Design of high refractive index contrast subwavelength grating reflector for 940 nmVCSEL

A high-refractive-index contrast subwavelength grating (HCG) for 940 nm GaAs-based VCSEL is reported. The reflector is composed of GaAs and AlQ(x). The effects of the grating parameters of TE-HCG on refractivity are discussed in detail. And the structural characteristics of TE-HCG and TM-HCG are analyzed, especially the influence of their topography errors on the high reflection band. The 940 nm TE-HCG has a large reflection bandwidth of up to 97 nm with its reflectivity for TE incident light more than 99. 5%, and the ratio of Ratio of high reflection band to central wavelength is more than 10%. But for TM incident light its reflectivity is less than 90%. It is worth mentioning that the VCSEL with such a TE-HCG can be prepared by one-time epitaxial growth technology, which helps to improve the performance of the device. Furthermore, it greatly reduces the manufacturing difficulty and cost of a VCSEL.