Spectral shaping of an ultrafast ytterbium fiber laser via a passive intracavity optical filter: a simple and reliable route to sub-45 fs pulses

We investigate the use of passive intracavity optical filters for controlling the laser output spectrum of a polarization-mode-locked, ultrafast ytterbium fiber laser. The overall lasing bandwidth is increased or extended by strategic choice of the filter cutoff frequency. Overall laser performance, including pulse compression and intensity noise, is investigated for both shortpass and longpass filters with a range of cutoff frequencies. The intracavity filter not only shapes the output spectra, but also provides a route for overall broader bandwidths and shorter pulses in ytterbium fiber lasers. These results demonstrate that spectral shaping with a passive filter is a useful tool to routinely achieve sub-45 fs pulse durations in ytterbium fiber lasers. (c) 2023 Optica Publishing Group

Automated summary

We investigate the use of passive intracavity optical filters for controlling the laser output spectrum of a polarization-mode-locked, ultrafast ytterbium fiber laser. The filter cutoff frequency can increase or extend the overall lasing bandwidth. Shortpass and longpass filters at different cutoff frequencies are studied for their impact on laser performance, including pulse compression and intensity noise. The intracavity filter not only shapes the output spectra, but also enables broader bandwidths and shorter pulses in ytterbium fiber lasers, demonstrating its usefulness in achieving sub-45 fs pulse durations.