1 μJ Pulse Energy All-Fiber Thulium Doped Mode-Locked MOPA System

Abstract

Several different types of lasers already have been developed, which produce pulses at a μJ energy level at λ = 2 μm, such as a CPA-amplifier seeded by a combined Er:Tm:Ho-fiber laser [1]. Still, being split into two parts contributes negatively to the stability of those systems. Thus, an all-fiber MOPA system was developed, using CPA inside the fiber for generating pulses with an energy of 36.7μJ and a duration of 910fs[2]. Recently an all-fiber system with a pulse energy of ≥ 500 nJ and a pulse duration of 31 ps was published[3], which does not rely on CPA inside the fiber. Here we present an all-fiber MOPA system, based on the early idea of an all-fiber Tm-doped MOPA [ 4], capable of generating pulses with a pulse energy of ≈ 1 μJ at a repetition rate of ≈ 7.6MHz and a pulse duration of ≈ 2ps, without having to rely on CPA. This makes the laser design simpler and cost effective, while still retaining short pulses in the picosecond range.