Bitapered fiber sensor: Signal analysis

We apply a novel signal analysis of our transmission data to extract a phase shift related to detection of environmental refractive index changes around a bitapered fiber. A high order mode (HOM) and the fundamental mode generate an oscillatory response of the optical fiber sensor as the wavelength is scanned. In our analysis we decompose the signal data into Fourier components and use the dominant oscillation frequency for further analysis. The signal analysis enables improved high-resolution detection.