宽可调谐自起振被动锁模掺铒光纤激光器

分析了利用非线性偏振旋转效应作为等效可饱和吸收体锁模的原理,并用该方法构建起环形腔被动锁模掺铒光纤激光器,结合可调谐滤波器腔外滤波的方法实现锁模脉冲波长的连续可调谐.实验中得到自起振、平均输出功率0.313 mW,脉冲半极大全宽度(FWHM)1.5 ps,中心波长1562.3nm,重复频率13.9MHz的稳定被动锁模脉冲序列输出,滤波后输出脉冲中心波长在1553.2～1571.4 nm内连续可调,得到谱宽2.5 nm以下,脉宽小于1.8 ps的限变脉冲输出.     

利用普通色散位移光纤得到的超宽带超连续谱

对实验中观察到的超连续谱（SC）演变过程进行了理论分析.在泵浦光平均功率55 mW时,利用普通色散位移光纤得到SC谱从1311 nm到1780 nm的展宽.其中泵浦波长右侧196 nm范围内的光谱不平坦度＜±1 dB.利用F-P进行谱切片,在泵浦波长右侧和左侧分别得到92个和46个顶部平坦的信道.将色散位移光纤长度缩短到100 m时,还得到了SC谱20 dB带宽453.3 nm的实验结果,实现了无缝覆盖S带、C带、和L带.     

Ultra-broadband supercontinuum generated in dispersion-flattened fiber

With 4.28-km dispersion-flattened fiber (DFF), more than 254.9-nm 10-dB bandwidth on the right side of zero-dispersion wavelength and a 190.4-nm wide spectral region with the uniformity of within ±0.5 dB are obtained. While on the opposite side, 198.4-nm 10-dB bandwidth and 62.3-nm spectral region with the uniformity of within ±0.5 dB are obtained. More than 88 channels spaced at 2.52 nm on the long wavelength side are generated using Fabry-Perot (F-P) filter. The output supercontinuum (SC) characteristic is also analyzed by spectrum carving.     

Ultra-broadband supercontinuum generated in dispersion-flattened fiber

With 4.28-km dispersion-flattened fiber (DFF), more than 254.9-nm 10-dB bandwidth on the right side of zero-dispersion wavelength and a 190.4-nm wide spectral region with the uniformity of within ±0.5dB are obtained. While on the opposite side, 198.4-nm 10-dB bandwidth and 62.3-nm spectral region with the uniformity of within ±0.5 dB are obtained. More than 88 channels spaced at 2.52 nm on the long wavelength side are generated using Fabry-Perot (F-P) filter. The output supercontinuum (SC)characteristic is also analyzed by spectrum carving.     

色散平坦光纤中的超连续谱

利用光纤中的超连续(SC)谱展宽技术,能够在很宽的光谱范围内同时获得多个高重复率、多波长超短脉冲,是一种有效的超短脉冲光源产生方法.本文利用重复频率为13.9MHz,脉宽1.5ps的超短脉冲泵浦色散平坦光纤(DFF),在三阶非线性效应(自相位调制、交叉相位调制、受激喇曼散射)和色散联合作用下得到总宽度510nm以上的SC光谱,并在宽150nm的谱段内获得不平坦度小于±0.25dB,且覆盖全部L波段的SC谱;用可调谐滤波器在此区段谱切片滤波,并得到脉宽基本相同的接近变换限的超短脉冲.     

金色链霉菌原生质体的制备

对金色链霉菌原生质体制备的具体条件进行了优化研究 .发酵培养基中采用蔗糖浓度 12 %、甘氨酸浓度 0 .5 %、酶解条件采用菌龄为 48h的菌丝、溶菌酶浓度 6mg/mL、酶解时间为 1h制备原生质体 ,原生质体制备率可高达 6 0 %以上 .