Abstract-Multi-Terahertz sideband generation on an optical telecom carrier with a Quantum Cascade Laser

Sarah Houver, Armand Lebreton, Alireza Mottaghizadeh, Maria Amanti, Carlo Sirtori, Gregoire Beaudoin, Isabelle Sagnes, Olivier Parillaud, Raffaele Colombelli, Juliette Mangeney, Robson Ferreira, Jérôme Tignon, and Sukhdeep Dhillon

http://pubs.acs.org/doi/abs/10.1021/acsphotonics.7b01124

Quantum Cascade Lasers (QCLs) are the principal semiconductor light sources for the mid-infrared (MIR) and terahertz (THz) spectral regions. However, up-converting their emission to the technologically mature telecom spectral region (1.3µm to 1.6µm) remains an important goal for applications. This would permit new QCL functionalities to be realized, such as stabilization and injection locking of the QCL emission to precise and low cost telecom frequency combs for spectroscopy. In this work, we demonstrate the up-conversion of the QCL emission to the telecom band at room temperature, using the QCLs’ inherent resonant optical nonlinearities. This is based on the generation of multi-THz sidebands on a telecom carrier, where a low power telecom beam at 1.55 µm is injected into the cavity of an InP-based MIR QCL (9 µm, 33 THz), giving rise to the nonlinear sum frequency at 1.3 µm. The results are supported by a theoretical model that highlights the giant enhancement of the nonlinear interaction through the resonant telecom excitation and the reduced role of phase matching. As well as potentially bringing important spectroscopic capabilities to QCLs, this compact and low power all-optical connection between the low-loss transmission windows of 1.3 µm and 1.55 µm would potentially permit QCLs to be applied as ultrafast wavelength shifters in fiber telecommunication networks.