title: Long-term stable coherent beam combination of independent femtosecond Yb-fiber lasers.
abstract: We demonstrate coherent beam combination between independent femtosecond Yb-fiber lasers by using the active phase locking of relative pulse timing and the carrier envelope phase based on a balanced optical cross-correlator and extracavity acoustic optical frequency shifter, respectively. The broadband quantum noise of femtosecond fiber lasers is suppressed via precise cavity dispersion control, instead of complicated high-bandwidth phase-locked loop design. Because of reduced quantum noise and a simplified phase-locked loop, stable phase locking that lasts for 1 hour has been obtained, as verified via both spectral interferometry and far-field beam interferometry. The approach can be applied to coherent pulse synthesis, as well as to remote frequency comb connection, allowing a practical all-fiber configuration.
authors.forename: Haochen
authors.initials: H
authors.lastname: Tian
authors.forename: Youjian
authors.initials: Y
authors.lastname: Song
authors.forename: Fei
authors.initials: F
authors.lastname: Meng
authors.forename: Zhanjun
authors.initials: Z
authors.lastname: Fang
authors.forename: Minglie
authors.initials: M
authors.lastname: Hu
authors.forename: Chingyue
authors.initials: C
authors.lastname: Wang