Harmonic Dissipative Soliton Resonance in a Large-Normal-Dispersion Erbium-Doped Fiber Laser

We experimentally demonstrated the harmonic mode-locking (HML) dissipative soliton resonance (DSR) pulses in an erbium-doped fiber laser with large normal dispersion utilizing an optical integrated module (OIM) mode locked by nonlinear polarization rotation (NPR) technique. With fixed intra-cavity parameters, various HML operations in the DSR regimes are available through adjusting the polarization controller (PC). Triggered by extra filtering loss due to broadened spectra under the stronger pump power or variations of polarization states, the multi-pulsing operation in the cavity assisted by pulse self-organizing enables the fundamental mode-locking (FML) DSR pulses to transform into HML conditions, where the newly formed HML DSR pulses are evolving in the same characteristics as the FML DSR pulses during each harmonic order. Under specific polarization states, the harmonic order is able to increase sequentially as the pump power ramps up with spectral redshift. Further tuning the PCs at a strong pump power will enable other harmonic states, of which the order could be up to 17th.