Long-Wave Infrared Discrete Multitone Free-Space Transmission Using a 9.15-μm Quantum Cascade Laser
Mengyao Han, Mahdieh Joharifar, Muguang Wang, Yuchuan Fan, G. Maisons, Johan Abautret, Yan‐Ting Sun, R. Teissier, Lu Zhang, Vjačeslavs Bobrovs, Xianbin Yu, Richard Schatz, Sergei Popov, Oskars Ozoliņš, Xiaodan Pang
Abstract
A free-space optical (FSO) transmission system is experimentally demonstrated in the long-wave infrared (LWIR, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.15~\mu \text{m}$ </tex-math></inline-formula> ) using a directly modulated quantum cascade laser (DM-QCL) and a commercial mercury-cadmium-telluride infrared photovoltaic detector. At room temperature, the DM-QCL is current-modulated by discrete multitone signals pre-processed with bit-/power-loading. Up to 5.1 Gbit/s data rate is achieved with bit error rate performance below the 6.25% overhead hard-decision forward error correction limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5\times 10^{-3}$ </tex-math></inline-formula> , enabled by a frequency domain equalizer. The stability study of the FSO system is also performed at multiple temperature values. This study can provide a valuable reference for future terrestrial and space communications.