Cylindrical vector pulse generation from mode-locked fiber laser with few-mode fiber grating

Cylindrical vector beams (CVBs) have been widely used in many applications, such as optical tweezers, surface plasmon resonance and material processing, because of its symmetric intensity and polarization. Few-mode fiber grating (FMFG) as the high order mode selector has the advantages of high-efficiency, low cost and all-fiber structure. We demonstrate cylindrical vector pulse generation from a mode-locked fiber laser with few-mode fiber grating. Reflection spectra of a few-mode fiber Bragg grating are simulated numerically and then measured experimentally under different bending conditions.