High efficiency, high repetition rate, all-fiber picoseconds pulse MOPA source with 125 W output in 15 urn fiber core

摘要

A passive mode-locked fiber laser-delivered 13 ps pulse is saturatedly amplified with a four-stage amplifier chain. 125 W high power all-fiber picoseconds pulse laser is demonstrated in a 15-um fiber core, and the optical-to-optical conversion efficiency of the main amplifier is up to 86.12 %. A home-made (6 + 1) × 1 fiber combiner is used to couple the pump light and signal light into the gain double cladding fiber. In order to suppress the nonlinear effects in high-power picosecond fiber amplifiers, the repetition rate of the seed pulse is increased from 60 MHz to ～ 1 GHz; also the gain fibers are advisably selected. The amplified output spectrum is symmetrically broadened to several nanometers due to self-phase modulation (SPM). No stimulated Raman scattering (SRS), amplified spontaneous emission (ASE) and residual pump light are observed and the optical signal-to-noise ratio is more than 30 dB. The all-fiber picoseconds MOPA laser in this report can be easily performed with the conventional fiber handing equipments, and it has great potential to be applied as pump source in the fields of optical parametric oscillator, laser frequency-doubling and super-continuum generation.