Low Threshold Current Single-Fundamental-Mode Photonic Crystal VCSELs

An optimization of oxide aperture diameter to match the light emission aperture (the central defect region) in the photonic crystal vertical-cavity surface-emitting laser (PhC-VCSEL) is presented in order to obtain low threshold current and high single-fundamental-mode output of the device. A 3-D finite-difference time-domain method has been applied to simulate the mode field distribution and quality factors (Q factors) of fundamental and high order transverse modes which correspond to the mode loss of the PhC-VCSEL cavity. Single-fundamental-mode operation of PhC-VCSEL with 1.7-mW output power and low threshold current of 0.7-mA is demonstrated after oxide aperture optimization.