193-GHz 53-W Subpicosecond Pulse Source

Abstract

We present a light source that can generate a pulse train with an extremely high repetition rate, tens of watts of average output power, and a low-divergence output beam. This unique combination of system characteristics is achieved with single-stage amplification of a passively harmonically mode-locked semiconductor disk laser in a tapered Yb-doped double-clad fiber. With the short-length tapered fiber amplifier an amplification factor >17 dB is reached, while preserving the 930-fs pulse duration of the semiconductor disk laser. The demonstrated pulse source with a beam quality factor <2 enables efficient coupling into single-mode fibers for nonlinear optical experiments and ultracoarse frequency comb generation.

Recent advances in VECSELs

“…Such high repetition rates for pulsed VECSELs are particularly attractive for optical transmission schemes. Recently, a high-power fibre-amplified 193 GHz sub-picosecond pulse source with 53 W output was also demonstrated which allows efficient coupling into single-mode fibers and has the potential to be used for ultracoarse frequency comb generation and nonlinear optical experiments (Saarinen et al 2015a).…”

Accurate modeling of high-repetition rate ultrashort pulse amplification in optical fibers

“…The complexity of fiber based MOPA systems vary greatly depending on applications. Some schemes employ several amplification stages 13 14 15 16 with intermediate pulse shaping 9 13 15 16 , whereas other schemes just rely on one amplification stage 17 18 19 . Regardless of the specific system design, the active fiber in the amplifier is the main temporal and spectral pulse shaping element owing to pump-dependent and spectrally varying gain distribution along the fiber, pulse interaction with co-propagating amplified spontaneous emission (ASE), dispersion, as well as non-resonant and resonant components of nonlinearities.…”