Adiabatic design of micropillar cavities for 1.55-µm quantum-dot single-photon sources

Abstract

Strongly required by silica-fiber-based quantum information processing, 1.55-µm micropillar cavities must be well created to serve as promising quantum-dot (QD) single photon sources (SPSs). Adiabatic design is proved an effective way. With inserted tapered (thickness decreased towards the center) Distributed Bragg reflectors (DBRs), an InGaAsP/InP micropillar cavity becomes more likely to be producible and useful at 1.55 μm. A SiSiO 2 -InP hybrid micropillar cavity, which enables weakly coupling InAs/InP QDs, can even well satisfy strong coupling at smaller diameter by incorporating adiabatically tapered Si/SiO2 DBRs. Not only taper structure, other adiabatic designs, e.g., both DBR layers getting thicker, one thicker one thinner and etc., also improve the quality, reduce the diameter and degrade the fabrication difficulty of Si/SiO 2 -InP hybrid micropillar cavities. The problem of thin epitaxial semiconductor layer can be greatly resolved by inserting adiabatic InGaAsP/InP DBRs. To get a monolithically producible cavity, adiabatically tapered DBRs are inserted into an InGaAsP/InP-air-aperture micropillar cavity. It brings about high quality satisfying both weak and strongly coupling. The proposed cavities with adiabatic designs are prospective candidates for 1.55-μm QD-SPSs.