Copper oxide coated D-shaped optical fibers for the development of LMR refractometers

Lossy mode resonance (LMR) based refractometers obtained by means of copper oxide thin-films fabricated onto side-polished (D-shaped) are presented in this work. The high refractive index of copper oxide combined with the propagation mode isolation capabilities of D-shaped fibers allows for the observation of narrow (30 nm) and high sensitive (10,336 nm per refractive index unit) LMRs, which could enable to improve the performance of LMR-based refractometers as well as provide an alternative label-free sensing platform for LMR-based sensors.The authors would like to acknowledge the support from the Spanish Agencia Estatal de Investigación (AEI) (PID2019-106231RB-I00) and the Public University of Navarra (PJUPNA26). A. O. C. would also like to thank the Spanish Ministry of Universities (FPU15/05663)