高功率半导体激光器线阵列的波长锁定技术

高功率半导体激光器光谱随温度和工作电流的变化比较大，光谱线宽比较宽，这些缺点直接限制了其实际应用。因此，高功率半导体激光器波长稳定技术的研究是激光领域的一个重要研究方向。对波长稳定技术进行研究。实验用体布拉格光栅（VBG）作为反馈元件与高功率半导体激光器线阵列，构成可以对其波长进行锁定的外腔激光器。分析了外腔激光器的波长锁定效果与高功率半导体激光器工作电流、冷却温度、工作电流的占空比和“smile”现象等因素的关系。研究结果表明，高功率半导体激光器的工作电流、冷却温度、工作电流的占空比会影响其激射波长，当激射波长与VBG的布拉格波长差值小于3．0nm时，可以得到较好的波长锁定效果，而阵列本身的“smile”现象对其波长锁定的影响不大。

Line-width reduction of a laser diode array using an external cavity with two feedback mirrors

A novel Littman-Metcalf external cavity laser diode array with two feedback mirrors is introduced. The line-width broadening effect caused by smile can be reduced by the novel external cavity. At the drive current of 16A, the line-width is narrowed to 0.1nm from free-running width of 1.6nm with output efficiency of 84%.

激光二极管阵列的窄线宽、可调谐输出

外腔反馈的激光二极管阵列(LDA)可获得窄线宽、可调谐的光谱输出。外腔由快轴准直镜、准直光学系统和闪耀光栅组成。由于阵列中各发光单元的排列弯曲导致不同波长的光原路返回,引起谱线展宽,在输出光路中加入光谱滤波器,使激光二极管阵列的线宽进一步窄化。这样,激光二极管阵列的输出光谱由自由运转时的2 nm压缩到0.12 nm,在恒定温度23 ℃时,实现了激光在806～818 nm的调谐,调谐范围达12 nm。

Beam collimation of high-power laser diode array with graded-index fiber lens array

Graded-index (GRIN) fiber lens arrays are fabricated from commercial GRIN fibers to collimate a high-power laser diode array. The beam divergence angles are reduced to 4.2 and 14.7 mrad in the fast and slow axes, respectively. The influences of smile and fluctuation in fiber length are discussed. Using an aspherical focal lens system, about 74% power can be launched into a fiber with a numerical aperture (NA) of 0.22 and a core diameter of 400 mu m. (c) 2008 Society of Photo-Optical Instrumentation Engineers.