掺杂光纤激光特性分析

本文用速率方程方法和半经典理论方法分析了光纤激光器与光纤放大器的工作原理及工作特性.导出了光纤最佳长度与泵浦功率、掺杂浓度的关系;以及增益与光纤长度,泵浦功率的关系.指出了泵浦光的最佳频率选择,同时,也分析了激光器工作波长与光纤长度的关系。     

一种高稳定DBR 型掺铒光纤激光器研究

研制了一种高功率高边模抑制比及高波长稳定性的DBR 型掺铒光纤激光器。该激光 器使用980nm LD 作为泵浦源,并使用长度为2. 75m 的高掺杂浓度的掺饵光纤作为增益介质,在1. 55μm 波段获得了3dB 线宽为0. 2nm ,25dB 线宽为0. 4nm 的激光输出。最大输出光功率25mW ,输出功率稳定性±0. 01dB ,边模抑制比60dB ,波长稳定性0. 01dB (受光功率计精度的限制) ,阈值泵浦光功率8. 6mW ,斜率效率21. 7 %。     

一种高稳定DBR 型掺铒光纤激光器研究

研制了一种高功率高边模抑制比及高波长稳定性的DBR型掺铒光纤激光器。该激光器使用980nmLD作为泵浦源,并使用长度为2.75m的高掺杂浓度的掺饵光纤作为增益介质,在1.55μm波段获得了3dB线宽为0.2nm,25dB线宽为0.4nm的激光输出。最大输出光功率25mW,输出功率稳定性±0.01dB,边模抑制比60dB,波长稳定性0.01dB(受光功率计精度的限制),阈值泵浦光功率8.6mW,斜率效率21.7%。     

掺镱双包层高功率光纤激光器输出特性研究

对线形腔掺镱双包层高功率光纤激光器的输出特性进行了研究 ,通过求解速率方程 ,得到了激光器泵浦阈值功率、输出光功率和斜率效率的表达式。分析了光纤长度、腔镜反射率和泵浦波长等因素对激光器阈值功率、输出光功率和斜率效率的影响 ,为高功率光纤激光器的优化设计提供了理论依据     

高掺铒光纤光谱及增益特性研究

对高掺铒浓度光纤的增益及光谱特性进行了实验研究.仅用增益长度2.75米的高掺铒光纤,对于1530nm～1560nm波段0dBm的输入信号,其放大后的输出功率可达+14dBm,且其噪声指数低于4.5dB.所用980nm泵浦源的泵浦功率为80mW.得出掺铒光纤的平坦增益谱宽为30nm(±1dB),其输出功率与输入信号功率呈线性关系.实验测得其1550nm光信号增益为43dB.     

光子晶体光纤中四波混频光谱增益特性的研究

采用脉冲宽度为5 ps、峰值功率为5 W的可调谐钛宝石激光器泵浦长度为4.8 m,零色散点在810 nm的光子晶体光纤(PCF),观察到四波混频(FWM)3 dB的信号光增益,信号光和闲频光的间距为20 nm.通过调谐泵浦光的入射中心波长,研究了不同泵浦波长对FWM信号增益的影响,并与理论结果进行了对比,结果表明了很好的一致性.     

基于Sagnac环镜的多波长线性腔掺铥光纤激光器(特邀)

研究了一种基于光纤Sagnac环镜的多波长线性腔掺铥光纤激光器.该激光器采用1.5 m长的双包层掺铥光纤为增益介质,793 nm激光二极管为泵浦源,光纤Sagnac环镜和光纤环形镜构成激光器谐振腔.通过增加泵浦功率和调节偏振控制器,在1949～1976 nm的光谱范围内实现了1～7个波长的激光输出,输出功率达毫瓦量级,光信噪比达到40～50 dB.     

宽带拉曼光纤放大中的多泵浦源选择方法

理论分析了拉曼光纤放大谱与多波长泵浦光功率和波长的关系.考虑到泵浦光与泵浦光,泵浦光与信号光的拉曼相互作用,得出一个增益数组,增益数组就是离散的宽带拉曼光纤放大增益谱.对任何形态的宽带拉曼光纤放大增益谱,可以设定对应的增益数组,把泵浦光功率和波长组成二维坐标系,遍取坐标系中的各点,求出各组点对应的增益数组,找出最接近设定的增益数组,这组泵浦光功率及波长就是最优的解决方案.     

一种高性能环形可调谐光纤光栅激光器研究

研制了一种新型的高性能环形可调谐光纤光栅激光器。该激光器使用980nm LD作为泵浦源,使用长度为10. 8m的新型增益平坦掺铒光纤作为增益介质,采用可调谐光纤光栅滤波器进行波长调谐,调谐范围可达41nm (1528nm～1569nm) ,中心波长可精确调谐到C波段指定的ITU - T标准中心波长处, 3dB 带宽< 0. 08nm, 25dB带宽< 0. 2nm,波长稳定性优于0. 01nm,边模抑制比> 60dB。最大输出功率46. 94mW,功率稳定性优于±0. 02dB,阈值泵浦功率7. 3mW,斜率效率为39. 75%。并分析了不同腔长、不同输出耦合比对输出功率的影响。     

带反射镜双包层Er-Yb共掺光纤放大器性能研究

基于速率方程和传输方程,理论分析了带反射镜双包层ErYb共掺光纤放大器的输出信号功率和噪声性能。由于反射镜对剩余泵浦光的反射作用,致使激活光纤中参与能量转换的泵浦光增加,从而改善了双包层ErYb共掺光纤放大器的输出性能。数值结果表明,带反射镜光纤放大器只需要无反射镜光纤放大器激活光纤长度的一半,便能获得与之基本相等的高功率输出信号;对于同向泵浦和反向泵浦方式,其噪声系数均低于4dB。     

Parallel pump-shared linear cavity laser array using 980-nm pumpreflectors or N pieces of gain fibers as self-equalizers

By using fiber gratings as pump reflectors with various reflectivities or N pieces of gain fibers with various lengths externally to linear cavity as self-equalizers, a parallel-type, pump-shared linear cavity laser array (LCLA) is proposed and numerically studied. The average output power is increased and the maximum power variation among channels is reduced from 7.2 to less than 0.1 dB when the reflectivity of each pump reflector or the length of each gain fiber is adjusted appropriately     

High-repetition-rate pulsed-pump fiber OPA for amplification of communication signals

The use of a high-repetition-rate pulsed-pumped fiber optical parametric amplifier (OPA), followed by a narrow optical filter for transparent signal amplification, was proposed. Theory and simulations predict larger gain and gain bandwidth compared to a continuous-wave pump with the same average power. Experimentally, when using a pump with 0.63 W of average power in a 500-m-long highly nonlinear fiber, the gain increased from 19.7 to 29.2 dB, and the bandwidth increased when a CW pump was changed to one that is modulated by a 20-GHz cosine-squared function. Clear eye openings were demonstrated for the amplification of a 10-Gb/s NRZ signal, with a power penalty of 1.5 dB.     

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     

An erbium-doped multimode optical fiber amplifier

The authors describe the first experimental study of an erbium-doped multimode fiber amplifier. The focus has been to characterize an intermediate core erbium-doped optical fiber, a fiber that is capable of propagating many guided modes at both the signal and pump wavelengths, and to determine the feasibility of using such an active fiber as a multimode fiber amplifier, by measuring its gain, noise, and pump power requirements. For a 2-m length of a 13-μm-core erbium-doped fiber, the authors measured gain as high as 16 dB at a signal wavelength of 1543 nm, with approximately 100 mW pump power (980 nm). For these same test conditions, the smallest excess noise factor β was 42     

Characteristics of a semiconductor laser pumped brillouin amplifier with electronically controlled bandwidth

We demonstrate the operation of a semiconductor laser pumped fiber Brillouin amplifier. An optical gain of 5.5 dB/mW of pump power is obtained. The 15-MHz intrinsic bandwidth of the amplifier was extended more than one order of magnitude by adding frequency modulation to the pump laser. Bit-error-rate receiver sensitivity measurements with an in-line Brillouin amplifier demonstrate a 16-dB improvement in the system gain at 10 Mbit/s and a 8.5-dB improvement at 90 Mbit/s. Noise calculations show that the amplifier has an excess noise factor of 50-500 depending on the amplifier length and pump power.     

L-波段级联结构掺Er光纤放大器的优化设计

在前级Er光纤（EDF）长度和抽运功率确定的前提下，通过改变后级抽运功率，对L波段级联结构掺Er光纤放大器（EDFA）的两级光纤长度的比例进行了优化研究。当前级的抽运功率和光纤长度分别为60mW和5．4m时，通过对后级参数进行优化，小信号增益达到了30．1634dB，同时噪声指数仅为4．078dB。与其它设计方案相比，该方案更具有实用性：首先，可以通过选择适当的后级抽运功率使级联放大器得到足够大的增益；其次，可以充分利用抽运光能量，从而提高抽运利用效率。     

Acceleration of gain recovery in semiconductor optical amplifiersby optical injection near transparency wavelength

By using optical injection near the transparency wavelength of semiconductor optical amplifiers, we show experimentally that both the saturation output power and the gain recovery can be greatly improved. By injecting 80 mW of pump power, we observe a 3-dB increase in saturation output power. For 73 mW of pump power, we find a reduction in gain recovery time from over 200 ps down to below 40 ps, while maintaining 14 dB of fiber-to-fiber gain at 1555-nm wavelength     

Long-wavelength monolithic GaInNAs vertical-cavity optical amplifiers

We report on the continuous-wave amplification characteristics of an optically pumped 1.3-/spl mu/m multiple-quantum-well GaInNAs-GaAs vertical-cavity semiconductor optical amplifier (VCSOA). The VCSOA structure was monolithically grown by molecular beam epitaxy and operated in reflection mode in a fiber-coupled system. The maximum on-chip gain attained, limited by the onset of laser action, was 15.6 dB at 196 mW of 980-nm pump power. For a chip gain of 10.4 dB, the optical bandwidth was 10.8 GHz and the saturation output power was -9 dBm. By varying the pump laser power, a maximum extinction ratio of 22.3 dB was obtained. Temperature-controlled tuneable operation of the device is also presented and demonstration of 9 dB of chip gain obtained over 9.5 nm with an optical bandwidth of 12 GHz is reported.     

Characteristics of regenerative erbium-doped fibre ring amplifier

A study is presented into the dynamic characteristics of a unidirectional regenerative erbium-doped fibre ring amplifier at below laser threshold. A considerable improvement in gain and noise figure performance was observed due to the suppression of amplified spontaneous emission in the regenerative amplification process. It was found that lower feedback power provides higher optical gain. An optical signal of -33.5 dB was found to experience a gain of ⩾35 dB at and near the resonance wavelength using 1% feedback by an optical fibre coupler for an optical pump (1480 nm) power as low as 10 mW     

Er3+-doped fiber amplifier pumped by 0.98 μm laserdiodes

The performance of an Er³⁺-doped fiber amplifier pumped by 0.98 μm InGaAs laser diodes (LDs) is reported. By using a fiber with low Er³⁺ content and optimizing the fiber length, a maximum signal gain of 37.8 dB at 30-mW pump power was realized at a signal wavelength of 1.536 μm. A maximum gain coefficient of 1.9 dB/mW at 14 mW pump power was achieved. It was found that the fiber amplifier pumped by the 0.98-μm LDs is twice as efficient as that pumped by 1.48-μm LDs, from the viewpoint of both required fiber length and the attained gain