Polarization control is essential for maintaining the performance and stability of fiber-optic sensing and optical communication systems, since the state of polarization in fiber links is highly susceptible to birefringence variation and environmental perturbations. This review summarizes recent advances in polarization control for fiber links from the perspectives of polarization evolution mechanisms, target performance parameters, application-specific requirements, and representative technical implementations. Passive polarization-control schemes are first discussed, with emphasis on loop-based architectures, all-polarization-maintaining configurations, and integrated passive approaches. Active polarization-control techniques are then reviewed, including manual fiber polarization controllers, Faraday-effect-based devices, lithium-niobate electro-optic controllers, and other emerging platforms such as silicon photonics and liquid-crystal-integrated devices. Their operating principles, structural characteristics, and key performance metrics are compared. Recent progress shows that the field is evolving from static and discrete schemes toward high-speed, closed-loop, and highly integrated architectures. Despite these advances, achieving a balanced combination of low loss, high extinction ratio, ultrafast response, low power consumption, compact footprint, and long-term stability remains a major challenge for practical deployment. Received: 31 March 2026 | Revised: 3 June 2026 | Accepted: 17 July 2026 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study. Author Contribution Statement Zhihang Zhang: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Supervision, Project administration, Funding acquisition. Yujie Zheng: Software, Writing – review & editing. Xiao Wu: Project administration. Jianhua Yang: Investigation. Heming Wei : Resources, Supervision. Long Ma: Data curation. Xiaohu Liu: Writing – original draft. Dapeng Han: Formal analysis, Funding acquisition. L ijun Miao: Investigation, Visualization. Dengwei Zhang: Software, Validation, Supervision, Project administration, Funding acquisition.