Narrow Linewidth Tm^3＋-Doped Large Core Fiber Laser Based on a Femtosecond Written Fiber Bragg Grating

A diode laser （LD） clad-pumped narrow linewidth all-fiber Tm^3＋-doped fiber laser is reported with a maximal output power of 27W at 1.947μm. By successively splicing an LD pigtail fiber, a single-mode Tm^3＋-doped fiber, and a multi-mode Tm^3＋-doped fiber, the fiber laser has 70pm narrow linewidth output, and a high slope efficiency of nearly 47.5% with respect to the launched pump power. The high reflectivity fiber Bragg gratings, which are directly written into the single-mode Tm^3＋-doped fiber core by the 800nm femtosecond pulsed laser, act as the high reflectivity coupler. The output laser has diffraction-limited beam quality with a factor M^2 of 1.29, when the output laser power is nearly 27W.     

环形子孔径拼接干涉检测非球面的建模与实验

为实现球面波干涉检测非球面镜片,得到非球面镜片的完整面形信息,提出了基于标记的Givens变换,实现环形子孔径的精确定位和消旋转的处理.利用求解目标函数最小值的方法精确求解拟合波面以对子孔径数据进行处理,建立了全局优化拼接数学模型.对外径150 mm,内径100 mm的抛物面镜片进行三孔径拼接检测实验,均方根值为0.053 λ.对比补偿器法得到的全口径干涉检测结果均方根值△Wrms=0.052 λ,相对误差为1.92%.实验结果表明,该方法稳定可靠,降低了传统的环形子孔径拼接干涉检测方法中对导轨的高精度要求.     

Ld-Clad-Pumped All-Fiber Tm^3＋-Doped Silica Fiber Laser

The CW 39.4 W all-fiber LD-clad-pumped Tm^3＋-doped fiber laser output is reported with a slope efficiency of 34% in respect to the pump power. The all-fiber laser is made up by progressively splicing the pigtail fiber, matched FBG fiber and Tin-doped fiber. The reflective FBG and Tm-doped fiber end fresnel reflection build up the laser resonance cavity. Due to the multi-mode FBG as the reflective mirror, the output laser spectrum is multi-peaks at high power output, whereas the total spectrum width is less than 2nm at nearly 1.94μm.     

Analysis and compensation of thermal lens effects in Tm：YAP lasers

The thermal lens effects in Tm：YAP laser are analyzed by solving the Poisson equation with finite difference method. The thermal focal lengths measured are in the range of 40-90 mm at the pump power of 16-34 W, consistent with the simulation results. The temperature contribution coefficient （the linear coefficient between the maximum temperature in the laser crystal and the pump power） of 1.19 K/W is also obtained. The convex lens and plano-concave mirror thermal lens compensation methods are proposed and applied to a high power pumped Tm：YAP laser.     

一种靶机红外辐射特性增强技术研究

为了在外场试验中检验红外制导武器系统的工作性能,需要使用靶机红外增强装置实现对真实目标红外辐射特性的模拟。介绍了一种利用光学方法实现靶机红外辐射增强和目标辐射特性模拟的技术。使用高亮度红外光源作辐射源,通过对光学系统的控制,在实现红外辐射增强的同时,可模拟不同距离和方向的红外辐射强度特性。通过建模对所模拟目标的红外辐射强度及辐射方向特性进行了分析,并以此为设计依据设计了光学系统。实现了对最大红外辐射强度为1600W/sr的目标辐射方向特性的模拟。