Ghost modes in Terahertz Quantum Cascade Laser waveguides

Abstract

Degeneration of the lasing mode in a Terahertz Quantum Cascade Laser due to interaction with parasitic ghost modes is demonstrated here through rigorous numerical analysis. We show that such interactions can adversely affect the performance of a QCL by causing abrupt rises in lasing threshold. We also show that such affects can be avoided by altering the width of the metal cladding layer.