光纤拉曼放大器噪声特性的研究

研究了拉曼放大器中的几种主要噪声,分析了噪声的来源及特点,给出了描述噪声的方程,并对其进行了数值计算,提出了改进噪声性能的方案。     

Adaptive-optics compensation in a Raman amplifier configuration

An experimental study of real-time adaptive compensation through a high-gain Raman amplifier is discussed. Atmospheric turbulence was simulated by selectively aberrated quartz plates designed to produce a turbulence-like phasefront distortion on a transmitted beacon. A 69-channel wavefront sensor measured the beacon's phasefront and commanded a deformable mirror to impose the conjugate phasefront on the Stokes seed to a high-gain, large-Fresnel-number Raman amplifier. After amplification, the output Stokes beam was made to retrace the path of the beacon back through the simulated turbulence. Measurements of the Stokes beam quality indicate a dramatic improvement to near-diffraction-limited performance. The experimental results are in good agreement with theory     

光纤拉曼放大器的最大拉曼增益特性

为了分析同向抽运与反向抽运光纤拉曼放大器的最大拉曼增益,基于耦合微分方程,采用理论推导的方法,根据不同抽运结构下信号光放大的不同实际情况定义并推导出同向抽运光纤拉曼放大器和反向抽运光纤拉曼放大器的最大拉曼增益公式。然后,详细分析了各个参数对两种抽运方式下光纤拉曼放大器的最大拉曼增益的影响。对两种抽运方式下相同参数引起的最大拉曼增益进行了比较。结果表明,同样的参数对同向抽运与反向抽运光纤拉曼放大器最大拉曼增益的影响有相同的地方,也有不同的地方。最后,将最大拉曼增益和常用的开关增益进行了比较。对光纤拉曼放大器的实验、成本估计和器件效率等研究有重要参考意义。     

Noise in free-electron laser amplifier

The equations of the free-electron laser amplifier are generalized to include higher order modes. The density and velocity fluctuations in the entering electron beam cause noise excitation in the amplifier. The electron beam fluctuations have been studied extensively, both theoretically and experimentally, in traveling wave tubes, and hence the well-tested formalism developed for this purpose is conveniently applied to the present problem. It is found that the fluctuations put a severe constraint on the achievable exponential gain in a proposed Raman-type free-electron laser operating at optical frequencies. A1/lambda^{3}scaling law is derived.     

Ultra-wide-band tellurite-based fiber Raman amplifier

We describe the first wide-band tellurite-based fiber Raman amplifier (T-FRA) for application to seamless ultra-large-capacity dense wavelength-division multiplexing (WDM) systems. First, we confirmed that the Raman scattering characteristics of the tellurite-based fiber has so large a gain coefficient and Stokes shift that we can achieve a wide-band tellurite-based fiber Raman amplifier with a shorter fiber length than when using silica-based fiber. Second, we investigated the small signal gain and the signal transmission characteristics for a high gain and high output power operation with a single-stage amplifier. Focusing on double Rayleigh scattering, we compared the high gain limit of tellurite- and silica-based fibers. We then studied the impact of nonlinear effects by measuring the bit error rate (BER) when using a two-stage amplifier with a high output power of 18.8 dBm in which we simultaneously amplified eight channel signals in the L-band located on the ITU 100-GHz grid. Finally, we designed a wide-band tellurite-based fiber Raman amplifier with a multiwavelength band pumping scheme. We constructed this amplifier with a tellurite-based fiber only 250 m in length pumped by four-wavelength-channel laser diodes, and it provided a 160-nm bandwidth with a gain of over 10 dB and a noise figure below 10 dB from 1490 to 1650 nm. We also measured the BER to confirm the transmission characteristics of the amplifier for single channel operation over the whole signal wavelength range of 160 nm. We thus confirmed that the amplifier could be employed in ultra-high-capacity WDM systems.     

Ultra-wideband tellurite-based Raman fibre amplifier

The first wideband tellurite-based Raman fibre amplifier is described. The amplifier provided a 160 mn bandwidth with a gain of over 10 dB and a noise figure below 10 dB from 1490 to 1650 nm with a tellurite-based fibre only 250 m in length pumped by 4 wavelength channel LDs     

MGC干线放大器噪声分析

前端与各分配点之间传输信号链路叫干线系统,它由电缆（或光缆〕和干线放大器（或光放大器〕组成。干线放大器是用来补偿电缆传输损耗,并均衡电缆衰减与V了成正比关系,使干线放大器的输出电平在其频带范围内保持一致。短距离干线可以采用MGC放大器,2km左右干线应采用A...     

Dynamic properties of double-pass discrete Raman amplifier with FBG-based all-optical gain clamping techniques

The authors propose and implement a discrete fiber Raman amplifier configured in double-pass scheme together with fiber Bragg grating (FBG)-based all-optical feedback. The double-pass amplifiers achieve more than a 30-dB net gain with affordable pump power and guarantee a large margin for gain clamping. The all-optical gain clamping is provided by the lasing wavelength inside the cavity caused by the high reflectivity FBG and wide-band reflector. A stable gain is obtained for large input signal dynamic range of 30 dB. The gain variation is kept below 0.17 dB and the noise figure is flattened at the same time. Also, the authors investigate the Raman gain and noise figure as a function of signal wavelength with the proposed gain clamping technique.     

Submicrosecond transient control for a forward-pumped Raman fiber amplifier

We propose and experimentally verify a new dynamic gain and tilt transient control technique for a multiwavelength forward-pumped Raman fiber amplifier. Using this technique, we demonstrate up to 7-dB static power excursion correction (to within 0.4 dB) and dynamic gain control with submicrosecond response.     

Pump interactions in a 100-nm bandwidth Raman amplifier

A design for a 100-nm bandwidth Raman amplifier is presented. The amplifier is pumped with eight, 130-mW lasers with wavelengths ranging from 1416 to 1502 nm. The peak-to-peak gain ripple is 1.1 dB. A new model was developed for this design that includes pump-to-pump and signal-to-signal interactions in addition to double Rayleigh scattering and amplified spontaneous emission. An understanding of the interactions among these various effects was essential to this design. These modeling results are based on measurements of the physical characteristics of the transmission fiber     

光纤喇曼放大器的发展与应用

首先介绍了光纤喇曼放大器的发展情况和原理结构,与掺铒光纤放大器相比,指出光纤喇曼放大器的优点,然后在三种不同环境下,对混合FRA/EDFA放大与EDFA单独放大这前后两种放大技术的QoS性能进行了比较,最后介绍了FRA在SDH、CATV、WDM和企业存储网络中的应用.     

Broadband high-gain dispersion compensating Raman amplifier

A Raman gain module compensating for both loss and dispersion of a 40 km standard telecommunication fibre span over the 1510-1565 nm band is reported. The optimised configuration ensures a low signal-spontaneous noise figure and negligible double-Rayleigh scattering noise. The high-gain margin of the amplifier makes it applicable for compensation of an 80 km span     

硅基喇曼放大器的研究进展

低成本的硅基光器件研究具有重要的意义,在硅中受激喇曼散射是实现光放大的有效方法.本文总结了硅波导中实现净增益和硅基喇曼放大器的发展过程和最新的研究进展,展现了硅基喇曼放大器以及硅基光子器件发展的光明前景.     

晶体拉曼放大器的理论解析

晶体拉曼放大器是获得高光束质量、高光谱纯度、高功率拉曼激光的重要途径。通过引入四个归一化综合参量,推导出了外腔拉曼放大器的归一化输运方程组。通过数值求解该输运方程组得到了描述拉曼放大器运转的一组普适理论曲线;分析了复合归一化变量对拉曼放大器性能的影响;研究了晶体拉曼放大器放大率、放大后拉曼脉冲形状、光-光转换效率等参量在泵浦脉冲功率密度、泵浦脉冲与被放大脉冲相对宽度、泵浦脉冲与被放大脉冲时间重叠性等条件的变化规律。用实验数据对归一化理论进行了验证,结果表明,理论结果与实验数据相吻合,证明了文中理论计算的正确性和可行性。     

Wide-band and gain-flattened hybrid fiber amplifier consisting ofan EDFA and a multiwavelength pumped Raman amplifier

A wide-band and finely gain-flattened hybrid fiber amplifier is realized. The seamless 3.0-, 1.3-, and 1.0-dB bandwidths of 80, 76, and 69 nm with relative gain-flatness of 11.3%, 4.7%, and 3.7%, respectively, are achieved for the first time using the amplifier. The amplifier consists of an erbium-doped fiber amplifier, which has a short fluoride-based erbium-doped fiber, a discrete Raman amplifier, which has two isolated Raman fibers pumped simultaneously at three wavelengths, and a small-peak-loss gain-equalizer. The amplifier also yields optical noise figures under 6.0 dB     

Raman fiber oscillator as optical amplifier

A Raman fiber oscillator used for optical amplification is demonstrated to have lower double Rayleigh scattering, transient spikes, cross-phase modulation, and higher saturation input threshold compared with a conventional discrete Raman amplifier at similar operating conditions. This could be a promising technology for deployment in practical systems.     

Noise performance of an overloaded maser amplifier

The noise output and noise factor F of a simplified model of a maser is studied as a function of the ratio g/G of small-signal gain g to actual gain G. The noise output drops rather sharply as g/G is increased. The noise factor, however, increases only very slowly from its value of F = 1 at g/G = 1 to F = 1 + ½ ln g for a totally overloaded maser (G = 1).     

光纤拉曼放大器中的后向自发拉曼散射噪声

提出了光纤拉曼放大器中的后向自发拉曼散射噪声的数学描述及其机理,并从实验上得到了后向自发拉曼散射噪声的光谱,后向拉曼散射光在泵浦的入射处有最大的光强,而在信号光出射处光强很小,这对光纤传输信号是有利的.在信号的输出端,自发拉曼散射的光强只与泵浦输入强度有关,而与增益光纤长度无关.     

OptiAmplifier下的光纤拉曼放大器仿真探究

本文利用Optiamplifier光放大器设计软件对拉曼放大器的泵浦光源种类、泵浦光源波长、泵源数目及功率的大小,及采用何种光纤等方面进行了仿真实验,最后从成本、实用角度出发采用三泵源实现了1530~1600nm放大带宽、平坦增益等性能指标。