25-Gb/s Direct Modulation of Implant Confined Holey Vertical-Cavity Surface-Emitting Lasers

A 25-Gb/s direct modulation of an 850-nm implant-confined holey vertical-cavity surface-emitting laser (VCSEL) is demonstrated with a low operation current density of 7.4 KA/cm
²
. The high-speed performance arises from cavity designs that are achieved using standard fabrication and epitaxial materials. The etched holey structure is incorporated into the top mirror of the VCSEL to tailor the size of the optical cavity independent from that of the electrical current aperture, enabling us to achieve high-speed modulation and low operation current density simultaneously.