Generation of cylindrical vector beams with noise-like pulses and their bound state in a ytterbium-doped fiber laser

We experimentally investigate the generation of cylindrical vector beams with noise-like pulses (NLPs) and their bound state in a ytterbium-doped fiber laser. A homemade mode-selective coupler serves as the mode converter, which consists of a pre-tapered single-mode fiber and a two-mode fiber fabricated using a weak-fusion technique, exhibiting an insertion loss of approximately 0.55 dB. Switching between radially and azimuthally polarized beams was achieved by adjusting the polarization controller, with measured mode purity exceeding 94.5% across different operational states. Numerical simulations were employed to elucidate the formation mechanisms of both NLPs and their bound states. The demonstrated laser system shows promising potential for applications in laser material processing and mode-division multiplexing systems.