Intensity-modulated refractive index sensor based on optical fiber with slanted end

In this work, the design, construction, and testing of an intensity-modulated refractive index (RI) sensor based on fiber optics which distal end is mechanically polished at 45 degrees, forming a slanted end, is presented. A model that accounts for the formation of an optical reflection spectrum registered in an Optical Spectrum Analyzer (OSA), whose intensity is modulated by the RI of the medium in which the fiber end is in contact with, is proposed and simulated. This structure proves the feasibility of this sensor for RI measurements of saline solutions, exhibiting an intensity-modulated response with sensitivity of -136 dBm/RIU. This cost-effective device is simple to construct and easy to implement, which makes it very promising for refractive index sensing in chemical and biomedical applications.