窄脊型波导半导体激光器偏振与横模关系研究

Study on the relationship between polarization and transverse modes of narrow ridge waveguide semiconductor lasers

基于有效折射率法建立了窄脊型波导数值计算模型,通过实验研究了InGaAs量子阱窄脊型波导半导体激光器偏振特性与横模之间的关系。根据理论计算,脊型波导中类TM模式在慢轴方向的有效折射率差更大,类TM模式的限制因子比类TE模式的限制因子更大、更容易出现慢轴高阶模式;而随着脊型波导的高度增加,快轴高阶模式被截断,类TE00模式的限制因子逐渐增加至与类TM00模式相近,慢轴高阶模式因其大的散射损耗被抑制,理论上可实现高偏振度、高光束质量激光输出。在实验方面,利用量子阱材料的增益偏振特性,通过脊型高度与宽度的设计,制备了高偏振度、基横模的窄脊型波导半导体激光器。

A numerical calculation model of the narrow ridge waveguide was established based on the effective refractive index method.The relationship between the polarization characteristics and the transverse mode of the InGaAs quantum well narrow ridge waveguide semiconductor laser was studied experimentally.According to theoretical calculations,the effective refractive index difference of the TM-like mode in the ridge waveguide is larger in the direction of the slow axis.The confinement factors of the TM-like mode are larger than those of the TE-like mode,and the slow-axis high-order mode is more likely to appear.As the height of the ridge waveguide increases,the fast-axis high-order modes are truncated,and the confinement factor of the TE00-like mode gradually increases to be similar to that of the TM00-like mode.The slow-axis high-order mode is suppressed due to its large scattering loss,theoretically achieving high polarization,and near diffraction limit beam-quality laser output.In terms of experiments,a narrow ridge waveguide semiconductor laser with a high polarization extinction ratio and a fundamental transverse mode was fabricated by the gain polarization characteristics of quantum well materials and by designing the height and width of the ridge.