半导体激光器实现波长转换的理论模型分析

作为自动交换光网络中的核心器件，全光波长转换器的研究是目前的热点。提出了基于半导体激光器实现波长转换的理论模型，采用小信号分析方法，利用速率方程求解了波长转换的频率调制响应特性。并初步研究了不同半导体激光器工作电流、码速、输入信号光功率、增益吸收系数条件对波长转换性能的影响。这对于优化基于半导体激光器的全光波长转换器有一定的参考价值。     

基于半导体激光器的全光波长转换的理论研究

全光波长转换是全光网络的关键技术之一。利用多模半导体激光器的速率方程,建立了基于半导体激光器的全光波长转换器的理论模型,该模型不仅考虑了注入信号光对激光腔内载流子的消耗,而且考虑了激光腔对注入信号光的放大作用。利用该模型分析了半导体激光器工作电流、注入信号光功率以及码率各参数对波长转换特性的影响。结果对于确定基于半导体激光器的全光波长转换器件的最佳工作条件有一定的参考价值。     

基于单端耦合SOA的波长转换器啁啾特性分析

提出了一种基于单端半导体光放大器（SOA）的交叉增益调制型（XGM）全光波长转换器结构, 并针对这种结构建立了动态理论模型, 以这个模型为基础分析了泵浦光功率、探测光功率、输出消光比、输入消光比对转换后信号啁啾的影响. 结果表明利用这种结构的波长转换器实现波长转换, 在提高输出消光比的同时也降低了转换光的啁啾, 较传统的波长转换器是一种改进.     

新型结构可调谐全光波长转换器的理论与实验研究

可调谐波长转换器是智能化光网络中的关键光电子器件. 提出了一种基于半导体光放大器的环形激光器实现连续可调全光波长转换的方案，建立了该方案的理论模型. 理论计算和实际测定了不同条件下波长转换的输出特性，实验结果与理论计算基本符合. 实验中实现了40nm范围内连续可调、转换速率为2.5Gb/s的交叉增益调制型波长转换. 关键词： 可调谐波长转换 半导体光放大器 环形腔     

基于半导体光放大器交叉偏振调制的波长转换理论研究

在半导体光放大器中,采用由张应变引起的自身双折射理论模型对交叉偏振调制型全光波长转换器的波长转换特性进行了数值研究,并对数值结果与相关实验进行了对比。结果表明:通过调节系统参量,可以实现同相或反相波长转换;同相和反相波长转换时输出的信号啁啾、消光比和眼图具有不同特性;随着数据传输速率的增加,输出信号的眼图张开度减小,啁啾变大。     

基于光纤光栅外腔激光器的全光波长转换器的阈值转换特性

使用半导体激活介质的增益饱和效应,描述了激光器型全光波长转换器波长转换机制及其阈值转换特性.实验研究了基于光纤光栅外腔半导体激光器的全光波长转换器的阈值转换特性,结果表明以此器件作为波长转换器可以将信号的消光比由5dB提高到30dB,并可将信号的强度起伏抑制到0dB,可实现部分信号数字再生功能.     

基于光纤中受激喇曼散射效应的全光多波长转换耦合器EI北大核心CSCD

基于光纤中受激喇曼散射效应,运用级联同种光纤设计出全光多波长转换耦合器,使转换输出的各路信号光功率相等.建立了全光多波长转换设计方案的理论模型,给出了设计原理框图以及实现方法,并以1路泵浦信号光、4路连续探测光为例,通过OptiSystem软件进行了仿真,仿真结果表明:所设计的全光多波长转换耦合器能同时对4路探测光实现波长转换,转换输出的信号光码型和输入泵浦信号光码型基本一致;转换效率和消光比随着探测光波长的增大而增大,最大值分别为-34dB和36.68dB;Q因子随着探测光波长的增大而减少,最大值为128.29;在级联光纤之后,4路输出信号光峰值功率和消光比基本相等,Q因子整体数值相对于全光多波长转换后有所下降,最大值为89.5455,验证了该方案的可行性.     

基于光纤环形腔激光器的可调谐全光波长转换器的研究

在光纤环形腔激光器中引入周期极化反转铌酸锂(PPLN)光波导，用该激光器产生的连续光作为抽运光和控制光，使其与外加的信号光发生非线性效应实现可调谐波长转换.介绍了基于准相位匹配的PPLN光波导中的和频与差频级联型全光波长转换器的基本原理.对抽运光、信号光、控制光以及转换光的光功率随着PPLN光波导的变化进行了模拟.还对转换效率随着转换光波长的变化进行了数值计算.实验验证了该波长转换器的可调谐性. 关键词： 周期极化反转铌酸锂 和频与差频 可调谐全光波长转换 光纤环形腔激光器     

准相位匹配级联二阶非线性全光波长转换研究

对基于级联和频差频非线性效应铌酸锂光波导新型全光波长转换器进行了理论研究。这种新型波长变换器需要两束抽运光源,它将输入的抽运光波长置于信号光波段窗口的两边,抽运光波长与信号光波长相近容易实现最佳耦合又不会占用信号波段,而且具有偏振不敏感的优点。从建立级联和频差频铌酸锂光波导全光波长转换器的理论模型出发,给出了波导中光相互作用的耦合模方程;利用逐步法详细推导了耦合模方程的解,得出了物理意义清晰的转换光功率表达式,分析了非线性晶体相互作用长度、抽运光功率对转换效率的影响,为级联和频差频铌酸锂光波导全光波长转换器优化设计提供了理论依据。     

基于SFRL的FWM型可调谐波长转换器啁啾特性分析

基于半导体光纤环形腔激光器的四波混频型可调谐全光波长转换器的宽带理论模型,从理论上研究了输入信号光功率、注入电流、两个耦合器的耦合比、激射光波长和半导体光放大器有源区长度对转换光频率啁啾的影响.结果表明:转换光的频率啁啾随着输入信号光峰值功率、注入电流以及SOA有源区长度的增大而增大,随两个耦合器耦合比的增大而减小.     

基于少模光纤被动调Q柱矢量光光纤激光器

通过单模光纤和少模光纤熔融拉锥耦合的方法制备出模式转换器,而后将一层多壁的碳纳米管薄膜作为可饱和吸收体覆盖到拉锥光纤的锥区,形成一种可饱和吸收体柱矢量光器件.结合调Q光纤激光器和模式转换器件的优势,可以简单高效地产生脉冲柱矢量光束,并得到具有峰值功率高、模式纯度高等特点的脉冲高阶模式激光输出.通过实验实现了中心波长为1560nm、最大单脉冲能量和最大峰值功率分别为116nJ和57mW的稳定调Q脉冲输出.通过调节光路中的偏振控制器,可以分别实现径向和角向偏振的调Q脉冲激光的输出.     

Wavelength conversion of 1.53-microm-wavelength picosecond pulses in an ion-implanted multiple-quantum-well all-optical switch

An ultrafast high-contrast all-optical switch produced from a metal-organic vapor phase epitaxy-grown wafer incorporating a 50-period InGaAsP/InGaAsP multiple-quantum-well (MQW) saturable absorber (SA) and a distributed Bragg reflector is described. Postgrowth implantation with 4-MeV nitrogen ions reduces the MQW free-carrier lifetime, and hence the switch recovery time, to 5.2 ps. Incorporation of the MQW SA in an optical cavity results in switching contrast ratios greater than 10 dB. The all-optical switch is used to perform wavelength conversion of 2-ps pulses.     

Diode-pumped passively mode-locked Nd:Lu0.15Y0.85VO4 laser with a single-walled carbon nanotube saturable absorber

Diode-pumped passively mode-locked Nd:Lu_0.15Y_0.85VO₄ laser with a single-walled carbon nanotube saturable absorber was demonstrated for the first time, to our best knowledge. The laser generated 19-ps pulses with maximum output power of 902 mW for the incident pump power of 6.5 W at the central wavelength of 1064 nm, giving an optical conversion efficiency of 14%. The continuous wave mode-locking conditions of single-walled carbon nanotube saturable absorber were analyzed and discussed.     

Multi-wavelength Q-switched erbium doped fiber laser with a short carbon nanotube based saturable absorber

We demonstrate an all-fiber passively multi-wavelength Q-switched Erbium doped fiber laser (EDFL) based on a short Carbon Nanotube based saturable absorber. With the saturable absorber connected in a longer standing wave based fiber laser cavity, stable single, dual, and multiple wavelength Q-switched low threshold EDFL are achieved. Experimental results show that the output pulse of the filtered single wavelength has the same repetition rate as that of the multi-wavelength output while its average output power is lower than that of the multi-wavelength output.     

Obtaining Single Picosecond Pulses in a Short-Cavity Dye Laser with Switching of Lasing to the Saturable Absorber

A new method of lasing of single picosecond pulses in a short-cavity dye laser with spatial separation of the lasing medium and the saturable absorber in the case of pumping by nanosecond pulses with energies much higher than the oscillation threshold has been developed and experimentally realized. The method is based on the use of a high-Q, external cavity tuned to the amplification wavelength of the saturable absorber. The first picosecond pulse is lased at a lasing-medium wavelength and the subsequent pulses are lased at a saturable-absorber amplification wavelength.     

Passively Q-switched cylindrical vector laser based on a black phosphorus saturable absorber

We demonstrate an all-fiber Q-switched cylindrical vector laser based on a black phosphorus saturable absorber and a transverse mode converter. The saturable absorber is prepared by incorporating the polyvinyl alcohol with anti-oxidized black phosphorus nanosheets exfoliated in aqueous poly(dimethyldiallyl ammonium chloride)solution. The mode converter is composed of a tapered two-mode fiber and a single-mode fiber, and it can excite switchable azimuthally and radially polarized beams by modulating the input polarization. By enhancing the pump power from 64.68 to 174.82 mW, the repetition rate of the Q-switched azimuthally/radially polarized laser enlarges from 16.72/19.25 to 30.71/37.82 kHz.     

All-optical wavelength converter based on fiber cross-phase modulation and fiber Bragg grating

I present new method of phase modulation to amplitude modulation conversion (PM/AM conversion) that utilizes integrating capabilities of fiber Bragg grating (FBG). I found that the wavelength converter based on fiber cross-phase modulation (XPM) and new method of PM/AM conversion have an order of magnitude higher conversion efficiency then the wavelength converter based on sideband filtration method and up to 6 dB higher conversion efficiency then the converter based on the nonlinear optical loop mirror. Numerical analysis and experimental results are provided for bit rates up to 40 Gb/s.     

1.5-microm monolithic GaInNAs semiconductor saturable-absorber mode locking of an erbium fiber laser

We present a new monolithic GaAs-based semiconductor saturable absorber operating at 1.55 microm. An epitaxially grown absorber mirror in a GaInNAs/GaAs material system was successfully used to mode lock an erbium-doped fiber laser. The GaInNAs material system possesses intriguing physical properties and provides great potential for lasers and nonlinear optical devices operating at the 1.3-1.55-microm wavelength range.