Deeply etched waveguide structures for quantum cascade lasers

A high density plasma process was developed for reactive ion etching (RIE) of GaAs/AlGaAs based devices which can be applied for the processing of advanced resonator designs. We present diffractive resonators fabricated using inductively coupled plasma (ICP) RIE with SiCl4 chemistry. A sidewall protection is formed during the process, which allows for steep vertical and smooth profiles. The technology therefore improves the fabrication of sophisticated QCL cavities and results of the first laterally coupled distributed feedback (DFB) QCLs are presented together with our progress made in etching photonic crystal QCLs. (c) 2006 Elsevier B.V. All rights reserved.