Effect of TiO2 coating on neutron response of UV-written B-Ge co-doped optical fiber long-period gratings

This contribution presents the response to neutron irradiation of Long Period Gratings (LPGs) inscribed in a B/Ge codoped optical fiber by means of an excimer laser. The effect of a nanoscale titanium dioxide (TiO₂) coating is discussed. The experiment was conducted in the TRIGA MARK II research reactor of the Jožef Stefan Institute in Ljubljana, where the optical fiber devices were subjected to a total accumulated fluence of approximately 3.4×10¹⁵ n/cm². The impact of neutron irradiation on the spectral responses of the LPGs under analysis was investigated in terms of both radiationinduced shifts and changes in visibility. The presented results highlight the potential of nanoscale layers to modulate the sensitivity of LPG-based devices to radiation, thus providing a pathway for tailoring their response in specific applications of radiation dosimetry and in neutron rich environments.