1.3 µm Distributed Feedback Laser with Half-Etching Mesa and High-Density Quantum Dots

Abstract

We propose a quantum dot laser with a new distributed feedback (DFB) structure, namely, a half-etching mesa (HEM) DFB laser that employs a vertical grating structure and requires no regrowth process. The features of the HEM structure are a low coupling coefficient and a low threshold current achieved by suppressing the large scattering loss in the quantum dots (QDs) active layer. This structure is realized by etching vertical gratings only as far as the center of the active layer. We demonstrated fundamental mode control for a 1.3 µm emission with a low coupling coefficient of 22 cm-1 and a threshold current of 35 mA by using high-density and high-uniformity QDs.