Sensor láser de fibra óptica con una cavidad de 8.6 km formada por dos rejillas de Bragg usadas como espejos.

Abstract

We report the operation of a fiber laser sensor made by an Erbium Doped Fiber pumped at $980nm$, an $8.67km$ passive fiber and two fiber Bragg gratings placed at the ends of the laser cavity. Under normal conditions, the Bragg gratings have different reflection wavelengths and laser emission is not generated. The two Bragg gratings can be placed at the same reflection wavelength when the Bragg grating with the lowest reflective wavelength is strained which can be used as a sensor element. The laser generation thus shows that the Bragg grating is under strain. Furthermore, our configuration gives us the possibility for knowing the distance between two Bragg gratings when the laser beating frequency is measured. A measurement precision better than $25m$ in $8.67Km$ is shown to be feasible.