Erbium emission from porous silicon one-dimensional photonic band gap structures

Abstract

We report tunable, narrow, directional, and enhanced erbium emission from one-dimensional photonic band gap structures. The structures are prepared by anodic etching of crystalline silicon and consist of two highly reflecting porous silicon Bragg reflectors sandwiching an active layer. The cavities are doped by cathodic electromigration of the erbium ions into the porous silicon matrix, followed by high temperature oxidation. By controlling the oxidation temperature of the structure, the position of the erbium emission near 1.5 μm is tuned to regions where the natural erbium spectrum is very weak. The erbium emission from the cavity is narrowed to a full width at half maximum of 12 nm with a quality factor Q of 130, highly directional with a 20° emission cone around the normal axis, and enhanced by more than one order of magnitude.