Abstract

An intense research effort has been channelled into improving mode-locked Yb-fiber oscillators in recent years. Despite efforts in all-normal dispersion oscillators, dispersion management is evidently necessary to reach pulse durations below 50 fs. This is implemented most commonly with bulk optical components in Yb-doped fiber lasers. Increased robustness remains a valuable trait, for which all-fiber-integration is highly desirable. Photonic crystal fibers (PCF) with anomalous dispersion have small mode field diameters, enhancing nonlinear effects and usually are birefringent. The first mode-locked laser to incorporate a PCF was reported in 2002 [1]. However, mode-locking was not self-starting owing to the residual birefringence of the PCF. Since then, a number of dispersion-managed Yb-doped fiber lasers using PCFs and all-fiber-integrated lasers have been reported. After 10 years, no all-fiber-integrated Yb-fiber laser has been demonstrated to support pulses below 60 fs [2].

© 2013 IEEE