Bravo Acha, MikelBaptista, José ManuelSantos, José LuísLópez-Amo Sáinz, ManuelFrazão, Orlando2020-01-132020-01-1320111539-479410.1364/OL.36.004059https://academica-e.unavarra.es/handle/2454/36021A 253 km ultra long remote displacement sensor system based on a fiber loop mirror interrogated by a commercial OTDR is proposed and experimentally demonstrated. The use of a fiber loop mirror increases the signal to noise ratio allowing the system to interrogate sensors placed 253 km away from the monitoring system without using any optical amplification. The displacement sensor was based on a long period grating spliced inside of the loop mirror, which modifies the mirror reflectivity accordingly to the applied displacement.5 p.application/pdfeng© 2011 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited.Ultralong remote sensorsFiber loop mirrorsOptical time-domain reflectometersinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess