Tilted FBG Sensing in Microfluidic Chips Through Spectral Discretization

The transmission or reflection spectrum of a tilted fiber Bragg grating (TFBG) consists of a dense comb of mode resonances that are sensitive to liquids or layers that surround the grating. Thus, TFBGs represent a good alternative to develop a variety of physical and bio-chemical sensors [1]–[3]. However, their interrogation typically entails polarization controllers and expensive instruments with high spectral resolution over a broad wavelength range (~80 nm). These requirements increase the overall cost and complexity of sensors based on TFBGs. To overcome such drawbacks, new sensor architectures and signal processing have been proposed [4], [5].