Dual-wavelength fiber lasers have become an attractive candidate for the last few years in the area of optical imaging, optical communication, optical sensing, microwave, and terahertz signal generation. It offers small size, inexpensive, and simple fabrication along with high scalability to the existing state-of-the-art microwave-photonics networks. In this paper, we demonstrate experimentally a switchable dual-wavelength fiber laser for the generation of the radio frequency signals in the millimeter band (up to -110 GHz). The fiber laser is based on a nonlinear polarization rotation ring-cavity consisting of erbium-doped fiber and a high birefringence fiber of 1 m and 10 m length, respectively. By proper adjustment of the laser cavity birefringence via controlling the polarization controllers in the laser cavity, the laser output spectrum can be tuned to attain a dual-wavelength spacing in the range of 0.1 nm–0.89 nm to generate flexible and stable millimeter waves with an adjustable span of 12.3 GHz to 110 GHz. The obtained results reveal the potential of the proposed laser to be used to realize different microwave-photonic systems/networks, for instance, 5G networks, internet of things, surveillance and monitoring, remote sensing, self-driving vehicles, photonics-based radar systems, meteorology and so on.
Bibliographical note© 2020, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Funding: This work is carried out in Aston Institute of Photonic Technologies, School of Engineering and Applied Sciences, Aston University, Birmingham, UK and is supported by European Union sponsored H2020-MSCA-IF-EF-ST project no: 840267.