宽带碲基掺铒光纤放大器上能级粒子数反转比

对宽带碲基掺铒光纤放大器(EDTFA)上能级粒子数反转比进行了理论研究,得到了碲基掺铒光纤放大器上能级粒子数反转比随着光纤激活长度、信号输入功率、泵浦功率和纤芯掺杂浓度的演变关系,分析了上能级粒子数反转比分布与EDTFA信号增益间的关系.研究表明,碲基掺铒光纤内的上能级粒子数反转比分布决定了EDTFA的信号增益.     

宽带碲基掺铒光纤放大器掺杂特性的理论研究

对WDM系统中宽带碲基掺铒光纤放大器(EDTFA)多信道增益谱特性的研究表明,在给定泵浦方式、泵浦功率和光纤长度的工作条件下,碲基掺铒光纤中铒掺杂浓度对EDTFA各信道信号增益的影响并不相同,相比于长波长信道,短波长信道的信号增益随着光纤中铒掺杂浓度的提高更易趋于饱和及快速衰减状态,同时信号增益谱向长波长方向萎缩.     

碲基掺铒光纤放大器增益特性的理论研究

在综合考虑Er^3 离子的能量上转换、交叉驰豫、激发态吸收效应以及光纤背景损耗后，依据所建立的均匀加宽四级结构速率方程组和光功率传输方程组，对碲基掺铒光纤放大器的增益特性进行了数值模拟，模拟结果与报道的实验测量结果达到了很好的一致。同时，对碲基掺铒光纤放大器的增益特性与输入信号功率、泵浦功率和光纤长度的关系进行了简要分析。     

带光隔离器的双包层EYDFA特性研究

基于速率方程和光传输方程,对带光隔离器的级联双包层铒镱共掺光纤放大器(EYDFA)进行了研究.结果发现小信号条件下与单级结构相比,在三种泵浦方式中,前向泵浦级联结构的增益增加最多达到4.4dB,后向泵浦的增益最大,前向和双向泵浦的噪声系数接近理论极限3dB,前向泵浦的最佳光纤长度增大近1倍.     

980 nm和1480 nm LD混合泵浦两段级联掺铒光纤放大器实验研究

采用两段级联掺铒光纤、９８０ｎｍ和１４８０ｎｍＬＤ混合泵浦方式，实验分析比较了内插光隔离器和内插光隔离－耦合环光路结构掺铒光纤放大器（ＥＤＦＡ）的增益、噪声系数和输出功率特性。研制出内插光隔离－耦合环的ＥＤＦＡ，在信号波长１５５３．５ｎｍ处，小信号增益为４２．８ｄＢ，噪声系数为４．４ｄＢ，输出功率为１５．２ｄＢｍ。     

掺铒光纤放大器双向放大特性

建立了掺铒光纤放大器（ＥＤＦＡ）双向放大传输的方程，通过数值模拟计算，分析了掺铒光纤长度、泵浦功率的变化对增益、噪声系数的影响；研究了ＥＤＦＡ的正反向增益和噪声系数特性；给出了增益、正反向系数与输入信号功率的关系曲面。     

碲酸盐掺铒玻璃光纤放大器的瞬态响应

建立了一个数值模拟碲酸盐掺铒玻璃光纤放大器(EDTFA)瞬态响应的理论模型,理论上研究分析了低频方波脉冲输入信号经过EDTFA后的瞬态输出响应.研究结果显示,对于输入信号功率的跃变, EDTFA存在着一个快速的瞬态响应过程,响应时间小于报道的硅基掺铒光纤放大器(EDFA),说明EDTFA适合于泵浦调制及全光纤开关方面的应用场合.通过对双通道信号传输情形下关闭一个信道后另一信道输出功率瞬态响应的研究,揭示了适时调节泵浦功率快速稳定剩余信道输出功率的可行性.     

硫系玻璃基掺铒微结构光纤4.5μm波段中红外信号放大特性

为进一步揭示硫系玻璃基掺Er3+微结构光纤作为中红外光纤放大器增益介质的可行性,数值求解了800 nm泵浦波长下Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤中Er3+离子数速率方程和光功率传输方程组,理论研究了4.5μm波段中红外信号的放大特性。结果显示,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤具有较高的信号增益和很宽的增益谱。在50 cm光纤长度上,最大信号增益超过了40 dB,高于30 dB信号增益的放大带宽达到了280 nm(4 420~4 700 nm)。同时,进一步研究分析了4 500 nm波长信号增益与光纤长度、信号输入功率和泵浦功率的关系。研究表明,Ga5Ge20Sb10S65硫系玻璃基掺Er3+微结构光纤是一种理想的可应用于4.5μm波段中红外宽带放大器的增益介质。     

铒铥共掺碲基质宽带光纤放大器研究

文章作者分析了铒铥共掺碲基质光纤放大器在980 nm泵浦下Er~(3+)-Tm~(3+)离子之间的能量转移过程,建立了速率方程和功率传输方程,并通过仿真得出了其放大增益随光纤长度和泵浦功率的变化规律.仿真结果表明:通过优化光纤长度和泵浦功率,该放大器可以在1 440～1 540 nm波段得到高达50 dB的平坦增益.     

C+L波段宽带增益平坦铋基掺铒光纤放大器的设计

基于光纤放大器增益谱的宽带平坦化发展需要,设计了一个两段铋基掺铒光纤(Bi-EDF)级联并携带一个C波段(1 530~1 565 nm)宽带光纤布拉格光栅(FBG)的双通结构型铋基掺铒光纤放大器(Bi-EDFA),从理论上研究了其对输入信号的放大特性。研究表明:FBG的引入可以使C和L波段(1 570~1 620 nm)信号分别经历不同长度Bi-EDF的双向传输,各自获得高增益放大,实现增益谱的宽带平坦化。在200 mW的1 480 nm双向对称泵浦下,第一级和第二级Bi-EDF长度分别为50 cm和170 cm时,对于波长间隔为2 nm、每路功率为-30 dBm的56路C+L波段信号的输入,Bi-EDFA高于30 dB的增益带宽达到了90 nm(1 530~1 620 nm),平均增益为35.7 dB,增益起伏仅为2.3 dB。同时,噪声系数得到明显改善。研究结果对于研制具有宽带、增益平坦的C+L波段Bi-EDFA具有实际指导意义。     

Efficient erbium-doped fiber amplifiers incorporating an opticalisolator

A composite-EDFA configuration which incorporates an optical isolator has been investigated theoretically and experimentally. The isolator prevents the build-up of the backward-ASE and results in an amplifier with high gain and near-quantum-limited noise figure (NF). The optimum position of the isolator has been calculated as a function of the pump power so that minimum NF and maximum gain are achieved simultaneously. It is shown that under practical pump powers, the optimized composite EDFA exhibits a gain improvement of about 5 dB and a NF reduction in excess of 1.5 dB when compared with an optimized conventional EDFA. It is also shown that with further optimization the composite EDFA can be employed in a practical fiber link as a pre-amplifier without the use of an input isolator. Finally, a high-gain composite EDFA has been experimentally demonstrated which exhibits a gain of 51 dB (54 dB) and NF of 3.1 dB for only 435 mW (93 mW) of pump power     

碲基掺铒光纤放大器增益均衡的数值模拟

针对宽带碲基掺铒光纤放大器(EDTFA)本征增益谱不平坦特性,研究了采用双级串连结构,并在两段光纤中间加入增益均衡滤波器来实现增益平坦.模拟结果显示,通过设计一定结构的滤波谱,在37信道同时输入的情况下,铒离子掺杂浓度为4000 ppm时,使1536～1608 nm范围带宽内的增益达到了24 dB左右,噪声指数小于5.5 dB,增益谱的不平坦度小于1 dB;铒离子掺杂浓度为6000 ppm时,使1536～1608 nm范围带宽内的增益达到了23.5 dB左右.噪声指数小于5 dB,增益谱的不平坦度小于1dB.优化后的级连EDTFA可以满足WDM系统的要求.     

Quantum limited noise figure operation of high gain erbium dopedfiber amplifiers

Performance improvements obtained by using an isolator as an amplified-spontaneous-emission-suppressing component within erbium-doped fibers are evaluated. Simultaneous high-gain and near-quantum-limited noise figures can be obtained by such a scheme. The noise figure improves for input signal powers below -5 dBm, and an improvement of 2.0 dB with a simultaneous gain increase of 4.1 dB is measured relative to a gain-optimized fiber. The optimum isolator location is evaluated for different pump and signal wavelengths in both an Al/Er-doped and a Ge/Er-doped fiber, for pump and signal power variations and different pump configurations. In all cases the optimum isolator position lies within 10-37% of the total fiber length for small signal operation     

Erbium-doped fiber amplifier with 54 dB gain and 3.1 dB noisefigures

It is shown that for practical pump powers (<100 mW) a combination of high gain (>33 dB) and low noise figure (3 dB) cannot simultaneously be achieved with a conventional codirectionally pumped EDFA. However, using a codirectionally pumped composite EDFA incorporating an isolator overcomes the problem, and an amplifier with 51 dB (54 dB) gain and 3.1 dB noise figure (NF) for only 45 mW (93 mW) of pump power is demonstrated     

Optimum position of isolators within erbium-doped fibers

An isolator is used as an amplified spontaneous emission suppressing component within an erbium-doped fiber. The optimum isolator placement is both experimentally and theoretically determined and found to be slightly dependent upon pump power. Improvements of 4 dB in gain and 2 dB in noise figure are measured for the optimum isolator location at 25% of the fiber length when the fiber is pumped with 60 mW of pump power at 1.48 μm     

1.58-/spl mu/m broad-band erbium-doped tellurite fiber amplifier

This paper describes the development of a 1.58-/spl mu/m broad-band and gain-flattened erbium-doped tellurite fiber amplifier (EDTFA). First, we compare the spectroscopic properties of various glasses including the stimulated emission cross sections of the Er/sup 3+4/ I/sub 13/2/ /sup 4/I/sub 15/2/ transition and the signal excited-state absorption (ESA) cross sections of the Er/sup 3+4/ I/sub 13/2/ - /sup 4/I/sub 9/2/ transition. We detail the amplification characteristics of a 1.58-/spl mu/m-band EDTFA designed for wavelength-division-multiplexing applications by comparing it with a 1.58-/spl mu/m-band erbium-doped silica fiber amplifier. Furthermore, we describe the 1.58-/spl mu/m-band gain-flattened EDTFA we developed using a fiber-Bragg-grating-type gain equalizer. We achieved a gain of 25.3 dB and a noise figure of less than 6 dB with a slight gain excursion of 0.6 dB over a wide wavelength range of 1561-1611 nm. The total output power of the EDTFA module was 20.4 dBm and its power conversion efficiency reached 32.8%.     

Gain flattened Er3+-doped tellurite fibre amplifier forWDM signals in the 1581-1616 nm wavelength region

A gain-flattened Er³⁺-doped tellurite fibre amplifier (EDTFA) with an expanded L-band is presented. The amplifier has an average gain of 28 dB and a noise figure of <6 dB with a slight gain excursion of 1 dB over a wide wavelength range of 1581-1616 nm. The total output power of the EDTFA module was 20.5 dBm and its power conversion efficiency reached 25%     

Reflection insensitive erbium-doped fiber amplifier

It is experimentally and theoretically examined how the insertion of an isolator within the erbium-doped fiber influences the sensitivity of the fiber amplifier to external reflections. We examined the EDFA in various regions of saturation, and compared the configuration with the isolator to the traditional configuration without an isolator. The most significant improvements were found in the small-signal region, where the requirements to reflections may be relaxed by as much as 13 dB. This, together with an improved gain and noise figure, makes the configuration with the isolator very attractive for preamplifier applications     

A low-noise and gain-flattened amplifier composed of a silica-based and a fluoride-based Er/sup 3+/-doped fiber amplifier in a cascade configuration

We propose a novel low noise and gain-flattened Er/sup 3+/-doped fiber amplifier (EDFA) with a cascade configuration for wavelength division multiplexing (WDM) signals. In this configuration, a 1480-nm pumped fluoride-based EDFA is joined to a 980-nm pumped silica-based EDFA through an optical isolator. By adjusting the silica-based Er/sup 3+/-doped fiber length in the silica-based EDFA, we realized an excellent flat gain EDFA with a gain excursion of less than 0.9 dB and noise figure of 5.7/spl plusmn/0.2 dB, and a low noise EDFA with a noise figure of 5/spl plusmn/0.2 dB and a gain excursion of less than 1.4 dB, for 8 channel WDM signal in the 1532-1560-nm wavelength region.