Abstract

Pulsed lasers operating in the 2 μm spectral region are now widely used in material processing [1], remote sensing [2] or for nonlinear frequency conversion deeper in the mid-IR where sub-ns pulse durations and high peak powers are required. Driven by these demands, substantial progress has recently been made in the improvement of thulium-doped lasers and amplifiers. Even if modelocked thulium-doped fibre (TDF) lasers are the widespread solution to address these needs, their cavity length generally prevents output repetition rates to be higher than a few tens of MHz. With the advent of optical communications in the 2 μm band and other important applications such as frequency comb metrology, a gigahertz repetition rate fibre source near 2 μm is a desired component. Here, we describe an all-fibre pulsed source based on parametric conversion followed by thulium amplification able to deliver picosecond long pulses at gigahertz repetition rates. Additionally, the pulse duration and rate can be easily tuned and the central wavelength can be freely selected in the range 1930–1980 nm. A maximum power of 1.2 W peak and 115 mW average is obtained at 1960 nm.

© 2015 IEEE