Polarization control and tuning efficiency of tunable vertical-cavity surface-emitting laser with internal-cavity sub-wavelength grating
Wang Xiao-Long, Zou Yong-Gang, He Zhi-Fang, Liu Guo-Jun, Ma Xiao-Hui §
       

The schematic diagram of a trapezoidal sub-wavelength grating. Λ is the period, H is the ridge height, and θ is the inclination angle.