光纤光栅外腔半导体激光器输出谱的射线法研究

Investigation on the output spectrmn of fiber grating external cavity semiconductor lasers using ray tracing method

本文采用射线法,计及增益随波长的变化,首次导出了光纤光栅外腔半导体激光器(FGESL)输出谱的表达式。利用该表达式,结合载流子速率方程,对FGESL输出谱的精细结构进行研究。研究结果表明:光纤光栅外腔将引起位于反射带宽附近波长处能量分布发生变化,在反射带宽内出现多峰结构,峰的数目与外腔长度有关;随着电流的增大,FGESL的输出功率和边模抑制比总体呈现上升的趋势,上升过程中存在波动,波动的幅度和频率随着前端面反射的减小而减小。

In this paper, using the ray tracing method, after considering the gain distribution with wavelength, the expression of the output spectrum of the fiber grating external cavity semiconductor laser （FGESL） has been deduced firstly. Combining with carrier rate equation, the fine structure of output spectrum has been investigated, The results show that, near the reflective band width of grating, fiber grating external cavity will result in energy distribution to vary seriously, therne ninny, peaks and the number of peak is related to the lengths of external cavity. With the increase of the bias current, the output power and side - mode suppression ratio of EGSEL tend to increase accompanying with fluctuation, and the fluctuation will weaken with the decrease of the reflectivity of the front facet.