Dejneka, ZachHoma, DanielBuontempo, JoshuaCrawford, GideonMartin, EileenTheis, LoganWang, AnboPickrell, Gary R.2024-04-292024-04-292024-04-10Dejneka, Z.; Homa, D.; Buontempo, J.; Crawford, G.; Martin, E.; Theis, L.; Wang, A.; Pickrell, G. Magnetic Field Sensing via Acoustic Sensing Fiber with Metglas® 2605SC Cladding Wires. Photonics 2024, 11, 348.https://hdl.handle.net/10919/118695Magnetic field sensing has the potential to become necessary as a critical tool for long-term subsurface geophysical monitoring. The success of distributed fiber optic sensing for geophysical characterization provides a template for the development of next generation downhole magnetic sensors. In this study, Sentek Instrument’s <i>picoDAS</i> is coupled with a multi-material single mode optical fiber with Metglas<sup>®</sup> 2605SC cladding wire inclusions for magnetic field detection. The response of acoustic sensing fibers with one and two Metglas<sup>®</sup> 2605SC cladding wires was evaluated upon exposure to lateral AC magnetic fields. An improved response was demonstrated for a sensing fiber with in-cladding wire following thermal magnetic annealing (~400 °C) under a constant static transverse magnetic field (~200 μT). A minimal detectable magnetic field of ~500 nT was confirmed for a sensing fiber with two 10 μm cladding wires. The successful demonstration of a magnetic field sensing fiber with Metglas<sup>®</sup> cladding wires fabricated via traditional draw processes sets the stage for distributed measurements and joint inversion as a compliment to distributed fiber optic acoustic sensors.application/pdfenCreative Commons Attribution 4.0 InternationalMagnetic Field Sensing via Acoustic Sensing Fiber with Metglas® 2605SC Cladding WiresArticle - Refereed2024-04-26Photonicshttps://doi.org/10.3390/photonics11040348