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131.
在掺铒玻璃波导放大器(EDWA)的三能级速率-传输方程中,考虑两次离子交换工艺中波导掩模窗口宽度w不同所导致的抽运光、信号光模场与光强分布的不同,讨论不同w对EDWA增益特性的影响,得到光强分布的数值解.引入描述波导中抽运光和信号光的归一化光强重叠因子,对EDWA的传统近似解提出修正,得到了修正解,使其更加接近光强分布的数值解.模拟结果表明,在条波导长度为4 cm、抽运光波长为980 nm、功率为80 mW、信号光波长为1534 nm、功率为-10 dBm条件下,不同w所导致EDWA的增益差别可达297 dB.修正解的结果比传统近似解更加接近光强分布的数值解.修正解对于EDWA的理论研究、器件设计具有指导作用.
关键词:
集成光学
掺铒玻璃波导放大器
重叠积分因子
增益 相似文献
132.
采用嵌入原子势,使用分子动力学方法对金属Al不同低指数晶面的表面熔化现象分别进行了模拟.分析了熔化过程中样品结构组态的变化.模拟结果表明对于不同的自由表面,表面熔化呈现出明显的各向异性行为.Al(110)面在低于熔点的温度之下发生预熔化;(111)与(001)面都出现过热现象.与(111)面不同,(001)面发生过热现象时表面原子层为类液层,而(111)面仍然保持很好的晶格结构,即预熔化的Al(001)面在高于熔点的温度下,仍可以在很长的时间内处于相对稳定的亚稳态.由模拟得到Al的热力学熔点为950 K左右,与实验值基本符合.
关键词:
分子动力学
表面熔化
过热 相似文献
133.
针对高功率固体激光器的散热需求,设计了一种基于制冷循环的喷雾冷却系统,并对其换热性能进行研究。由于制冷系统的压缩机需要润滑,冷却液中不可避免地会混有润滑油。润滑油会对冷却液的粘度、表面张力产生影响,并可能产生油膜,从而对冷却液的换热过程产生强化或抑制。因此,通过实验研究,分析了润滑油对喷雾冷却换热性能的影响。实验结果表明,冷却液中存在润滑油,会增大冷却液流经喷嘴过程中的阻力,减小流量,但根据本系统的应用情况,可以忽略;在低热流密度时,含有一定量的润滑油更有利于热源表面温度的均匀分布,高热流密度时,2%(质量分数)的含油量对温度分布不均的影响可以忽略;润滑油的存在可以提高临界热流密度,使得系统的散热能力得到提高,更有利于其在高功率固体激光器散热领域的应用。 相似文献
134.
In this paper we provide the new criteria for a strictly generalized diagonally dominant matrix, and it proves by an example that the results of this paper extend the results in[6]. In addition, we obtain the criteria of the nonsingular M-matrix. 相似文献
135.
Yuanan Zhao Yingjian Wang Hui Gong Jianda Shao Zhengxiu Fan 《Applied Surface Science》2003,210(3-4):353-358
The effects of annealing on structure and laser-induced damage threshold (LIDT) of Ta2O5/SiO2 dielectric mirrors were investigated. Ta2O5/SiO2 multilayer was prepared by ion beam sputtering (IBS), then annealed in air under the temperature from 100 to 400 °C. Microstructure of the samples was characterized by X-ray diffraction (XRD). Absorption of the multilayer was measured by surface thermal lensing (STL) technique. The laser-induced damage threshold was assessed using 1064 nm free pulsed laser at a pulse length of 220 μs.
It was found that the center wavelength shifted to long wavelength gradually as the annealing temperature increased, and kept its non-crystalline structure even after annealing. The absorbance of the reflectors decreased after annealing. A remarkable increase of the laser-induced damage threshold was found when the annealing temperature was above 250 °C. 相似文献
136.
137.
138.
The epoxy-siloxane/Al composite coatings with low infrared emissivity for high temperature applications 总被引:1,自引:0,他引:1
Chen Hu Guoyue Xu Xingmei Shen Chunming Shao Xiaoxing Yan 《Applied Surface Science》2010,256(11):3459-3463
Low infrared emissivity coatings with good thermal resistance were prepared by using epoxy-siloxane and aluminum as adhesive and pigment, respectively. The influence of chemical composition, surface texture, roughness and thickness on the infrared emissivity was systematically investigated. The detailed results of experimental investigation indicate that the cured composite coatings could possess low emissivity value. Due to reducing infrared absorption and forming uniform and compact char construction, the infrared emissivity decreases obviously. Both the surface roughness and thickness have a critical value, respectively. Too large roughness or thickness would not contribute to the decrease of the emissivity. Moreover, the composite coatings were tested for thermal stability in air to explore the effect of high-temperature environment on the emissivity. The results indicate that the composite coatings, still possessing low emissivity after the test, exhibit favorable thermal ageing and thermal shock resistance. 相似文献
139.
In this work, optical wavelet de-noising with several different types of wavelets such as db4, coif4 and dmey wavelet was applied at the end of the 40 Gbit/s multi-span intensity-modulated fiber communication systems. The results of numerical simulations carried out in different fiber links demonstrated that the optical wavelet de-noising method could remove the random amplitude fluctuation induced by the interaction of EDFA’s ASE noise and optical fiber’s dispersion and nonlinearity. The SNR and BER curves of the optical bit sequence without and with optical wavelet de-noising in dispersion compensation fiber link were plotted to show the effectiveness of the wavelet de-noising in the fiber-optic communication systems and wavelet de-noising with demy wavelet can achieve better result than with other type wavelet. 相似文献
140.
Laser conditioning of high-reflective and anti-reflective coatings in vacuum environments 总被引:1,自引:0,他引:1
Laser conditioning effects of the dielectric mirror coatings in vacuum environments were investigated. The laser-induced damage thresholds (LIDT) in vacuum environments before and after laser conditioning were compared. It is found that laser conditioning in vacuum environments decrease the LIDT of the component. Laser conditioning effects in vacuum and atmosphere environments were also compared and investigated. The negative effects of laser conditioning in vacuum environments were discussed and analyzed with defect statistical model, energy dispersive X-ray analysis and absorption measurements. 相似文献