Fig. 1. Raman gain spectrum of fusion silica^[9]

Fig. 2. Simulation results of the transmission spectrum of LPFG

Fig. 3. Schematic of LPFG lithography system

Fig. 4. Measured transmission spectrum of fabricated LPFG

Fig. 5. Schematic of experimental setup for filtering SRS using LPFG

Fig. 6. Output spectra of optical fiber oscillator. (a) Output Spectra without LPFG; (b) output spectra with LPFG; (c) comparison of SRS spectra with and without LPFG; (d) SRS rejection ratio with LPFG

Fig. 7. Output performance of fiber laser with and without LPFG. (a) Comparison of total output power of fiber laser; (b) comparison of signal ratio; (c) comparison of Stokes power; (d) comparison of signal power