Abstract

A roadmap for future wireless communications is expected to exploit all transmission-suitable spectrum bands, from the microwave to the optical frequencies, to support orders of magnitude faster data transfer with much lower latency than the deployed solutions nowadays. The currently under-exploited mid-infrared (mid-IR) spectrum is an essential building block for such an envisioned all-spectra wireless communication paradigm. Free-space optical (FSO) communications in the mid-IR region have recently attracted great interest due to their intrinsic merits of low propagation loss and high tolerance of atmospheric perturbations. Future development of viable mid-IR FSO transceivers requires a semiconductor source to fulfill the high bandwidth, low energy consumption, and small footprint requirements. In this context, quantum cascade laser (QCL) appears as a promisingtechnological choice. In this work, we present an experimental demonstration of a mid-IR FSO link enabled by a 4.65-μm directly modulated (DM) QCL operating at room temperature. We achieve a transmission data rate of up to 6 Gbps over a 0.5-m link distance. This achievement is enabled by system-level characterization and optimization of transmitter and receiver power level and frequency response and assisted with advanced modulation and digital signal processing (DSP) techniques. This work pushes the QCL-based FSO technology one step closer to practical terrestrial applications, such as the fixed wireless access and the wireless mobile backhaul. Such a QCL-based solution offers a promising way towards the futuristic all-spectra wireless communication paradigm by potentially supporting the whole spectrum from the MIR to the terahertz (THz).

Gigabit free-space multi-level signal transmission with a mid-infrared quantum cascade laser operating at room temperature

Xiaodan Pang, Oskars Ozolins, Richard Schatz, Joakim Storck, Aleksejs Udalcovs, Jaime Rodrigo Navarro, Aditya Kakkar, Gregory Maisons, Mathieu Carras, Gunnar Jacobsen, Sergei Popov, and Sebastian Lourdudoss
Opt. Lett. 42(18) 3646-3649 (2017)

Characterization of noise regimes in mid-IR free-space optical communication based on quantum cascade lasers

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Opt. Express 30(25) 44640-44656 (2022)

10 Gbps DPSK transmission over free-space link in the mid-infrared

Yulong Su, Wei Wang, Xiaohong Hu, Hui Hu, Xinning Huang, Yishan Wang, Jinhai Si, Xiaoping Xie, Biao Han, Huan Feng, Qiang Hao, Guoshen Zhu, Tao Duan, and Wei Zhao
Opt. Express 26(26) 34515-34528 (2018)

Frequency noise of free-running 4.6 μm distributed feedback quantum cascade lasers near room temperature

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150 Gbps multi-wavelength FSO transmission with 25-GHz ITU-T grid in the mid-infrared region

Yulong Su, Jiacheng Meng, Tingting Wei, Zhuang Xie, Shuaiwei Jia, Wenlong Tian, Jiangfeng Zhu, and Wei Wang
Opt. Express 31(9) 15156-15169 (2023)