Efficient Compensation Methods for SOP Drift in Hybrid Fiber-FSO Link-Based QKD Systems
Year: 2026
Type: conference-paper
Abstract: Quantum key distribution (QKD) uses fundamental principles of quantum mechanics to enable information-theoretic secure communication, emerging as a key element for future-proof secure communication infrastructures. This contrasts with classical cryptographic systems, whose security relies on computational assumptions and is therefore vulnerable to advances in algorithms and computing power. From a practical perspective, QKD systems greatly benefit from the use of already deployed fiber-optic networks, which facilitate scalable and cost-effective implementation. However, optical fibers are inherently affected by intrinsic and extrinsic birefringence, leading to random and timevarying changes in the state of polarization (SOP) of the transmitted qubits. These polarization fluctuations can severely degrade system performance, making effective SOP tracking and compensation techniques essential. This paper presents our recent investigations on SOP drift compensation in fiber-link-based QKD systems, comparing different approaches with the aim of identifying solutions that combine simplicity, robustness, and high efficiency. Additionally, we discuss applying these algorithms in the context of beyond fiber-optic quantum channels, specifically free-space optical (FSO) links and hybrid links combining fiber and free-space segments.
Institution: Instituto de Telecomunicações
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7215111978