Luming Zhao

Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker

Due to its unique electronic property and the Pauli blocking principle, atomic layer graphene possesses wavelength-independent ultrafast saturable absorption, which can be exploited for the ultrafast photonics application. Through chemical functionalization, a graphene-polymer nanocomposite membrane was fabricated and first used to mode lock a fiber laser. Stable mode locked solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength have been directly generated from the laser. We show that graphene-polymer nanocomposites could be an attractive saturable absorber for high power fiber laser mode locking.

Large energy mode locking of an erbium-doped fiber laser with atomic layer graphene

We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.

Graphene mode locked, wavelength-tunable, dissipative soliton fiber laser

Atomic layer graphene possesses wavelength-insensitive ultrafast saturable absorption, which can be exploited as a “full-band” mode locker. Taking advantage of the wide band saturable absorption of the graphene, we demonstrate experimentally that wide range (1570–1600 nm) continuous wavelength tunable dissipative solitons could be formed in an erbium doped fiber laser mode locked with few layer graphene.

Gain-guided soliton in a positive group-dispersion fiber laser

We report on the operation of a passively mode-locked fiber ring laser made of purely normal dispersive fibers. Self-started mode locking can still be achieved in the laser by use of the nonlinear polarization rotation technique, and the mode-locked pulse has large pulse energy, strong frequency chirp, and a mode-locked spectral width limited by the effective laser gain bandwidth. Furthermore, we show that the operation of the laser can be well described by an extended Ginzburg-Landau equation model that governs the soliton dynamics of fiber lasers.

Compact graphene mode-locked wavelength-tunable erbium-doped fiber lasers: from all anomalous dispersion to all normal dispersion

Soliton operation and soliton wavelength tuning of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated under various cavity dispersion conditions. It was shown that not only wide range soliton wavelength tuning but also soliton pulse width variation could be obtained in the fiber lasers. Our results show that the graphene mode locked erbium-doped fiber lasers provide a compact, user friendly and low cost wavelength tunable ultrashort pulse source.

Dissipative soliton operation of an ytterbium-doped fiber laser mode locked with atomic multilayer graphene

Mode locking of an ytterbium-doped fiber laser with atomic multilayer graphene is, to the best of our knowledge, experimentally demonstrated for the first time. Dissipative solitons with duration of 580 ps at 1069.8 nm were generated. Since graphene can also be used to mode lock erbium-doped fiber lasers, our result shows that graphene indeed has wavelength-independent saturable absorption, which could be exploited to mode lock fiber lasers with various operating wavelengths.

Vector dissipative solitons in graphene mode locked fiber lasers

Vector soliton operation of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated. Either the polarization rotation or polarization locked vector dissipative solitons were experimentally obtained in a dispersion-managed cavity fiber laser with large net cavity dispersion, while in the anomalous dispersion cavity fiber laser, the phase locked nonlinear Schrodinger equation (NLSE) solitons and induced NLSE soliton were experimentally observed. The vector soliton operation of the fiber lasers unambiguously confirms the polarization insensitive saturable absorption of the atomic layer graphene when the light is incident perpendicular to its 2-dimentional (2D) atomic layer.

Dissipative soliton generation in Yb-fiber laser with an invisible intracavity bandpass filter

We report on dissipative soliton (DS) generation in an Yb-doped (YDF) fiber laser passively mode locked with the nonlinear polarization rotation (NPR) technique. We found that even without the insertion of a physical bandpass filter in the cavity, not only could DSs be automatically formed in the laser but also the formed DSs have a spectral bandwidth that is far narrower than the Yb-fiber gain bandwidth. Numerical simulations well reproduced the experimental observations. Our results suggest that a physical intracavity bandpass filter is not a crucial component for the generation of DSs in all-normal-dispersion YDF lasers mode locked with the NPR technique.

Gain-guided solitons in dispersion-managed fiber lasers with large net cavity dispersion

Gain-guided solitons are experimentally observed in dispersion-managed fiber lasers with large net positive group-velocity dispersion. It is shown that formation of the soliton is a robust feature of the lasers. Numerical simulations also confirmed the experimental results.

Atomic multi-layer graphene for dissipative soliton generation in Ytterbium-doped fiber laser

Atomic multi-layer graphene film as a saturable absorber was first demonstrated to be able to mode lock Ytterbium-doped fiber lasers at wavelength around 1 um. Determined by the operation conditions, single or multiple dissipative solitons (DSs) can be generated in the fiber lasers. DSs with pulse duration of 550∼630 ps were generated. As graphene can also be used to mode lock erbium-doped fiber lasers at wavelength around 1.55 um, our result shows that graphene has indeed wavelength-independent saturable absorption, which could be exploited to mode lock fiber lasers with various operating wavelengths.