Figure 4
From: Ultra-fast polymer optical fibre Bragg grating inscription for medical devices
FBG waveforms generated from heartbeat monitoring. (a) Reflection spectrum of the silica FBG used in the experiment. (b) Reflection spectrum of the 7 ms polymer FBG (stabilized for a few months after UV exposure) used in the experiment. (c) Filtered reflection peak wavelength shift of the silica (top) and polymer FBG (bottom).
