Submicron size all-semiconductor vertical cavities with high Q

Abstract

The miniaturization of lasers promises on-chip optical communications and data processing speeds that are beyond the capability of electronics and today's high-speed lasers. Lasers with low-power consumption are one of the most important parts in creating a photonics integrated architecture. This requirement was the motivating force behind the development of small laser and nanolasers. Here, we propose a new method that could be utilized to fabricate such a laser. Oxide-VCSELs require strict control of the oxidation process with significantly reduced reliability for small size, and micropillars have degraded Q with fabrication artifacts for submicron diameter pillars. We propose to use a phase-shifting current-blocking (PSCB) layer serving dual function for a nanocavity device (Fig. 1a) providing both optical- and electrical-confinement via lithographically defined and selectively-biased buried structures. Phase-shifting leads to optical-confinement tuning by layer thickness control and current-blocking provides electrical-confinement. By modifying the dimensions of these layers, the confinement can be tuned by lithographic means. We studied the electromagnetic wave propagation and analyzed the quality factor (Q) of these cavities based on 3D finite difference time domain (FDTD) calculations.