Long-wavelength erbium-doped fiber amplifier gain enhanced by ASEend-reflectors

We use for what we believe is the first time narrow-band end-reflectors to reduce losses through short-wavelength amplified stimulated emission (ASE) in silica-based erbium-doped fiber amplifiers operating at wavelengths above 1570 mm. The end-reflectors feed a small fraction of the ASE, up to a few tenths of a milliwatt, back into the amplifying fiber. The reflected ASE compresses the short-wavelength gain and thus reduces the ASE-losses, from, e,g., 50 mW for a launched pump power of 110 mW at 980 nm without end-reflector to 10 mW with an optimized end-reflector. We investigate possible improvements of gain (around 5 dB) and output power (up to 17 mW), and the influence of the amount and wavelength of the feedback     

1-(2,6-二溴-4-硝基苯)-3-(4-硝基苯)-三氮烯与锌的显色反应研究

研究了 1- (2 ,6-二溴 - 4 -硝基苯 ) - 3- (4 -硝基苯 ) -三氮烯 (DBNPNPT)与锌的显色反应。在表面活性剂Triton X- 10 0的存在下 ,p H=9.0— 11.0的 Na2 B4 O7- Na OH介质中 ,DBNPNPT与锌 ( )可生成橙黄色络合物。建立以 5 35 nm为参比波长 ,4 4 0 nm为测定波长的双峰双波长测定法 ,该络合物的表观摩尔吸光系数为 1.34× 10 5L· mol-1· cm-1。对葡萄糖酸锌中的锌直接测定 ,结果令人满意     

样品-窗口界面运动速度的VISAR测试技术

 介绍了与VISAR配合的加窗干涉仪测试技术。实验中分别采用样品表面和窗体表面作为信号光反射面，并用透明粘接剂粘接窗口和样品，得到厚度约为6 μm、对532 nm激光透过率不小于85%的粘接层。对窗体本身提出采用楔形的技术，有助于消除表面反射光和窗体寄生干涉对VISAR信号的干扰，从而提高信号的信噪比和测试可靠度。利用这一技术分别得到了6.5 GPa和3.61 GPa冲击压力下铜-LiF晶体窗口、LiF-LiF晶体窗口之间的界面速度变化过程。     

Robust output feedback stabilization for two-dimensional continuous systems in roesser form

This paper considers the problem of robust stabilization via dynamic output feedbackcontrollers for uncertain two-dimensional continuous systems described by the Roesser's state space model. The parameter uncertainties are assumed to be norm-bounded appearing in all the matrices of the system model. A sufficient condition for the existence of dynamic output feedback controllers guaranteeing the asymptotic stability of the closed-loop system for all admissible uncertainties is proposed. A desired dynamic output feedback controller can be constructed by solving a set of linear matrix inequalities. Finally, an illustrative example is provided to demonstrate the applicability and effectiveness of the proposed method.     

Banach空间的框架及原子分解的性质

本文利用Hilbert空间的框架理论对Banach空间的框架和原子分解的性质进行了研究,给出了Banach空间的框架和原子分解的一个充分条件,并讨论了Banach空间的框架和原子分解的关系。     

拓扑遍历映射的一些性质

本文研究拓扑遍历映射.指出对于由不可约方阵所决定的符号空间有限型子转移而言,或紧致交换群的仿射变换及线段上连续自映射而言,拓扑遍历与拓扑可迁这两个概念是一致的.同时还通过例子,指出拓扑遍历是不同于拓扑可迁与拓扑混合的概念.     

无界区域R~1上的KDV型方程的指数吸引子

本文研究了无界区域R~1上的KDV型方程,运用带权空间构造一类紧算子和算子分解的方法,得到了该方程在无界区域R~1上拥有一个指数吸引子。     

Material Growth and Device Fabrication of GaAs Based 1.3μm GaInNAs Quantum Well Laser Diodes

Material growth and device fabrication of the first 1.3μm quantum well (QW) edge emitting laser diodes in China are reported.Through the optimization of the molecular beam epitaxy (MBE) growth conditions and the tuning of the indium and nitrogen composition of the GaInNAs QWs,the emission wavelengths of the QWs can be tuned to 1.3μm.Ridge geometry waveguide laser diodes are fabricated.The lasing wavelength is 1.3μm under continuous current injection at room temperature with threshold current of 1kA/cm2 for the laser diode structures with the cleaved facet mirrors.The output light power over 30mW is obtained.     

一种新型全光纤速度干涉仪

 基于传统速度干涉仪(VISAR)和光纤速度干涉仪(AFVISAR)的特点，提出了一种由光纤和光纤耦合器组成的工作波长为532 nm的新型全光纤速度干涉仪（NAFVISAR）。该干涉仪采用多模光纤器件构成分离系统,单模光纤器件组成核心部分。由于有两路携带不同信息的光束经不同路径传输到耦合器中，当这两路光束满足干涉条件时，可利用它们的干涉场信息来调解出被测靶的信息，从而区分波面的加减速变化。用该系统进行了Hopkinson森杆一维应力加载下的入射杆端面的速度剖面测试，实测速度最大值为49.36 m/s，与理论速度的最大值50.16 m/s基本符合，实现了全光纤速度干涉仪的实用化。