Harmonic Condensed Soliton Phase in a Mode-Locked Fiber Laser

A new category of harmonic mode-locked pattern is reported in passively mode-locked fiber laser (MLFL). The laser base on gold nanorods (GNRs) as a mechanism to trigger mode locking. By adjusting polarization controllers and pumping power, including fundamental mode-locked pulse, condensed soliton phase, soliton rain, harmonic condensed soliton phase have been observed. The harmonics condensed soliton phase were experimentally verified for the first time in the MLFL. The experimental results explained the conditions for the generation of condensed soliton phase and extend the pulse type of harmonic mode-locking (HML).