Compact all-fiber ring femtosecond laser with high fundamental repetition rate.

A 165-fs all-fiber ring laser is demonstrated with a fundamental repetition rate of 235 MHz based on a 5.7-cm-long Er(3+)/Yb(3+) codoped phosphate glass fiber and a technique of nonlinear polarization evolution. In order to further enhance the fundamental repetition rate and compact the structure of the all-fiber laser, an optical integrated module is designed. By employing this novel optical module, a much more compact 105-fs mode-locking all-fiber ring laser, operating at a 325 MHz fundamental repetition rate, is realized.