光纤非线性效应对10 Gb/s波分复用色散补偿系统的限制

对信道间距为１００ＧＨｚ的８倍１０Ｇｂ／ｓ波分复用色散补偿系统进行了计算机仿真,分析了光纤的色散和自相位调制（ＳＰＭ）、互相位调制（ＸＰＭ）、四波混频（ＦＷＭ）等非线性效应在具有级联光放大器系统中的作用。四种色散补偿方案是：ＳＭＦ（常规单模光纤）＋ＤＣＦ１（色散斜率为正的色散补偿光纤）、ＳＭＦ＋ＤＣＦ２（色散斜率为负的色散补偿光纤）、ＴＷ１（色散为正的非零色散光纤）＋ＴＷ２（色散为负的非零色散光纤     

分立式色散补偿拉曼放大器增益特性及非线性现象研究

分立式色散补偿拉曼放大器具有兼顾色散补偿和信号放大的特点，在通信系统中展现出广阔的应用前景.对反向抽运的C波段色散补偿分立式拉曼放大器的增益谱形状，增益饱和及受激布里渊散射等特性进行了较为详细的实验研究. 关键词： 分立式色散补偿拉曼放大器 增益饱和 受激布里渊散射 斯托克斯波     

混合型光纤喇曼放大器增益和带宽的研究

混合型色散补偿光纤喇曼放大器由普通G652光纤和色散补偿光纤(DCF)组成,包括:DCF +G652、G652 +DCF和 G652+DCF +G652。讨论了它们的工作原理.使用FRA-OptiAmplifier4.0软件对其进行了优化设计,最佳结构为G652 +DCF.它可补偿光纤网络的色散,扩展通信波长范围.1427 nm的喇曼激光器作为激发源,用Q8384光谱分析仪测量了光纤的喇曼增益谱和小信号放大光谱,混合型色散补偿光纤喇曼放大器在S带和C带具有88 nm的增益带宽,这增加了光纤通信网络的传输通道.     

PSA高速常规单模光纤通信系统的传输性能及其与EDFA系统的比较

本文采用计算机系统仿真的方法研究了应用相敏光放大器(PSA)并附加DCF色散补偿的高速常规单模光纤通信系统的传输性能,并和相同速率的掺铒光纤放大器(EDFA)系统进行了比较.研究着重于传输速率、放大器间距对系统码间干扰限制距离的影响.结果表明PSA系统比EDFA系统更适合于高速率传输并具有更长的传输距离.而且,对PSA系统,在放大器增益正好补偿光纤损耗的条件下,存在一相应于最大码间干扰限制距离的最佳放大器间距.     

宽带光纤拉曼放大器的优化设计与分析

基于拉曼放大器的功率耦合方程 ,采用遗传算法和全局收敛的布雷登方法 ,提出一种优化设计不同形式反向抽运宽带光纤拉曼放大器的自动配置算法。该算法的特点是计算速度快 ,收敛性好 ,适应面广。通过对具有不同增益要求的分立式、单光纤分布式以及不同结构的色散管理式宽带拉曼放大器设计表明 :在 10THz的增益带宽内 ,放大器的增益平坦度均优于± 0 .6dB ,表明了该算法的可行性。通过对由标准单模光纤和色散补偿光纤构成的组合放大单元与色散管理光纤级链组成的放大单元的比较 ,表明色散管理式拉曼放大器具有潜在的应用价值。     

Multi-wavelength hybrid gain fiber ring laser based on Raman and erbium-doped fiber

A stable and uniform multi-wavelength fiber laser based on the hybrid gain of a dispersion compensating fiber as the Raman gain medium and an erbium-doped fiber (EDF) is introduced. The gain competition effects in the fiber Raman amplification (FRA) and EDF amplification are analyzed and compared experimentaUy. The FRA gain mechanism can suppress the gain competition effectively and make the present multi-wavelength laser stable at room temperature. The hybrid gain medium can also increase the lasing bandwidth compared with a pure EDF laser, and improve the power conversion efficiency compared with a pure fiber Raman laser.     

A Dispersion Flattening Dispersion Compensating Fiber Design for Broadband Dispersion Compensation

An efficient dispersion compensating fiber (DCF) design is proposed based on a coaxial fiber structure, which provides dispersion compensation over a broad wavelength region matching that of an erbium-doped fiber amplifier gain spectrum. The design can provide dispersion coefficient that is nearly twice those of existing DCF designs. Due to the basic nature of the dispersion curve of this design, the total link dispersion cannot only be compensated but also can be flattened.     

A Dispersion Flattening Dispersion Compensating Fiber Design for Broadband Dispersion Compensation

An efficient dispersion compensating fiber (DCF) design is proposed based on a coaxial fiber structure, which provides dispersion compensation over a broad wavelength region matching that of an erbium-doped fiber amplifier gain spectrum. The design can provide dispersion coefficient that is nearly twice those of existing DCF designs. Due to the basic nature of the dispersion curve of this design, the total link dispersion cannot only be compensated but also can be flattened.     

Multi-channel gain and noise figure evaluation of Raman/EDFA hybrid amplifiers

We present detailed multi-channel experimental characterization of different configurations of single pump hybrid Raman-erbium doped fiber (EDF) amplifiers. The incorporation of an EDF section in a dispersion compensating Raman amplifier is demonstrated to provide superior performance than Raman only system. It is shown that the multi-channel gain spectrum is quite different form the single-channel case. We have also measured the polarization dependent gain (PDG) of the hybrid amplifier configurations and results show that different configurations of hybrid amplifiers have different PDG effects on long-haul optically amplified link.     

Requirements for Efficient Raman Amplification and Dispersion Compensation Using Microstructured Optical Fibers

The design and performance of microstructured optical fibers (MOFs) for simultaneous dispersion compensation and Raman amplification is numerically investigated. We studied a lumped Raman amplifier designed to compensate the signal loss and dispersion introduced by a 100-km, 16-channel C-band WDM link. The impairments induced by the nonlinearities caused by the small mode area of the designed MOF are investigated and the analysis is extended to include non-ideal factors such as excess background losses, splice loss, and the geometry variations during the fabrication process. The results are discussed and compared to those obtained for conventional dispersion compensating fibers (DCFs).     

Requirements for Efficient Raman Amplification and Dispersion Compensation Using Microstructured Optical Fibers

Abstract

The design and performance of microstructured optical fibers (MOFs) for simultaneous dispersion compensation and Raman amplification is numerically investigated. We studied a lumped Raman amplifier designed to compensate the signal loss and dispersion introduced by a 100-km, 16-channel C-band WDM link. The impairments induced by the nonlinearities caused by the small mode area of the designed MOF are investigated and the analysis is extended to include non-ideal factors such as excess background losses, splice loss, and the geometry variations during the fabrication process. The results are discussed and compared to those obtained for conventional dispersion compensating fibers (DCFs).     

Optimization of a Raman/EDFA hybrid amplifier based on dual-order stimulated Raman scattering using a single-pump

Based on dual-order stimulated Raman scattering (SRS) of a single 1395 nm Raman fiber laser in 75 km single mode fiber and its corresponding dispersion compensation module, a hybrid Raman/Erbium doped fiber amplifier (EDFA) for long wavelength band (L-band) amplification is realized by inserting a segment of EDF within the span. By comparing the performance of gain and noise in four hybrid amplifiers with different span configurations, we find that the distribution of the secondary L-band amplification obtained from the EDF along the link has a great influence on the performance of the hybrid amplifier. Both gain and noise performance of hybrid amplifier can be improved significantly by optimizing the location of the EDF. Moreover, we can extend the flat gain bandwidth from L-band to central wavelength band (C-band) plus L-band by recycling the residual first-order SRS to pump a segment of EDF with proper length.     

Single-wavelength-pump bi-directional hybrid fiber amplifier for bi-directional local area network application

This paper proposes a novel bi-directional hybrid fiber amplifier using a single-wavelength pump laser diode (LD) at 1495 nm. The hybrid amplifier is theoretically applied in a 50 km bi-directional local area network (LAN) with 26 ch × 10 Gb/s for bi-directional transmission. Thirteen C-band channels serve as downlink signals while the other 13 L-band channels are employed as uplink signals. Without loss of generality, four channels (two from each band) are experimentally analyzed. Erbium doped fiber (EDF) provides amplification for the C-band channels and Raman amplification amplifies the L-band channels. The pump efficiency is improved by employing a double-pass scheme for both the Erbium doped fiber amplifier (EDFA) and Raman fiber amplifier (RFA). The chromatic dispersion incurred by all the channels is precisely compensated for by inserting a fiber Bragg grating (FBG) array in appropriate locations along the dispersion compensating fiber (DCF) segments. Moreover, gain equalization of all the channels is achieved by adjusting the FBG reflectivity. Both the simulation results and experimental measurements confirm the proposed device feasibility and potential application in a bi-directional LAN.     

Optimization of NRZ Data Transmission at 10 Gbit/s over G.652 Without In-Line DFAs

Performance limits of NRZ data transmission at 10 Gbit/s over standard single mode fiber (SSMF, G.652) without the deployment of in-line erbium-doped fiber amplifiers (EDFAs) are evaluated by means of numerical simulation. The fiber system was modeled using the standard split-step Fourier algorithm for the solution of nonlinear Schroedinger equation. The effect of group velocity dispersion (GVD) compensation scheme, degree of GVD compensation of the SSMF, and input optical powers to SSMF and to the dispersion compensating fiber (DCF) have been investigated with the aim to maximize the distance between transmitter and receiver. We have found that a post-compensation scheme performs better than the pre-compensation scheme and that, by careful selection of input powers and degree of GVD compensation, it should be possible to keep the bit-error-ratio (BER) below 10 upper index = 15 for an SSMF length of 270 km.     

Optimization of NRZ Data Transmission at 10 Gbit/s over G.652 Without In-Line DFAs

Performance limits of NRZ data transmission at 10 Gbit/s over standard single mode fiber (SSMF, G.652) without the deployment of in-line erbium-doped fiber amplifiers (EDFAs) are evaluated by means of numerical simulation. The fiber system was modeled using the standard split-step Fourier algorithm for the solution of nonlinear Schroedinger equation. The effect of group velocity dispersion (GVD) compensation scheme, degree of GVD compensation of the SSMF, and input optical powers to SSMF and to the dispersion compensating fiber (DCF) have been investigated with the aim to maximize the distance between transmitter and receiver. We have found that a post-compensation scheme performs better than the pre-compensation scheme and that, by careful selection of input powers and degree of GVD compensation, it should be possible to keep the bit-error-ratio (BER) below 10 upper index = 15 for an SSMF length of 270 km.     

The Raman non-gain and self-steepening effects in Raman fiber amplifiers

In Raman fiber amplifiers, due to the strong pump power, the self-steepening effect and Raman non-gain term should be taken into account even for the pico-second pulse's transmission. A model including these effects is established based on the resonant and no-resonant terms of cubic susceptibility tensor (x⁽³⁾). These extra effects will result in the requirement of strict dispersion compensation, which means the second-, third- and fourth-order dispersion should be compensated exactly. Till 95% of the fourth-order dispersion is compensated, 80 fs pulse can keep its shape successfully after 2000 m transmission in Raman amplifiers.     

Zero-Loss Broadband Dispersion Compensation Scheme for G.652 Fibers

We have evaluated the gain characteristics of an erbium-doped broadband dual-core dispersion compensating fiber (DCF) to achieve a loss-less dispersion compensating module for long-haul G.652 fiber links.     

17-channels S band multiwavelength Brillouin/Erbium Fiber Laser co-pump with Raman source

In this paper, we propose and demonstrate a stable Brillouin-Erbium Fibre Laser (BEFL) capable of generating up to 17 lasing wavelengths in the Short-Wave length (S-band) region. The proposed setup uses a 7.7 km Dispersion Compensating Fibre (DCF) to act as a non-linear gain medium and a 30 m long Depressed-Cladding Erbium Doped Fibre (DC-EDF) as an optical amplifier for amplification in the S-band region. The proposed BEFL has an optimum tuning range of 1499 to 1502 nm and is capable of generating 17 lasing wavelengths with peak powers of between −20 to −15 dBm when injected with a Brillouin Pump (BP) of 5 dBm at 1499 nm and a Raman Pump (RP) of 300 mW at 1420 nm.     

光孤子脉冲在光纤放大器中的传播

本文建立了包括增益色散,受激喇曼散射,双光子吸收效应的理论模型,讨论了光孤子脉冲在光纤放大器中的传播.数值计算结果表明:在反常色散范围内,光孤子的放大是不稳定的.增益色散导致光脉冲对称分裂,而受激喇曼散射则导致不对称的分裂.在增益色散和受激喇曼散射的共同作用下可获得新的时域和频域特征.有限带宽的放大能抑制受激喇曼散射引起的自频移.本文对有啁啾的光孤子脉冲的放大也进行了分析.     

Amplification of picosecond pulses and gigahertz signals in bismuth-doped fiber amplifiers

We demonstrate the capability for amplification of picosecond pulses in two bismuth-doped alumosilicate fibers. A spectrally filtered supercontinuum source is used to provide a train of picosecond pulses at discrete wavelengths within the gain bandwidth of bismuth fiber amplifiers. With a 30 m length of active fiber, a small signal gain at 1160 nm of over 20 dB is observed. In addition, we assess the viability of amplification of high repetition rate signals in such amplifiers, applying a 10 GHz modulation to a continuous wave Raman fiber laser operating at 1178 nm, finding that such signals are amplified without noticeable distortion.