Generation of High-Power Femtosecond Cylindrical Vector Beam in an All-Fiber Mamyshev Oscillator

Cylindrical vector beams (CVBs) have attracted significant attention due to their axial symmetry in both polarization and field intensity. However, directly generating high average power ultrashort CVBs in an all-fiber architecture remains a considerable technical challenge. Herein, we integrate all-fiber Mamyshev oscillator (MO) with mode selective coupler (MSC) to generate CVBs exhibiting high average power and short pulse duration. Optimization of the intracavity polarization state and intracavity nonlinear effects enables the generation of CVBs with an average power of 500 mW and the corresponding pulse width compressed to 251 fs. To our knowledge, this is the first demonstration of high average power, femtosecond CVBs generation in an all-fiber MO. Further optimization in pump power and gain management allows for the generation of harmonic CVBs up to the ninth-order, corresponding to a repetition rate of approximately 210 MHz. These results present an effective approach for generating CVBs in all-fiber lasers, significantly advancing the development of high average power, ultrashort CVBs, and providing an important experimental foundation for the exploration of high repetition frequency CVBs.