Fiber laser strain sensor device

We present a fiber laser strain sensor (FLSS) with noise-equivalent sensitivity equal to or better than 80?p?rms?(Hz)?1/2 at very low frequencies, from 100?mHz to several hundreds of hertz. The strain affects the fiber laser emission wavelength, and an imbalanced Mach?Zender interferometer (MZI) converts wavelength variations into phase-amplitude variations. The sensor has been also tested in the time domain by applying sinusoidal strain bursts: the device also shows a good signal-to-noise ratio at the lowest burst frequencies.