2.5～4.4Gb／s光纤无中继传输实验系统

本文报导在４×６２２Ｍｂ／ｓ）×１６０ｋｍ等三个常规单模光纤无中继传输实验系统，以及４．３５４Ｇｂ／ｓ×２００ｋｍ常规单模光纤传输实验系统方面的研究成果．带有掺饵光纤功放的高稳定度光发射机输出功率分别＞＋４ｄＢｍ／信道（４×６２２Ｍｂ／ｓ）和１１ｄＢｍ（单路２．５Ｇｂ／ｓ），频率稳定度分别优于６×１０－６和４．１×１０－６．带有掺铒光纤前放的四路光接收机灵敏度达到－４６．８ｄＢｍ（６２２Ｍｂ／ｓ，ＮＲＺ２２３－１ＰＲＢＳ）和－３９．５ｄＢｍ（４×２．５Ｇｂ／ｓ，ＮＲＺ２２３－１ＰＲＢＳ）．系统各信道误码率分别优于４×１０－１２～４×１０－１５．     

Optimization of holey fiber for dispersion compensation

Hermite-Gaussian functions were used to calculate the dispersion of holey fibers, when pitch was more than 0.6 μm, there was dispersion inflexion at 1.55 μm (wavelength), and the relation of the dispersion inflexion versus fiber structure was given. Calculations show that the dispersion of holey fiber could reach -2300 ps/(nm·km), or they could compensate (to within ±4%) the dispersion of 120 times of their length of standard single mode fiber over a 100-nm range.     

Acoustic longitudinal mode coupling in w-shaped Al/Ge Co-doped fibre

This paper proposes a novel fibre structure aiming at distributed temperature and strain sensing. Utilizing Al₂O₃ and GeO₂ as dopants to form a w-shaped acoustic waveguide, it realizes modal coupling between longitudinal acoustic modes of its inner and outer core layers, leading to a dual-peak or multi-peak Brillouin gain spectrum. The relationship between the acoustic mode coupling properties and the fibre materials, doping concentrations and structural parameters are investigated, showing that the positions of mode coupling points in acoustic dispersion curves and the coupling intensities can be designed flexibly. A specific fibre design for the discriminative sensing of temperature and strain under a pump wavelength of 1.55 μm is given. The responses of its Brillouin gain properties on temperature and strain are analysed theoretically, demonstrating its potential for distributed fibre Brillouin sensing.     

Erratum： Experimental Study on Preparation Efficiency of Microstructured-Fiber Based Heralded Single-Photon Source at 1.5 μm [Chin. Phys. Lett. 26（2009）034206]

As the definition in the Letter, the preparation efficiency should be calculated according to Eq. （2）. However, the data in Fig. 4 were not divided by ηΩSPD2 = 0.15, while all the pertinent discussion is correct. We correct this mistake and show the revised figure here.     

Fluid Sensor Based on Transmission Dip Caused by Mini Stop-Band in Photonic Crystal Slab

We propose a fluid sensor based on transmission dip caused by mini stop-band in photonic crystal slabs. Simulation results show that this novel type of sensors has large detective range （more than 1.5） and relative high sensitivity （4.3×10^-5 in certain conditions）. The central frequency and bandwidth of the mini stop-bands depend on the structure parameters of PC waveguides, which makes it possible to optimize the detective range and detective sensitivity.     

Zero-Dispersion Slow Light with Wide Bandwidth in Photonic Crystal Coupled Waveguides

By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide （W2） and the hole radii of the coupling region （r＇） will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity vg in incident waveguide can be achieved. In particular, proper W2 and r＇ can lead to the lowest vg of 0.0085c at 1550 nm with wide bandwidth of 202 GHz for zero dispersion.     

抽运饱和及信道间受激拉曼散射效应对反向抽运分布式光纤拉曼放大器增益谱的影响

在宽带密集波分复用 (DWDM )系统中 ,后向抽运分布式光纤拉曼放大器 (B DFRA)会引入在小信号条件下无需考虑的两种效应 :抽运饱和效应 (PS)使拉曼增益减小 ;拉曼放大使信道间受激拉曼散射 (SRS)效应增强 ,产生附加拉曼倾斜效应 (ART)。将后向抽运分布式光纤拉曼放大器的增益谱分解为拉曼抽运的放大作用和信道间受激拉曼散射效应产生的倾斜作用 ,通过对各种工作条件下实际后向抽运分布式光纤拉曼放大器增益谱的优化计算 ,研究了抽运饱和效应和附加拉曼倾斜效应对后向抽运分布式光纤拉曼放大器增益谱的影响。计算发现抽运饱和效应取决于信道输出功率 ,附加拉曼倾斜效应由信道输入功率和输出功率共同决定 ,进而通过抽运饱和效应和附加拉曼倾斜效应的大小可以将后向抽运分布式光纤拉曼放大器的工作条件划分为三个区域 ,并讨论了不同工作条件下后向抽运分布式光纤拉曼放大器的简化分析方法     

拉曼+EDFA宽带混合光放大器的实现和设计优化

基于对增益和噪声特性的分析,本文实现了长距离宽带传输系统中由分布拉曼放大器和掺铒光纤放大器中组成的宽带混合放大单元,并提出了混合放大器进行优化设计的方法,特别指出适当调整拉曼放大器和掺铒光纤放大器的增益谱可以实现噪声谱的平坦.     

用于气体痕量检测的中红外空心布拉格光纤

布拉格光纤是一种一维光子晶体带隙导引光纤.针对布拉格光纤在气体痕量检测领域的应用,设计了传输波段中心波长位于中红外波段的半导体玻璃/有机聚合物基空心布拉格光纤.通过预制棒熔拉法,制备出了中红外空心布拉格光纤的样品.传输谱和弯曲特性测试表明布拉格光纤样品具有两个明显的传输波段,体现了带隙导光的特征.低阶传输波段的中心波长为4.4μm.     

熔烧温度对双锥光纤光学特性的影响

实验研究了熔烧温度对双锥光纤光学特性的影响。结果表明，熔烧温度影响输出功率随拉伸长度振荡的曲线形状及调制度。为获得一定的透过谱周期，所需的振荡次数随熔烧温度的升高而减小