Single-cavity bidirectional Raman-assisted mode-locked fiber laser

Bidirectional mode-locked fiber lasers are promising dual-comb light sources. Stimulated Raman scattering (SRS) effect can significantly extend the wavelength range of mode-locked fiber lasers. In this work, we propose and demonstrate a single-cavity bidirectional Raman-assisted mode-locked fiber laser based on nonlinear multimode interference effect. By adjusting the polarization of the cavity, we obtain synchronous and asynchronous pulse trains in counterclockwise (CCW) direction and clockwise (CW) direction, as a consequence of changes in the dispersion and nonlinear effects. Due to the extension of the wavelength range of single-cavity bidirectional mode-locked fiber laser, we believe that this work will hold potential for future applications in dual-comb spectroscopy, asynchronous sampling and other areas.