Abstract
We demonstrate the fabrication of multi-layer sapphire fiber Bragg gratings (SFBGs) using a femtosecond laser line-by-line scanning technique. This multi-layer grating structure enlarges the index modulation area and can effectively increase the reflectivity of SFBGs. The spectral characteristics of multi-layer SFBGs with different layer quantities and spacings were studied. A double-layer SFBG with a layer spacing of 5μm exhibits a reflectivity of 34.1%, which is much higher than that of a single-layer SFBG (i.e., ∼6.3%). Moreover, the higher-order modes of multi-layer SFBG could be suppressed by offset coupling, leading to a reduced SFBG bandwidth (full width at half-maximum [FWHM]) of 1.32nm. In addition, the high-temperature response of the multi-layer, offset-coupled SFBGs was also studied. The SFBG can withstand a high temperature of 1612°C and exhibits a sensitivity of 45.2 pm/°C at high temperatures. Such multi-layer, offset-coupled SFBGs could be developed for high-temperature sensing in metallurgical, chemical, and aviation industries.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
