Metal Organic Chemical Vapor Deposition-Grown High-Power Photonic-Crystal Surface-Emitting Lasers toward L Band

Abstract

High-power lasers emitting in the L band wavelength range are highly desirable for various applications, including light detection and ranging, industrial applications, military applications, gas sensing, and optical communication. In this study, we present our research on InP-based photonic-crystal surface-emitting lasers (PCSELs) designed to achieve high-power emission in the L band while maintaining a compact device size. To enable vertical laser emission, we incorporated embedded air voids within a 2D photonic crystal (PC) structure by epitaxial overgrowth. The PC was carefully designed to facilitate lasing at the PC band edge of the Γ point. While the fabrication of InP-based distributed feedback edge-emitting lasers with epitaxial regrowth and p-type cladding layers has reached commercial maturity, the process of retaining air holes presented unique challenges in our work. We conducted an investigation into the regrowth processes, aiming to preserve the air voids while achieving an atomically flat p-type surface for our flip-chip device structure. The flat surface is crucial to minimize scattering losses and ensure optimal reflectivity of the p-side metal, resulting in higher output efficiency. The PCSELs demonstrated in our study achieved an optical power of more than 150 mW in the L band, utilizing an aperture of only 280 μm in diameter. We anticipate that with further optimization, we can achieve even higher power and efficiency levels.