Suppression of dual-peak Raman noise by chirped tilted fiber Bragg gratings

Chirped Tilted Fiber Bragg Gratings (CTFBG) are critical fiber devices used to suppress Stimulated Raman Scattering (SRS) in high-power continuous fiber lasers. To reduce the difficulty of fabrication, optimize the CTFBG transmission spectrum parameters, and enhance its Raman noise suppression capability in the application of higher powers, we designed a dual-angle CTFBG targeting the dual peaks of the Raman gain spectrum. This design, featuring tilt angles of 2.9° and 4.2°, corresponds to transmission spectrum center wavelengths at 13.2THz and 14.7THz. Compared to conventional single-angle CTFBG, the dual-angle CTFBG shows excellent Raman suppression capabilities at both 13.2THz and 14.7THz Raman gain peaks.