Continuous wave quantum cascade lasers with 5.6 W output power at room temperature and 41% wall-plug efficiency in cryogenic operation

F Wang,Q Y Lu,M Razeghi,S Slivken,D H Wu

doi:10.1063/5.0003318

Abstract

In this paper, we report a post-polishing technique to achieve nearly complete surface planarization for the buried ridge regrowth processing of quantum cascade lasers. The planarized device geometry improves the thermal conduction and reliability and, most importantly, enhances the power and efficiency in continuous wave operation. With this technique, we demonstrate a high continuous wave wall-plug efficiency of an InP-based quantum cascade laser reaching ∼41% with an output power of ∼12 W from a single facet operating at liquid nitrogen temperature. At room temperature, the continuous wave output power exceeds the previous record, reaching ∼5.6 W.

Highlights

Continuous wave quantum cascade lasers with 5.6 W output power at room temperature and 41% wall-plug efficiency in cryogenic operation
The quantum cascade laser (QCL) is a unipolar quantum device fully based on a semiconductor technology platform
It is of great importance to optimize the wall-plug efficiency (WPE) as it can, on the one hand, maximize the useful energy of a QCL and, on the other hand, reduce the heat produced within the laser system

Summary

Introduction

Continuous wave quantum cascade lasers with 5.6 W output power at room temperature and 41% wall-plug efficiency in cryogenic operation. We redesign the buried ridge regrowth process and introduce a post-polishing technique to achieve better surface planarization and improve the device reliability and performance.

Results

Conclusion