  External driving of passive, nonlinear optical resonators has emerged over
the past decade as a novel route for the generation of ultrashort optical
pulses and corresponding broadband frequency combs. Whilst the pulse formation
dynamics in such systems differ dramatically from those manifesting themselves
in conventional mode-locked lasers, the demarcation between the two
traditionally distinct paradigms has recently begun to blur, with
demonstrations of hybrid systems incorporating both external driving and active
media shown to offer specific advantages. Here we explore a new pathway for
ultrashort pulse generation at the interface of externally-driven passive
resonators and lasers. By leveraging the nonlinear Raman gain inherent to fused
silica, we achieve deterministic generation of low-noise dissipative solitons
with durations well below 100 fs via phase-coherent pulsed driving of
resonators made of standard, commercially-available optical fibre. We explore
and explain the physics of the new dissipative Raman soliton states,
identifying scaling laws that govern the pulses' characteristics and that allow
output repetition rates to be scaled at will without influencing the soliton
duration. The scheme explored in our work enables the shortest ever pulses
generated in resonators (active or passive) made from a single
commercially-available optical fibre, and it has the potential to be
transferred into a chip-scale format by using existing dispersion-engineered
silica microresonators.
