Toward higher-order passive harmonic mode-locking of a soliton fiber laser

Abstract

We report >13 MHz/mW pump power efficiency in increasing the repetition rate of passive harmonic mode-locking by engineering the soliton pulse energy in Er fiber lasers incorporating carbon nanotube saturable absorber. Stable pulses with a ∼5 GHz repetition rate and 40 dB of super-mode suppression are demonstrated with only ∼400 mW pump power in a single-clad fiber laser.

SnSe2 Nanosheets for Subpicosecond Harmonic Mode‐Locked Pulse Generation

“…Among them, only multi‐pulse operation can effectively improve the RPR of mode‐locking pulse without reducing the cavity length. Harmonic mode locking is a special multi‐pulse operation . When the laser operates in fundamental mode locking, the RPR of the pulse corresponds to the cavity length.…”

“…However, multi‐pulse state with uniform time interval can be obtained under certain pump power and polarization state . In this case, the RPR of the pulse is an integer multiple of the RPR corresponding to the length of the fiber resonator cavity, namely, harmonic mode locking . High RPR ultra‐short pulse can be widely used in the fields of fiber sensing, ultra‐fast optics, optical communication, and biomedicine, etc .…”

“…In this case, the RPR of the pulse is an integer multiple of the RPR corresponding to the length of the fiber resonator cavity, namely, harmonic mode locking . High RPR ultra‐short pulse can be widely used in the fields of fiber sensing, ultra‐fast optics, optical communication, and biomedicine, etc . However, some drawbacks, such as low damaged threshold, unsuitable cavity dispersion, and limited pump power, prevent achieving high RPR ultra‐short pulse based on real SAs.…”

Harmonic Mode-Locked Fiber Laser based on Photonic Crystal Fiber Filled with Topological Insulator Solution

“…However, mode-locked fiber lasers based on NPR and the NALM technique are intrinsically environmentally unstable. Therefore, researchers have strong motivations investigate HML in passively mode-locked fiber lasers by real saturable absorbers (SAs) [11][12][13][14][15][16], such as semiconductor saturable absorbers (SESAM), single-walled carbon nanotube (SWNT) and graphene. However, these SAs also possess some inherent drawbacks.…”

Passively harmonic mode-locked erbium-doped fiber laser at a 580 MHz repetition rate based on carbon nanotubes film

“…Jun et al first obtained a 943 MHz pulse train at the 34th harmonics with excellent noise performance under 195 mW pump power [26] . Furthermore, through engineering the dispersion of the cavity, 4.9 GHz pulses, corresponding to the 128th HML was finally realized under 395 mW pump power with 40 dB super-mode suppression ratio (SMSR) [27] . However, the structure is considerably conditional on the special fiber devices, which will bring additional complexity to the system [28] .…”