Vertical cavity surface emitting laser transverse mode and polarization control by elliptical holes photonic crystal

The polarization of traditional photonic crystal (PC) vertical cavity surface emitting laser (VCSEL) is uncontrollable, resulting in the bit error increasing easily. Elliptical hole photonic crystal can control the transverse mode and polarization of VCSEL efficiently. We analyze the far field divergence angle, and birefringence of elliptical hole PC VCSEL. When the ratio of minor axis to major axis b/a=0.7, the PC VCSEL can obtain single mode and polarization. According to the simulation results, we fabricate the device successfully. The output power is 1.7 mW, the far field divergence angle is less than 10°, and the side mode suppression ratio is over 30 dB. The output power in the Y direction is 20 times that in the X direction.