High power cylindrical vector beam fiber laser by integrating oscillator and amplifier

Cylindrical vector beams (CVBs) have attracted immense recent attention for material processing and particle manipulation. High power output is the base of CVB lasers for those applications. The traditional path to obtain high power CVB laser is the cooperation of the high-order mode (HOM) amplifier and CVB seed source, which is a complex and non-integrated system. This work proposed a compact high power CVB laser with an amplifier and an oscillator integrated into one fiber cavity. In the fiber cavity, the fundamental mode is resonant, and the HOM escapes in a leaky mode. Tunable output power and high slope efficiency of the fiber laser are realized due to the special structure. Numerical simulations are performed to investigate the tunability of output power, which agree well with the experiment results. The maximum efficiency of single-sided output and total output of the laser can reach 16.20% and 25.03%, respectively, corresponding to maximum output power of 1.83W and 2.93W. The purity of CVB output from the laser can reach 97.9%. This leaky mode output fiber laser provides a new scheme for generating high power HOM laser and inspires research of HOM control in fiber.