Band-selective C- or L-band erbium-doped fiber amplified spontaneous emission source

Two novel methods are demonstrated to build up a band-selective amplified spontaneous emission (ASE) broadband light source that can operate in the selective conventional band (C-band, 1525 similar to 1565 nm) or long-wavelength band (L-band, 1565 similar to 1605 nm) region using a 1 x 2 optical switch. With the backward ASE feedback technique, an output power of 27.6 mW for the C-band ASE and 11.8 mW for the L-band ASE are obtained while with the compound pump technique, a power of 24.5 mW for L-band ASE and 27.2 mW for C-band ASE are obtained both with a fixed total pump power of 100 mW. The advantage of using the backward ASE feedback technique is that the ASE source design is simpler whereas the power of L-band ASE is lower, and the notable advantage of using the compound pump technique is that the output powers of the two selective bands (C- or L-band) are balanced though the configuration is a little complicated. (c) 2006 Society of Photo-Optical Instrumentation Engineers

Research on Self-mixing Interference Effect and Micro-vibration Measurement of Semiconductor Laser at Moderate Feedback Condition

根据光反馈自混合干涉效应的基本理论模型,通过求解适度反馈下的相位方程,讨论了半导体激光器的运行模态及特性,并搭建自混合干涉测量实验系统进行实验研究,与模拟仿真结果进行对比分析。在此基础上,实验研究表明扬声器的振幅与驱动电压成良好的线性关系。The operating states and features of semiconductor lasers are discussed based on basic theory models of laser feedback self-mixing interference effect and phase equations at moderate feedback condition.Measurement experiment systems of self-mixing interference are built for experiment research,which are com pared and analyzed with the results of simulation.Based on this,the experiment research result shows that a good linear relationship between amplitude of loudspeaker and driving voltage is formed.国家自然科学基金(61108019); 福建省自然科学基金(2011J01368

拟穴青蟹抗菌肽Crustin新变体的表达特性与抗菌功能

Crustins是一类较早发现并广泛分布在甲壳动物中且富含半胱氨酸的阳离子抗菌肽,能够参与抗细菌的免疫应答。从拟穴青蟹（Scylla paramamosain）中克隆获得Crustin基因,命名为SpCrus1a,其cDNA序列全长744 bp,开放阅读框编码113个氨基酸,成熟肽分子量10.03 kDa,等电点8.30。表达分析结果发现其转录本主要存在于鳃、卵巢、上皮组织中,脂多糖刺激后SpCrus1a会上调表达。体外合成SpCrus1a的第29～47位氨基酸进行抗菌活性实验发现,其对革兰氏阳性菌具有较强的抗菌活性,对被测的革兰氏阴性菌抗菌活性较弱或无抗菌活性。合成肽Sp Crus1a29-47能够在较短时间内杀死绝大多数的金黄色葡萄球菌,2 h内杀死全部的金黄色葡萄球菌。扫描电镜发现合成肽Sp Crus1a29-47可造成金黄色葡萄球菌表面结构崎岖不平,高浓度Sp Crus1a29-47造成细菌的大量死亡。上述结果表明,SpCrus1a是抗菌肽Crustins的新变体。国家自然科学基金(U205123,31172438);;厦门南方海洋研究中心科技项目(14PYY050SF03

级联掺磷光纤喇曼激光器的解析优化

讨论了二级级联喇曼光纤激光器的解析解和优化设计.通过引入几何平均功率、增益因子和归一化光纤有效长度,将描述泵浦光和斯托克斯光沿喇曼增益光纤分布的微分方程组简化成代数方程组,在对泵浦光采用线性传播近似后,获得了二级级联喇曼激光器的解析解.所获得的解析解同数值模拟结果吻合得很好.利用该解析解可方便和快速地讨论级联喇曼激光器的优化设计,计算不同泵浦功率下的最佳光纤长度、输出光纤光栅反射率和转换效率.泵谱功率越大,最佳光纤长度越短,最佳输出光纤光栅反射率越小

Design and analysis on a Gires-Tournois resonator based interleaver

A flat-top interleaver,in which a mirror on one arm of the Michelson interferomefer is replaced by a G-T resonator,is proposed.In the interleaver,the parameters including the channel spacing of 50 GHz,ripple less than 0.05 dB,-0.5 dB passband of 43 GHz(86% of the spacing),-30 dB stopband of 42 GHz(84% of the spacing),and a channel isolation higher than 40 dB,are achieved

Characteristics of stable L-band SFS using dual-forward synchronous pumping technique

We investigate the characteristics of the dual-forward synchronously pumped L-band erbium-doped superfluorescent fiber source (SFS). The effects of pump ratio and fiber length arrangements on the output characteristics of the L-band SFS in terms of mean wavelength, spectral linewidth, and output power are analyzed. It is shown that the optimized pump ratio and fiber length arrangements provide broadening spectral linewidth and enhanced pumping efficiency, while the synchronous pump ensures stable mean wavelength operation. A new single-forward pumping scheme with a section of unpumped fiber is proposed to achieve a mean wavelength stable L-band SFS with a broadening linewidth of 50.4 nm and a pumping efficiency of 33.5%

基于复合型耦合器的新型透射式GT交错复用器及色散补偿

提出了基于复合型耦合器的透射式GT腔,并将其串入马赫-曾德尔干涉仪(MZI)的两臂上,得到了一种新型的交错复用器。推导了该器件的理论表达式,并进行了数值模拟。模拟结果表明,该交错复用器具有相当好的通带平坦性,大的通带带宽、截止度和阻带带宽。对该交错复用器进行了优化分析,发现腔数固定时,纹波带宽比越大(频谱越接近矩形方波),隔离度将越小。分析结果表明,可以通过增加腔的数量来解决纹波带宽与隔离度的矛盾,即交错复用器的频谱性能随着腔数的增加得以改善。相对于环形谐振腔辅助的交错复用器,该交错复用器不需要添加额外的相移器就能获得近似矩形的频谱,并且在整个工作波段范围具有很好的频谱均匀性。对于该器件的色散问题,提出了采用级联环形腔作为色散补偿器的补偿方案。模拟结果表明,级联环形腔能够很好地补偿该交错复用器的色散

Multi-wavelength fiber source using a reflection Mach-Zehnder filter and double-pass backward configuration

A new spectrum sliced multi-wavelength fiber source (MWFS) with no power loss is presented in this paper. The source is composed by a reflection Mach-Zehnder filter (RMZF) with double-pass backward superfluorescent fiber source (DPB SFS) configuration. The RMZF not only provides spectrum filtering but also provides the double-pass function. Multi-wavelength source with extinction ratios larger than 15 dB can easily be obtained over the total conventional band gain region with appropriate erbium-doped fiber (EDF) length and pump power. There is no power loss with the MWFS as compared to the original DPB SFS owning to the RMZF also provides the double-pass function. More than 50 channels of 0.57nm wavelength spacing between 1530nm-1560nm are obtained

Stable L-band superfluorescent fiber source using one pump

We first demonstrate that by inserting an appropriate section of unpumped erbium-doped fiber (EDF) in an erbium-doped superfluorescent fiber source (SFS) of double-pass backward configuration, a stable L-band SFS can be achieved. The fiber-length arrangement of unpumped fiber are shown to have significant effects on the output properties of the L-band SFS. The spectral linewidth is broadened, and the variation of mean wavelength versus pump power is eliminated to achieve a wideband and mean wavelength stable L-band SFS by optimizing the fiber-length ratio of the pumped fiber length to the total fiber length. For a 19-m-long total EDF with fiber-length ratio of 0.84, a mean wavelength stable L-band SFS with a spectral linewidth of 49.6 nm, an output power of 46.3 mW, and a mean wavelength of 1583.20 nm was experimentally achieved. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI:10.1117/1.3168643

线宽展宽L波段掺铒光纤光源特性研究

提出了一种两级级联的掺铒光纤超荧光光纤光源(SFS)的新结构,采用耦合器将一个1 480 nm半导体(LD)泵浦源按照一定的分光比对第二级进行双向泵浦,第一段光纤未泵浦。通过研究两级光纤长度的比例、耦合器的分光比对结构性能的影响,优化结构参数后线宽扩展13 nm,输出效率提高6%,并且该结构的中心波长也具有对泵浦功率不敏感的特性