高掺杂浓度掺镱光纤的光子暗化效应

采用光纤激光器和放大器结构方案，观察到了高浓度掺镱光纤（YDF）的光子暗化（Photo-darkening）现象.对激光器阈值和输出功率、放大器输出谱的测量结果表明，光子暗化效应导致了高掺杂浓度YDF的功率转换效率随泵浦作用时间的增加而下降，且下降为单调不可逆过程，但随着泵浦时间的增加，这种下降逐渐变缓、功率转换效率最终可趋于稳定.     

基于光纤激光器的中红外差频多波长激光产生

针对由YDFL和EDFL作为基频光源的QPM-DFG激光系统,利用PPMgLN晶体的色散关系及其温度特性,有效拓宽了QPM波长接受带宽.模拟结果表明,当采用1550和1060 nm波段的EDFL和YDFL分别作为DFG的信号和抽运光源时,对于相同的中红外波段,满足QPM条件所允许的抽运光波长变化范围远大于信号光波长变化范围.当固定信号光波长为1560 nm时,对于给定的晶体温度,1060 nm波段抽运光的QPM接受带宽超过17 nm,对应于中红外差频光带宽可约180 nm.采用多波长YDFL作为抽运源,单 关键词： 差频产生 准相位匹配 多波长中红外 光纤激光器     

Supercontinuum generated in all-normal dispersion photonic crystal fibers with picosecond pump pulses

The supercontinuum (SC) generation in all-normal dispersion (ANDi) photonic-crystal fiber (PCF) pumped by high power picosecond pulses are investigated in this paper. Our results show that an octave SC may be achieved by pumping the ANDi PCF with picosecond pump pulses. However, the PCF length required may have to be lengthened to several tens of centimeters, which is much longer than that with femtosecond pump pulses. The relatively long PCF gives rise to much higher Raman gain and stronger Raman frequency shift compared to those with femtosecond pump pulses, which in turn not only cause a distorted temporal waveform and an un-flattened spectrum, but also severely degrade the coherence of the generated SC.     

耦合广义非线性薛定谔方程的相互作用表象龙格库塔算法及其误差分析

本文通过表象变换, 将耦合广义非线性薛定谔方程 (C-GNLSE) 变换成相互作用表象中的向量方程, 再利用向量形式的4阶龙格-库塔迭代格式, 建立了一种在频域内求解C-GNLSE的同步更新迭代算法. 通过将该向量形式的相互作用表象中的4阶龙格-库塔 (V-JH-RK4IP) 算法应用于高双折射光子晶体光纤中超连续谱产生的数值模拟, 验证了算法的有效性, 通过与现有其他典型算法的比较, 表明以V-JH-RK4IP算法求解C-GNLSE具有最高的计算精度和计算效率. 关键词： 耦合广义非线性薛定谔方程(C-GNLSE) 相互作用表象 4阶龙格-库塔算法 超连续谱产生     

312 MHz,compact all-normal-dispersion Yb:fiber ring laser with an integrated WDM-ISO

A compact and stable all-normal-dispersion mode-locked ring fiber laser with the repetition rate of 312 MHz is obtained with a wavelength-division multiplexing isolator. The compressed pulse is nearly transform-limited and the pulse width is 118 fs. It exhibits an optical efficiency of 50% and the maximum output power is about 205 m W with a 410 m W pump.     

双向掺铒光纤放大器的特性分析

讨论了双向掺铒光纤放大器的结构方案,利用考虑放大的自发辐和北员耗影响的双向掺铒光纤放大器稳态放大速率方程模型分析的增益与掺铒光纤长度、输入信号光功率、帛运光功率及抽运方式等参数之间的关系,研究了单向和双向等功率抽运下正反向噪声系数随正反向信号光输入功率的变化行为。     

基于飞秒锁模光纤激光脉冲基频光的差频产生红外光梳

报道了一种基于飞秒锁模光纤激光脉冲基频光的光纤型差频产生(DFG)红外光梳及其研制技术.基于自主研制的重频锁定200 MHz飞秒锁模掺铒光纤激光器,经啁啾脉冲光纤放大与超连续谱产生技术,优化近零色散OFS光纤(型号:OFS-980-20)长度,结合可调延时线,获得了精准同步的基频双色脉冲;以GaSe为非线性晶体,利用光整流技术,产生了可在6—10μm范围内宽带调谐的DFG红外光梳,光梳最大光谱宽度可达1.3μm.这种光纤型远红外光梳可望在分子光谱精密测量等领域发挥重要作用.     

皮秒光纤激光脉冲两个关键问题的研究

窄带耗散孤子锁模光纤激光器可以产生接近变换限制的皮秒脉冲,但受非线性相移的限制,输出脉冲重复频率不能通过增加腔长来降低,脉冲能量仅在0.1 nJ以下,严重制约着这类皮秒脉冲的实际应用。提出一种通过耦合器抽取腔内脉冲能量、抑制腔内非线性相移积累,进而允许增加腔长来降低窄带耗散孤子皮秒光纤激光脉冲重复频率的方法。运用该方法,成功地将激光器重复频率由35.2 MHz降低到了1.77 MHz,且脉冲时频特性保持不变。提出了一种基于级间FBG陷波滤波的抑制皮秒脉冲光纤放大中光谱展宽的方法。通过简单地使用级间陷波滤波器,既可窄化第一级光纤放大器后的输出脉冲谱宽,允许采用第二级光纤放大器进一步提升脉冲能量,而且,还可将脉冲重塑为近高斯形,利用高斯脉冲光谱展宽斜率小的特点,允许第二级光纤放大器将脉冲能量提升得更高。利用该方法,在RMS（均方值）谱宽保持0.4 nm以内的前提下,10 ps脉冲经标准单模光纤放大器后,能量可由0.2 nJ可提升到10 nJ以上。     

Mid-IR Dual-Wavelength Difference Frequency Generation Using Fiber Lasers as Pump and Signal Light Sources

A continuous-wave mid-IR difference frequency laser source, which respectively uses an ytterbium-doped fiber laser as the pump source and a multiwavelength erbium-doped fiber laser cascaded with an erbium-doped fiber amplifier as the signal source, is demonstrated. Our experimental results show that two stable mid-IR radiation lines with a spacing of about 5.4nm may be simultaneously emitted by a suitable setting the pump and signal polarization orientations. The number of the mid-IR radiation lines is limited by the quasi-phase-matching acceptance bandwidth. By changing the PPMgLN temperature the two mid-IR radiation lines may be synchronously tuned in the mid-IR range between 3295 and 3356.3nm.