Dynamic Dispersive Spectrometer using a Fiber Bragg Grating for High Pressure Measurements

Yohan Barbarin (1) , A. Lefrancois (1) , F. Sinatti (1) , A. Bey (1) , M. Balbarie (1) , A. Osmont (1) , J. Luc (1)

1 DAM/GRAMAT - GRAMAT

A new high resolution dispersive spectrometer has been developed to measure high pressure shock profiles every 10 ns using long Fiber Bragg Gratings. The performances are compared with a dynamic AWG-based spectrometer. Two small diameter fibers allow inserting in parallel two 50-mm long gratings into the target. The use of slightly chirped gratings provides the localization of the shock-wave along them. Placed along the target axis, a gratings reflected spectrum is "blue shifted". The FBG's central wavelength are 1605 nm to cover a pressure range of 0-8 GPa. The new spectrometer is based on a femtosecond laser source, a long dispersive fiber and a fast acquisition system with an electrical bandwidth above 30 GHz. The experimental setup was a symmetric impact with 6061T6 aluminum, performed with a 110-mm in diameter single-stage gas gun. An impact velocity of 314 m/s is obtained and generated a sustained level of 2.1 GPa during few microseconds. A resulted Bragg shift of (16 ± 1) nm is measured. The dispersive spectrometer offers much greater resolution than the AWG one which is favorable to retrieve more easily a pressure profile.

Keywords: Fiber Bragg Grating; Shock; Spectrometer; High Energy Material; Femtosecond Laser

Domains: Physics [physics]; Physics [physics]; Instrumentation and Detectors [physics.ins-det]; Engineering Sciences [physics]; Optics / Photonic

Yohan Barbarin, A. Lefrancois, F. Sinatti, A. Bey, M. Balbarie, et al.. Dynamic Dispersive Spectrometer using a Fiber Bragg Grating for High Pressure Measurements. 2016 IEEE SENSORS, Oct 2016, Orlando, United States. pp.1-3, ⟨10.1109/ICSENS.2016.7808769⟩. ⟨cea-02549096⟩