Unipolar quantum optoelectronics for high speed direct modulation and transmission in 8–14 µm atmospheric window
Hamza Dely, Mahdieh Joharifar, Lauréline Durupt, Armands Ostrovskis, Richard Schatz, Thomas Bonazzi, G. Maisons, Djamal Gacemi, Toms Salgals, Lu Zhang, Sandis Spolītis, Yan‐Ting Sun, Vjačeslavs Bobrovs, Xianbin Yu, I. Sagnes, Konstantinos Pantzas, Angela Vasanelli, Oskars Ozoliņš, Xiaodan Pang, Carlo Sirtori
Abstract
Abstract The large mid-infrared (MIR) spectral region, ranging from 2.5 µm to 25 µm, has remained under-exploited in the electromagnetic spectrum, primarily due to the absence of viable transceiver technologies. Notably, the 8–14 µm long-wave infrared (LWIR) atmospheric transmission window is particularly suitable for free-space optical (FSO) communication, owing to its combination of low atmospheric propagation loss and relatively high resilience to turbulence and other atmospheric disturbances. Here, we demonstrate a direct modulation and direct detection LWIR FSO communication system at 9.1 µm wavelength based on unipolar quantum optoelectronic devices with a unprecedented net bitrate exceeding 55 Gbit s −1 . A directly modulated distributed feedback quantum cascade laser (DFB-QCL) with high modulation efficiency and improved RF-design was used as a transmitter while two high speed detectors utilizing meta-materials to enhance their responsivity are employed as receivers; a quantum cascade detector (QCD) and a quantum-well infrared photodetector (QWIP). We investigate system tradeoffs and constraints, and indicate pathways forward for this technology beyond 100 Gbit s −1 communication.