端面反射率的波长特性对外腔半导体激光器调谐范围的影响

端面镀增透膜的激光二极管构成的光栅外腔激光器（ECLD）中，考虑到镀膜端面剩余反射率对波长的依赖关系以后，利用等效腔法导出了该激光器阈值载流子密度随波长变化的解析表达式，以此为出发点，讨论了增透膜反射率极小位置对调谐范围的影响。结果表明，除了增大剩余反射率工和降低剩余反射率能够提高调谐范围这一明显结论这外，在镀膜工艺确定的情况下，即假定剩余反射率带宽和剩余反射率极小值变化不大时，通过控制剩余反射率极小值所对应的波长相对于镀膜前增益峰的偏移量，可进一步拓宽波长调谐范围。

Effect of Wavelength Dependence of Reflectivity at AR-Coating Facets on Tuning Range of External-Cavity Semiconductor Lasers

Wavelength dependence of reflectivity at AR coating facets has been taken into account to study the wavelength tuning range of the external cavity semiconductor lasers. By applying the equivalent cavity method, an analytical expression for the threshold carrier density varied with wavelength has been derived. Analysis shows that the deviation between the wavelength of minimum reflectivity at the AR coated facets and that of the gain peak before AR coating is a key parameter to increase wavelength tuning range.