Coherent pulse stacking amplification using low-finesse Gires-Tournois interferometers.

We demonstrate a new technique of coherent pulse stacking (CPS) amplification to overcome limits on achievable pulse energies from optical amplifiers. CPS uses reflecting resonators without active cavity-dumpers to transform a sequence of phase- and amplitude-modulated optical pulses into a single output pulse. Experimental validation with a single reflecting resonator demonstrates a near-theoretical stacked peak-power enhancement factor of ~2.5 with 92% and 97.4% efficiency for amplified nanosecond and femtosecond pulses. We also show theoretically that large numbers of equal-amplitude pulses can be stacked using sequences of multiple reflecting resonators, thus providing a new path for generating very high-energy pulses from ultrashort pulse fiber amplifier systems.