Lau cavity and phase locking of laser arrays

The Lau cavity is the self-imaging cavity with a phase corrector under the Lau reimaging condition. The author proposes the use of the Lau cavity to utilize both the Talbot and the Lau effects for phase locking one-dimensional and two-dimensional diode-laser arrays into a single-lobe coherent beam. Analyses on the self-reproducing of a coherent lasing field and the reimaging of initial incoherent radiation are given.

Phase-locking of two large-core fibre lasers with 60W of coherent output power

A phase-locking fibre laser array with up to 60 W of coherent output power based on two large-core fibre is reported. The slope efficiency of the in-phase mode is 37%. For two cases of spacings between the cores, steady high-contrast interference stripes are observed. When the whole system operates under a high pump power level, no thermal effects for the spatial filter have been observed, which means that we can increase the coherent output power further by increasing the individual fibre laser power.

Experimental demonstration of phase locking of a two-dimensional fiber laser array using a self-imaging resonator

Phase locking of a two-dimensional fiber laser array is experimentally demonstrated by using a self-imaging resonator and a spatial filter. The stable beam profiles of in-phase mode and out-of-phase mode are observed by controlling the position of spatial filter. The phase locking fiber array with in-phase mode has produced 26 W coherent output. An antisymmetric eigenmode is also observed in our experiments. The phase locking is not sensitive to power variations among the pump beams and the configuration has the ability to repair a missing element. (C) 2008 American Institute of Physics.

Phase locking of fibre lasers by self-imaging resonator

Experimental demonstrations of the use of a self-imaging resonator in the phase locking of two fibre lasers are presented. The output power of the phase-locked fibre laser array exceeded 2 W Successful attempts of phase locking show that the fibre laser array is not only capable of producing high Output Power but also large on-axis intensity by this method.

光纤激光阵列锁相和孔径装填技术研究进展

介绍了几种典型的激光阵列锁相和孔径装填技术,重点综述了国内外光纤激光阵列锁相和孔径装填技术的研究进展,最后对高功率高光束质量激光光源的应用和发展前景进行了展望。

超大功率二维半导体激光列阵并路自适应稳模技术

半导体列阵量子效率高,输出波长范围涵盖570～1600nm,工作寿命可达数百万小时,叠层列阵可提供超高功率激光输出,在工业、医学等很多领域具有非常广阔的应用前景。但列阵在自由运行时,各发光单元发出的光是不相干的,输出质量差,采用1/4Talbot外腔镜耦合技术,列阵实现了空间锁相最高阶超模,然而唯有基超模远场分布是中心单瓣结构,输出接近衍射极限。为得到最小谱宽、最小发散角、最大功率密度输出,必须将外腔镜倾斜β=λ/2d(λ为工作波长,d为列阵周期),这使得仅有基超模光能成像于发光单元内而被允许振荡。应用此

位相锁定来自同一侧面抽运Nd：YAG板条的两束激光

实验研究了腔内位相锁定来至一LAD侧面抽运的Nd：YAG板条的两束激光，输出镜面出现干涉条纹，获得1.13W的相干光，其组束效率达到64.9%，相干度约60%。实验中发现只需要一根作为滤波的金属丝放在离输出镜合适的位置都就能有效稳定干涉条纹，金属丝引起的损耗低于8%。

两个光纤激光器的相位锁定及高相干功率输出

研究了两个光纤激光器的相位锁定及其相干输出。将两个光纤激光器的输出耦合进一个自成像共振腔，然后利用一个空间滤波器进行模式选择。自成像共振腔由两个焦距为8mm的准直透镜、一个焦距为500mm的傅里叶透镜和一个耦合输出镜组成。滤波器由两根20μm的铂金线组成，并放置在耦合输出镜面上。实验中，观测到光束截面图样具有高对比度的干涉条纹。输出镜反射率在50％和30％情况下，分析了单个激光器和激光器阵列的斜率效率。在总抽运功率为60W时，获得了18．3W的高相干功率输出。稳定的相位锁定是由于激光器阵列具有能适应光程长

两根掺镱大芯双包层光纤激光器获得113W同相输出功率

利用一个自成像共焦腔和一个空间滤波器实现了两掺Yb大芯光纤激光器的位相锁定。观测到稳定的具有高对比度的干涉条纹。相干条纹的对比度为59%，而非相干时对比度为6%。中心条纹的宽度与理论计算结果吻合得很好。对同相模式而言，位相锁定激光器阵列输出达到113W，对应的斜率效率为38.5%。

High power coherent beam combination from two fiber lasers

Phase locking of two fiber lasers is demonstrated experimentally by the use of a self-imaging resonator with a spatial filter. The high-contrast interference strips of the coherent beam profile are observed. The coherent output power of the fiber array exceeds 12W and the efficiency of coherent power combination is 88% with pump power of 60W. The whole system operates quite stably and, for the spatial filter, no thermal effects have been observed, which means that we can increase the coherent output power further by this method. (c) 2006 Optical Society of America

Spectral hole-burning of Eu3+: Y2SiO5 crystal at 579.62 mm

By using an Ar+ ion laser, a tunable Rh 6G dye laser(Linewidth : 0.5 cm(-1)) and a Coherent 899-21 dye laser as light sources and using a monochromator and a phase-locking amplifier, the optical properties of Eu3+ : Y2SiO5 crystal were detected. Persistent spectral hole burning (PSHB) were also observed in (5)Do-(7)Fo transition in the crystal at the temperature of 16 K. For 15 mW dye laser (Wavelength : 579.62 nm) burning the crystal for 0.1 s a spectral hole with about 80 MHz hole width were detected and the hole can been keep for longer than 10 h.

Fast Locking and High Accurate Current Matching Phase-Locked Loop

In this paper, a charge-pump based phase-locked loop (CPLL) that can achieve fast locking and tiny deviation is proposed and analyzed. A lock-aid circuit is added to achieve fast locking of the CPLL. Besides, a novel differential charge pump which has good current matching characteristics and a PFD with delay cell has been used in this PLL. The proposed PILL circuit is designed based on the 0.35um 2P4M CMOS process with 3.3V/5V supply voltage. HSPICE simulation shows that the lock time of the proposed CPLL can be reduced by over 72% in comparison to the conventional PILL and its charge pump sink and source current mismatch is only 0.008%.