| PhD Seminar

Name of the Speaker: Ms. Neethu Sasikumar (EE18D043)
Guide: Prof. Balaji Srinivasan
Venue: ESB-244 (Seminar Hall)
Date/Time: 15th January 2025 (Wednesday), 2:00 PM
Title: Investigation of Performance Limits of Phase-Optical Time Domain Reflectometry based Distributed Acoustic Sensors

Abstract :

Distributed Acoustic Sensing (DAS) based on phase-sensitive Optical Time Domain Reflectometry (ɸ-OTDR) has emerged as a transformative technology for real-time monitoring across diverse applications, including structural health monitoring, oil and gas pipeline surveillance, security, and geophysical studies. Optical fiber-based DAS systems provide significant advantages, such as leveraging existing commercial fiber networks, enabling large sensing ranges, and delivering distributed measurements with high spatial resolution (SR). As the demand for higher sensitivity, improved spatial resolution, and longer sensing distances grows, optimizing phase-OTDR system performance has become a critical research focus.

This work investigates the performance limits and optimization strategies of various ɸ-OTDR schemes. A comprehensive numerical model and a corresponding simulation framework are employed to evaluate key factors affecting the DAS performance measured in terms of sensitivity, signal-to-noise ratio (SNR), and dynamic range. The study also investigates the effects of system noise and non-linearities, offering critical insights for developing effective optimization strategies.

Experimental results demonstrate high dynamic range sensing over distances up to 40 km with a spatial resolution of 10 m, highlighting the inherent trade-offs and practical constraints of phase-OTDR systems. To further enhance performance, advanced techniques such as Time Expanded (TE) ɸ-OTDR are explored, demonstrating their potential to significantly improve both SNR and spatial resolution. By integrating theoretical foundations with simulation and experimental validation, this work establishes a comprehensive framework for designing high-performance DAS systems capable of meeting user specific applications.