High-Brightness Low-Divergence Tapered Lasers with a Narrow Taper Angle**Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0402203 and 2016YFA0301102, and the National Natural Science Foundation of China under Grant Nos 61535013 and 91850206.

Abstract

High-brightness tapered lasers with photonic crystal structures are designed and fabricated. A narrow taper angle is designed for the tapered section. The device delivers an output power of 3.3 W and a maximum wall-plug efficiency of 43%. The vertical beam divergence is around 11° at different currents. Nearly diffraction-limited beam qualities for the vertical and lateral directions are obtained. The lateral beam quality factor M2 is below 2.5 and the vertical M2 value is around 1.5 across the whole operating current range. The maximum brightness is 85 MW·cm−2sr−1. When the current is above 3.3 A, the brightness is still above 80 MW·cm−2sr−1.