Robust single-mode emission from mid-IR photonic crystal interband cascade lasers

Abstract

ABSTRACT Electrically-pumped photonic-crystal distributed-feedback lasers with interband-cascade active regions operating in single spectral mode at 3.3 P m are demonstrated. At 78 K, a stripe of width 400 P m emits up to 67 mW of cw power into a single spectral mode with side-mode suppression ratio | 27 dB. The full-width at half-maximum of the far-field divergence angle is | 0.5 o , which combined with the near-field profile yields an effective M 2 of 1.7-2.0. Keywords: diode laser, interband cascade laser, quantum well, mid-infrared, photonic-crystal distributed-feedback laser. 1. INTRODUCTION In a photonic-crystal distributed-feedback (PCDFB) laser, three distinct (non-collinear) in-plane diffraction mechanisms 1-3 work together to defeat filamentation provided that the grating strength and gain stripewidth satisfy certain appropriate conditions. This makes the PCDFB capa ble of maintaining strong optical coherence over very large lateral areas. The first experimental demonstrations employed pulsed optical pumping of midwave-infrared (mid-IR) type-II antimonide structures.