Theoretical modelling of the effect of photon lifetime on the output dynamics of Er-doped distributed feedback fibre lasers

By employing a simple model of describing three-level lasers, we have theoretically investigated the effect of photon lifetime on the output dynamics of Er-doped distributed feedback fibre lasers. And based on the theoretical analysis we have proposed a promising method to suppress self-pulsing behaviour in the fibre lasers.

Properties of convergence of a class of iterative processes generated by sequences of self-mappings with applications to switched dynamic systems

This article investigates the convergence properties of iterative processes involving sequences of self-mappings of metric or Banach spaces. Such sequences are built from a set of primary self-mappings which are either expansive or non-expansive self-mappings and some of the non-expansive ones can be contractive including the case of strict contractions. The sequences are built subject to switching laws which select each active self-mapping on a certain activation interval in such a way that essential properties of boundedness and convergence of distances and iterated sequences are guaranteed. Applications to the important problem of stability of dynamic switched systems are also given.

Analysis on a new type magneto-optical disk for blue lasers

The conventional TbFeCo magneto-optical (MO) medium has a relatively smaller Kerr rotation angle in the blue region than in the red. With the recording wavelength gradually moving to the short wavelength, if TbFeCo is still used as recording medium, the conventional MO disk structure must be optimized to get a larger carrier to noise ratio (CNR). Sabi et al. have found that adding a metal layer attached to the TbFeCo film as thermal control layer is a useful way to get a high CNR. In this paper, we proved this through calculation, and carried out optimization of the new type of disk. Calculation results showed that the new structure is useful in preventing an excessive temperature increase, and has a better thermal response. (c) 2005 Elsevier B.V. All rights reserved.

放大自发辐射对全固态激光器调Q性能的影响

为定量分析放大自发辐射（ASE）对调Q激光器性能的影响，在调Q激光速率方程中引入放大自发辐射项。并在合理的近似下求解，给出了激光二极管（LD）端面抽运电光调Q运转的固体激光器反转粒子数的建立过程，分析了放大自发辐射对激光上能级储能效率的影响及考虑放大自发辐射时调Q激光器输出脉冲宽度和脉冲能量随抽运功率的变化关系。结果表明，由于放大自发辐射的存在，上能级储能效率降低，且在一定的抽运功率下，调Q输出脉冲宽度变宽，脉冲能量下降。用LGS（La3Ga5SiO14）晶体作电光调Q元件，在激光二极管抽运的Nd：YVO

拱形激光二极管侧抽运Nd∶YAG固体激光器的实验研究

详细阐述了同心抽运、同心冷却的激光二极管紧包侧抽运Nd：YAG激光器的实验研究工作。这种抽运结构使晶体内的增益场与谐振腔基模实现了良好的匹配，易于得到良好的光束质量和大能量输出，基模提取效率高。模拟分析了晶体内的增益场以及横截面内的温度分布，从不同角度探讨了激光二极管的温度特性对器件工作的影响。研究了晶体的热致退偏效应对器件调Q工作的影响．并且初步探讨了不同腔长、不同腔型下器件的工作情况，这些实验结果对进一步优化使用这种抽运结构有指导意义。所设计的激光器在工作频率6Hz时．得到了斜效率为44．3％的多模调

调Q双包层光纤激光器研究新进展

综述了近几年来在高能量输出（毫焦）、高重复频率（千赫兹）、纳秒级脉冲输出的调Q光纤双包层光纤激光器研究的最新进展，包括饱和吸收体和受激布里渊散射被动调Q、声光和电光主动调Q等，并分析各自的特点。最后讨论了国内外调Q双包层光纤激光器的研究现状和发展前景