Polarization-maintaining Yb-doped large-mode-area fully aperiodic large-pitch fibers.

Abstract

Based on a special large-pitch architecture that has already proved its single-mode single-polarization behavior in a passive configuration, two ytterbium-doped versions of such large-mode-area fibers have been fabricated and tested in both laser and amplification configurations for high-power laser source applications. Due to the high sensitivity of large-pitch fiber design to the active-core-to-passive-cladding index mismatch, the realization of a single-polarization structure is highly challenging. However, we report on the preservation of a polarization-maintaining feature. A linear polarization with an extinction ratio of 17dB is demonstrated for mode field diameters reaching up to 58μm as long as the single-modeness of the emitted signal is preserved.