外腔中半导体二极管激光阵列的高阶侧模锁定

 理论分析了外腔较短情况下,宽条半导体二极管激光阵列（LDA）高阶侧模相位锁定的可能性,观察了包含主、旁瓣结构的多侧模远场光强分布。从实验记录结果可以看出,在旁瓣中出现了标志锁相的峰、谷结构,而且该结构的调制度明显高于主瓣中的峰、谷结构的调制度,结果表明：在外腔较短情况下,LDA高阶侧模相位锁定的现象是存在的。     

外腔中半导体二极管激光阵列的高阶侧模锁定

理论分析了外腔较短情况下,宽条半导体二极管激光阵列（LDA）高阶侧模相位锁定的可能性,观察了包含主、旁瓣结构的多侧模远场光强分布。从实验记录结果可以看出,在旁瓣中出现了标志锁相的峰、谷结构,而且该结构的调制度明显高于主瓣中的峰、谷结构的调制度,结果表明：在外腔较短情况下,LDA高阶侧模相位锁定的现象是存在的。     

Theoretical analysis on phase-locking properties of a laser diode array facing an external cavity

External coupling model has been used to describe the output field of a laser diode array (LDA) phase-locked with an external cavity. The analytical solution for the coupling matrix equation of the phase-locked system has been obtained. The dependencies of the threshold gain, g_j of the system mode on the residue reflection of the front facet, r_f and round trip external cavity lengths, L have been discussed. The working lengths of the external cavity for stably phase-locking the LDA of different residual reflectivities have been calculated.     

外腔锁相宽发光区二极管激光列阵研究

利用简单的外腔,实现了具有宽发光区的商用半导体二极管激光列阵(DLA)的外腔锁相。光谱测量表明,DLA的谱宽由自由运行时的1.9 nm压缩到了0.16 nm,峰值波长由803.8 nm调整到805.5 nm;实测远场光瓣间角距等于1.6 mrad,即波长与发光单元间距之比,表明列阵运行在基超模(或最高阶超模);峰谷结构调制度大于0.8。观察表明,外腔长度在1/10~1/6泰伯距离内变化时,锁相均能实现。实验事实表明锁相是交叉注入锁定的结果。利用半导体激光注入锁定理论,定性分析了外腔DLA由自由振荡向锁相过渡的过程,预言了锁相场波长应出现在自由运行DLA光谱长波端,实验也证实了这一事实。     

一种实现光纤激光器高功率输出的方法

介绍了一种实现光纤激光器高功率输出的新方法——采用螺旋芯光纤，这种光纤是在光纤制作过程中按照一定的弯曲半径使纤芯呈螺旋状排布在光纤包层中。介绍了这种螺旋芯光纤的原理和其提高输出功率的能力，以及目前的理论与实验研究现状。基于该光纤，提出了一种光纤激光器相干合成新思想。     

外腔锁相半导体激光器列阵的稳态分析

给出了描述半导体激光器列阵(LDA)稳定状态的非线性方程组。对非线性方程组进行了分析,研究了LDA在稳态运行时的特性。分别分析了LDA在同相模运行和反相模运行时,载流子浓度、振荡频率以及光子数密度与自由运行时相比较所发生的变化。     

二极管激光阵列在Talbot外腔中同相模的选择

从理论和实验上对二极管激光阵列在Talbot外腔中的锁相进行了研究。在同相模和异相模近场分布的基础上,利用1维情况下的菲涅耳衍射公式计算了其远场分布。根据同相模和异相模在Talbot腔中的分布特性,采用1/2 Talbot腔并将外腔镜倾斜一个角度a的方法既能选择同相模,又能使模式的功率损耗最小。二极管激光阵列芯片采用CD金刚石材料,“三明治”结构对其进行封装,明显地减小了阵列的“smile”效应。在实验中实现了二极管激光阵列同相模的锁相输出,远场单瓣模的半高全宽为0.11 mm。     

Spectral beam combining of a broad-stripe diode laser array in an external cavity

The outputs from an 11-element, linear diode laser array with broad stripes have been beam combined into a single beam with a beam quality of ~20x diffraction limited in the plane of the junction. This beam combining was achieved by use of a common external cavity containing a grating, which simultaneously forces each array element to operate at a different, but controlled, wavelength and forces the beams from all the elements to overlap and propagate in the same direction. The power in the combined beam was 50% of the output from the bare laser array.     

外腔锁相中二极管激光阵列发光单元间耦合系数分析

推导了外腔中二极管激光阵列各发光单元之间的耦合系数,结果表明：增加外腔长度有利于减小各阶耦合系数的差别和实现“并联耦合”,但是外腔的作用效果下降;降低阵列前端面的反射系数,有利于实现外腔锁相;外腔锁相中并联耦合的单元数越多,激光二极管阵列前端面的反射系数的允许值越小。     

Talbot外腔压窄线阵大功率半导体激光器输出谱宽

线阵半导体激光器（LDA）内部发光元周期排列,基于Talbot效应,改进传统Littrow外腔窄线宽系统,在Littrow外腔中置入反射率为20%平平镜构成Talbot外腔以进一步窄化激光器输出谱宽,并将外腔窄线宽输出通过铷池进行吸收实验。实验结果表明：铷池对Tablot外腔输出吸收系数比Littrow外腔吸收系数相对提高42.9%,说明Talbot外腔能有效提高外腔输出谱宽的均匀性,提高半导体激光器泵浦效率。     

二极管激光阵列在Talbot外腔中同相模的选择

 从理论和实验上对二极管激光阵列在Talbot外腔中的锁相进行了研究。在同相模和异相模近场分布的基础上,利用1维情况下的菲涅耳衍射公式计算了其远场分布。根据同相模和异相模在Talbot腔中的分布特性,采用1/2 Talbot腔并将外腔镜倾斜一个角度a的方法既能选择同相模,又能使模式的功率损耗最小。二极管激光阵列芯片采用CD金刚石材料,“三明治”结构对其进行封装,明显地减小了阵列的“smile”效应。在实验中实现了二极管激光阵列同相模的锁相输出,远场单瓣模的半高全宽为0.11 mm。     

体布拉格光栅外腔实现激光二极管阵列同相模输出

采用体布拉格光栅作为商用二极管激光阵列外腔,通过将每个单元发出的光反馈回相邻单元实现了外腔锁相。采用这种方法对发光单元宽度为100 μm、周期为200 μm,由49个单元构成的二极管阵列进行了外腔锁相实验,在远场获得了高光束质量、窄带宽的稳定输出。二极管激光阵列自由运转下功率为15 W,经外腔锁相后输出功率为3.67 W,对应光束远场发散角1.47 mrad, 光谱的峰值半宽由1.7 nm压窄到0.17 nm。     

外腔锁相二极管激光列阵的超模

 利用耦合理论推导了通过外腔反馈实现锁相运行的激光二极管列阵所满足的本征值方程。在忽略非相邻单元间耦合的串联运行方式下，解析求解了包括端面反射的列阵方程的本征值。求出了各阶超模的近场分布，并得到了考虑单个发光单元影响时的远场分布，具体为：当列阵运行于基超模时，近场各个单元间的光场同相，在远场中心位置出现光强主极大；而在其它高阶模式，近场各个单元间光场不同相，远场光强主极大出现在中心位置两侧；远场总体受到单个发光单元近场分布函数的调制。     

Phase-locking of a multi-channel radial array CO2 laser

A theoretical analysis of phase-locking in a multi-channel radial array CO₂ laser is presented. The concepts are based on the theories of injection phase-locking and matrix optics. The mutual optical coupling occurring within the central region is demonstrated by theoretical deduction. Interrelated graphs of the coupling coefficient and the distance between the coupling position and the cavity mirror are calculated by numerical simulation. The results of the analysis are in accord with experimental results.     

半导体激光器列阵在外腔下的光谱特性

使用普通高反镜作为19个单元的半导体激光器列阵(LDA)的外腔,通过调节高反镜的位置和角度,使LDA发出的光反馈回有源层,从而压窄了输出光谱并降低了LDA的阈值电流.实验中,运行于外腔下的LDA在不同的驱动电流下的输出光谱均被压窄到了原来的1/10左右,阈值电流从7 A降到了5.5 A,并且在9 A的偏置电流下输出功率提高了2倍.     

利用外腔改善半导体激光器列阵的远场特性

采用一个由快轴准直透镜和一个高反射率平面镜组成的简单外腔,在腔长为几个cm时实现了半导体激光器列阵中部分单元的锁相运行;DLA远场出现了3个瓣,每瓣发散角为10 mrad左右,对比度为50%;通过控制部分单元的输出,可以抑制旁瓣的能量.     

Hyperboloid cylinder-plane lens for shaping laser diode array beam

A high coupling efficiency, simple structure refractive lens was designed; a hyperboloid cylinder-plane lens was proposed to reduce the divergence angle of the laser diode array beam in the fast axis direction. Based on the ray-tracing method, the shape of the input refractive surface of the designed lens is determined by numerical analysis, and designed as aspherical profile in one direction. When the beam from source point reaches the input surface of the lens, it is refracted and becomes a parallel output beam in the fast axis direction. The expressions for describing the irradiance behind the lens are also derived.     

闪耀光栅阵列用于半导体激光器列阵光束整形

介绍了半导体激光器列阵的光束整形理论,设计并制作了由两个闪耀光栅阵列构成的整形光学系统,理论计算表明该系统能将激光器快、慢轴方向的光参数积变为5.7 mm·mrad和8.9 mm·mrad.在整形实验中测得变换后快、慢轴方向的光参数积分别为12 mm·mrad和9.5 mm·mrad,经透镜聚焦后能够实现与芯径200 μm,数值孔径0.22的光纤耦合.     

外腔锁相中二极管激光阵列发光单元间耦合系数分析

 推导了外腔中二极管激光阵列各发光单元之间的耦合系数，结果表明：增加外腔长度有利于减小各阶耦合系数的差别和实现“并联耦合”，但是外腔的作用效果下降；降低阵列前端面的反射系数，有利于实现外腔锁相；外腔锁相中并联耦合的单元数越多，激光二极管阵列前端面的反射系数的允许值越小。     

The in-phase mode selection of a high-power diode laser array by a talbot cavity with an amplitude compensator

The in-phase mode selection with the amplitude compensator at a high current (I > 20 A) was analyzed theoretically and achieved experimentally in an external Talbot cavity, of length L = Z_T/4. The used linear array consisted of 49 wide-aperture diodes with a diode emitter aperture a = 100 μm and a center to center period d = 200 μm. Increasing the output radiation intensity in the far-field central lobe was demonstrated, and the power of the multi-lobes was 1.57 W without the amplitude compensator and then it concentrated on the single lobe was 0.96 W by inserting the amplitude compensator in the external cavity when the injection current was 25 A. The far-field divergence of the phase locked radiation was 1.80 mrad, and the spectral FWHM of the output radiation was suppressed from 1.7 nm to 0.15 nm.