Comparison of Broadband Loss in Fiber Bragg Gratings Manufactured with UV Phase Mask and Direct Writing Techniques

Typically, fiber Bragg gratings (FBGs) used in single mode core pumped laser applications are manufactured using the phase mask technique because it allows to achieve low losses and excellent line shapes. However, this technique offers only limited flexibility for laser development due to the time consuming and cost-intensive fabrication of the phase masks. New direct inscription techniques offer flexibility but still show disadvantages, e.g., in terms of transmission losses that cause thermal limitations. Hence, this study aims to compare the transmission of FBGs manufactured by the line-by-line fs inscription (fs-lbl) with the UV phase mask technique.