High-resolution fiber optic sensing based on self-mode-locked optoelectronic oscillator

High-precision fiber-optic sensing is essential for advanced optical metrology and structural health monitoring; however, conventional techniques are often limited by insufficient sensitivity, demodulation errors, and system instability. To address these challenges, in this work, we propose a high-resolution fiber-optic sensing scheme based on a self-mode-locked optoelectronic oscillator (OEO) incorporating an envelope-free virtual Vernier effect. A microwave frequency comb (MFC) generated by the OEO serves as a highly stable and low-noise sensing carrier, while the virtual Vernier mechanism enables precise frequency demodulation without the need for envelope extraction. This design effectively suppresses noise accumulation and minimizes demodulation errors, leading to substantial improvements in sensing precision and repeatability. Experimental results demonstrate a clear performance enhancement over conventional OEO-based sensing schemes. Furthermore, the envelope-free configuration simplifies the system architecture and enhances robustness against environmental perturbations. Overall, this work presents a compact and effective microwave photonic sensing strategy, offering a scalable route toward high-performance and stable fiber-optic sensing for practical engineering applications.