High-gain solid-state and fiber amplifier-chain for high-power coherent communication

We report on the experimental results of a dual-stage amplifier combining a Nd-doped double-clad fiber and a Nd-doped YAG crystal. We obtained up to 3.5-W single-mode single-frequency output power with 28-dB gain. This is, to the best of our knowledge, the first demonstration of a dual-stage amplifier combining doped fibers and solid-state amplifiers.