QCL-Based Cryogen-Free THz Optical Wireless Communication Link
Year: 2024
Authors: Sorgi A., Meucci M., Umair MA., Cappelli F., Toci G., De Natale P., Viti L., Ferrari AC., Vitiello MS., Consolino L., Catani J.
Autors Affiliation: CNR, Ist Nazl Ott, CNR INO, Via N Carrara 1, I-50019 Sesto Fiorentino, FI, Italy; European Lab Non Linear Spectroscopy, LENS, Via N Carrara 1, I-50019 Sesto Fiorentino, FI, Italy; CNR, Scuola Normale Super, NEST, Piazza San Silvestro 12, I-56127 Pisa, Italy; Univ Cambridge, Cambridge Graphene Ctr, Cambridge CB3 0FA, England.
Abstract: The increased demand for high-speed (terabit-per-second) wireless data transmission has driven the shift of the frequency carrier from ubiquitous radio frequency systems toward the 1-5 THz range, triggering a new interest for THz quantum cascade laser (QCL)-based free-space optical (FSO) links. As compared to standard telecom-band FSO links, platforms based on THz frequency sources are inherently robust against Rayleigh scattering. Atmospheric absorption, mainly due to water vapor, limits the achievable link distance range, but at the same time, it shifts channel security on the physical layer. THz QCL-based FSO links are reported with setups requiring cryogenic cooling, seriously limiting their development for mass applications. Here, a cryogen-free, transportable THz FSO communication system is presented relying on a directly modulated 2.83 THz QCL transmitter, hosted in a closed-cycle Stirling cryocooler, and exploiting a room-temperature graphene-based receiver, implementing a binary on-off keying modulation scheme with Manchester encoding. Power-versus-distance measurements and communication tests are performed, and propose a propagation model to extrapolate the performances of the THz link in an optimized configuration. This approach reduces complexity and costs, as compared to the state-of-the-art THz FSO links, and paves the way for the deployment of optical wireless communication systems exploiting the 1-5 THz frequency range.
Journal/Review: LASER & PHOTONICS REVIEWS
More Information: Authors acknowledge funding from Consiglio Nazionale delle Ricerche (Progetti di Ricerca @CNR, TEROCODE and F luoCom projects), Laboratori congiunti ASI-CNR nel settore delle Quantum Technologies (Q-ASINO) funded by ASI and CNR (Accordo Attuativo n.2023-47-HH.0) the European Union Graphene Flagship (core 3), by the ERC Grants (681379) SPRINT, and by the European Union under the Italian National Recovery and Resilience Plan (NRRP) of Next Generation EU, partnership on Telecommunications of the Future (PE00000001 – program RESTART, Structural Project DREAMS, EPSRC Grants EP/K01711X/1, EP/K017144/1, EP/N010345/1, EP/L016087/1, EP/X015742/1, EP/V000055/1, ERC grants Hetero2D, GSYNCOR, GIPT, EU grant Graph-X, European Union – NextGeneration EU, Integrated infrastructure initiative in Photonic and Quantum Sciences – I-PHOQS [IR0000016, ID D2B8D520, CUP B53C22001750006], European Union’s QuantERA II [G.A. n. 101017733] – QATACOMB Project Quantum correlations in terahertz QCL combs (Funding organisations: CNR – Italy).KeyWords: cryogen-free; free-space optical links; FSO communications; GFET; optical wireless communications; quantum cascade lasers (QCL)DOI: 10.1002/lpor.202301082