1.2.4 - First-order sapphire fiber Bragg gratings for high temperature sensing

摘要: Sapphire fiber Bragg gratings (SFBG) are presented as a new kind of high temperature sensor that is not sensitive to electromagnetic fields and can be operated in air well inert atmosphere. For inscription first order femtosecond laser pulses with wavelength 400 nm applied. Multiplexing several within one single crystal demonstrated. The were tested for short term up 1,900°C period 28 days at 1,400°C. An adapted signal processing the reflexion spectra highly multimode clad sapphire fibers diameter 100μm allows detecting relative changes better than ±1K. Tubes protect from reactions environment. Applying bare detect Hz speed. Strain designs strain measurements based on SFBG applications 600°C tested, too. sensitivity sensors ∆l / l = 10 (10μstrain). Overall, grating inside provide base precise high-temperature key advantages such multiplexing, large bandwidth insensitivity fields.