Erbium-doped fiber ring cavity assisted by an FBG and PS-FBG reflector for refractive-index measurements - INVITEDRosa Ana Perez-Herrera, Hector Diaz, Liliana Soares, Susana Novais, Manuel Lopez-Amo, Susana Silva and Orlando FrazãoEPJ Web Conf., 287 (2023) 09012DOI: https://doi.org/10.1051/epjconf/202328709012