Influence of confined layer on characteristics of current density and carrier diffusion in VCSEL

Abstract

Injected-current density and carrier distribution are crucially important factors in Vertical-cavity surface-emitting laser (VCSEL) characteristics, affecting the laser emission wavelength, distribution of transverse-mode, threshold voltage, available output power and operating laser lifetime. Using a method of finding self-consistent solution for the carrier-diffusion and Poisson's equations, of calculating beginning from electrode voltage and of taking into account the whole structure of distributed Bragg reflectors (DBR), we have studied the two-dimensional current density and carrier distribution characteristics of VCSEL. The calculated results show that the injected-current density and carrier distribution determined by the confined-layer depth in VCSEL. The deeper confined-layer in VCSEL is, the more notable current density and carrier distribution are limited in the active region. So the strong confinement benefits to concentrate the current density in the active region to a higher level, at the same time ofthe reduction ofthe threshold.