavity laser (VCL). The characteristic behavior of the more conventional gain-clamped SOAs and SOAs with no gain-clamping is also studied and compared with the vertically gain-clamped amplifier. The calculations are based on a numerical stochastic rate equation model including several forward- and backward-propagating channels that are coupled to the vertical laser field through the active medium. The noise model takes into account the input noise, randomly amplified spontaneous emission, and random gain. Numerical simulations have been carried out to study the relaxation oscillations, crosstalk, and noise in a system with a strong input signal switched on and off while observing the output signals, VCL photon density, and carrier density. Results show that the VCL field captures most of the disturbances, in agreement with available experimental data.     

双包层EYDFA增益钳制效果的理论研究

基于速率方程的离散算法,实现了环形腔控制方案下,双包层EYDFA增益钳制的分析,研究了单、多信道情况下增益、噪声指数钳制的效果。结果表明：对于单信道EYDFA,随着衰减器衰减系数的增大,EYDFA的增益钳制范围增大,但信号增益钳制的幅度减小,且信号噪声指数增大;对于多信道EYDFA,只要激光谐振不被破坏,各信道增益都能得到有效钳制。