Distributed SOP tracking fault detection technique for MeerKAT radio telescope array sub-metre single mode fibre link health monitoring

摘要

Deployed short-run receptor fibre network (RFN) in the MeerKAT radio telescope array require frequent health assessment due to their harsh environmental exposures. The inherent launch and event dead-zone of optical time-domain reflectometry (OTDR) technique limits its application in the MeerKAT radio telescope RFN submetre fibre links. This work experimentally demonstrates the first distributed polarization-based precise fault detection technique based on state-of-polarization (SOP) change tracking, for health monitoring of sub-metre fibre links and passive/active optical/photonic components. A beat frequency signature due to interference of the local oscillator with Rayleigh backscattered and Fresnel reflected optical signal is exploited to monitor Birefringence evolution over a 0.35 m MeerKAT digitizer fibre loom. Utilizing the ultra-sensitive inherent SOP change functionality due to mode coupling between fast and slow eigenmodes, an SOP change tracking technique is developed offline with 0.05 degrees SOP angle change detection precision at 125 mu m spatial resolution. Fault location performance of the developed SOP change tracking technique is then compared to classical optical frequency-domain reflectometry (OFDR) technique over a 0.28 m SMF fibre link. The developed SOP change tracking technique is adopted for precise fault location along a 0.35 m MeerKAT digitizer fibre loom due to its high sensitivity. This work offers a precisely accurate, stable and reproducible approach for location of propagation defect detection in sub-metre single mode optical fibre links.