Fiber laser strain sensor device

We present a Fiber Laser Strain Sensor (FLSS) with spectral resolution equal to or better than 250 pe/(Hz)1/2 at very low frequencies, from 100 mHz to some hundreds Hz. The strain affects the fiber laser emission wavelength, and an imbalanced Mach-Zender Interferometer (MZI) converts wavelength variations into phase-amplitude variations. The answer of the sensor in the time domain has been also analyzed, by applying sinusoidal strain bursts, and nano-strain resolution has been demonstrated.