SLM fiber laser stabilized at high temperature

Abstract

In this letter, an annealing process of UV-written fiber Bragg gratings (FBGs) has been employed to achieve FBGs with narrower reflection spectra to be employed in fiber lasers. These FBGs have been used to design distributed Bragg relfector (DBR) laser sensors working on the single longitudinal mode (SLM) regime even at high temperatures. A fiber laser sensor working on multimode regime has been written into commercial Er-doped fiber before annealing its mirror FBGs, removing the unstable UV-induced modulation part and narrowing the FBGs' combined response. This process obtains a DBR fiber laser sensor working on SLM regime at high temperatures (T = 500°C), and also exhibiting a remarkably good linearity and stability. The achieved results confirm the empirically adjusted aging model and prove its usefulness to design high precision devices able to work at high temperatures.