Femtosecond harmonic mode-locking of a fiber laser at 327 GHz using a bulk-like, MoSe_2-based saturable absorber

Abstract

We experimentally demonstrate the use of a bulk-like, MoSe₂-based saturable absorber (SA) as a passive harmonic mode-locker for the production of femtosecond pulses from a fiber laser at a repetition rate of 3.27 GHz. By incorporating a bulk-like, MoSe₂/PVA-composite-deposited side-polished fiber as an SA within an erbium-doped-fiber-ring cavity, mode-locked pulses with a temporal width of 737 fs to 798 fs can be readily obtained at various harmonic frequencies. The fundamental resonance frequency and the maximum harmonic-resonance frequency are 15.38 MHz and 3.27 GHz (212th harmonic), respectively. The temporal and spectral characteristics of the output pulses are systematically investigated as a function of the pump power. The output pulses exhibited Gaussian-temporal shapes irrespective of the harmonic order, and even when their spectra possessed hyperbolic-secant shapes. The saturable absorption and harmonic-mode-locking performance of our prepared SA are compared with those of previously demonstrated SAs that are based on other transition metal dichalcogenides (TMDs). To the best of the authors' knowledge, the repetition rate of 3.27 GHz is the highest frequency that has ever been demonstrated regarding the production of femtosecond pulses from a fiber laser that is based on SA-induced passive harmonic mode-locking.

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

“…Driven by these efforts, mode‐locked fiber lasers based on other layered TMDCs and their derivatives including MoSe 2 , MoTe 2 , WTe 2 , WSe 2 , MoSe 2 , SnS 2 , ReS 2 , In 2 Se 3 , InS, TiS 2 , PtS 2 , PtSe 2 , and HfS 2 , have also developed rapidly, as shown in Table . It can be seen that for these lasers, the minimum pulse width is 67 fs, maximum output power is 212 mW, and maximum repetition rate is 8.82 GHz .…”

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.…”

Broadband saturable absorption and exciton-exciton annihilation in MoSe2 composite thin films

“…2D materials have been the focus of research in many fields due to their novel physical, chemical, optical, and mechanical properties. As a big branch of 2D materials, layered transition metal dichalcogenides (TMDs) such as MoS 2 , MoSe 2 , WS 2 , WSe 2 and WSn 2 etc., are reported to possess improved optical performance, such as photoluminescence, when compared to their bulk counterparts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Particularly, the nonlinear optical experiments indicate that 2D liquid-phase-exfoliated MoSe 2 has strong saturable absorption [17,18].…”