Visualization 2: Fiber Bragg grating interrogation using wavelength modulated tunable distributed feedback lasers and a fiber-optic Mach–Zehnder interferometer RoyAnirban ChakrabortyArup Lal JhaChandan Kumar 2017 Pulse monitoring using the peak of the 1530.182 nm FBG reflection spectrum while it is attached to a human wrist Originally published in Applied Optics on 20 April 2017 (ao-56-12-3562)