Low-coherence sensors with nanolayers for biomedical sensing

In this paper, we describe the fiber optic low-coherence sensors using thin film. We investigated their metrological parameters. Presented sensors were made with the use of standard telecommunication single mode optical fiber (SMF- 28). Different materials were applied to obtain thick layers, such as boron doped diamond, silver and gold. The thickness of layers used in the experiments ranged from 100 nm to 300 nm. Measurements were performed with broadband source operating at central wavelength 1300 nm. The measurement signal was acquired by an optical spectrum analyzer. Measured signal was analyzed in the spectrum domain. Any change of the phase difference between interfering beams reflected from the sensor head depends on measurand occurred in the spectrum of the measurement signal. We obtain the visibility value of the measured signal equal to 0.97.