115  W fiber laser with an all solid-structure and a large-mode-area multicore fiber

Abstract

We investigate mode-area scaling by means of supermode operation in an all-solid multicore fiber. To obtain a large-mode area (LMA), we designed and fabricated an active double-clad multicore fiber, where each ytterbium-doped core is 19 μm in diameter and has a numerical aperture of 0.067, comparable to the core of the largest available commercial LMA fibers. The six large cores are stacked tightly in a ring structure to enable phase locking of the core fields and supermode operation. The fiber laser performance was investigated in a linear laser cavity with an external Talbot resonator for mode selection. The highest output power achieved was 115 W with an overall 61% slope efficiency corresponding to the pump power. The measured M was 1.43 for the central lobe with nearly 70% of the total power.

Thermal Effects on Modal Properties of Dual-Core Yb-Doped Fibers

“…A possible route to further power scaling is to incorporate a number of amplifying cores in each fiber [11]- [13]. The individual cores may then be kept sufficiently small to maintain single-mode guidance, whereas the total core area could in principle be very large.…”

High-power, high-brightness solid-state laser architectures and their characteristics

“…The central lobe contained close to 70% of the total power and had an M 2 of 1.43. The in-phase supermode was favored by using a kind of Talbot resonator that produced differently strong feedback for the supermodes depending on the spacing between fiber end and mirror [188]. Using such MCF with strong coupling and tiled-aperture combining greatly simplifies the optical setup and does not need an external phase control, but so far it seems to be difficult to exceed the (diffractionlimited) powers that can be achieved with a single-core fiber.…”

7-core Yb-doped fiber laser with femtosecond pulse inscribed fiber Bragg gratings

“…The fundamental in-phase supermode selection in a coupled 19-core Er/Yb fiber laser was performed using a free-space Talbot cavity in [3]. The application of a large-mode-area Yb-doped MCF with coupled cores and Talbot resonator allowed one to obtain 115 W of in-phase mode with the slope efficiency of 61% with respect to the pump power in [4]. New configurations of continuous MCF-based Raman fiber lasers were reported in [5,6], where femtosecond pulse writing technology was used to form complex reflective elements in the cores.…”