L. M. Zhao

Dissipative soliton resonance in an all-normal-dispersion erbium-doped fiber laser

We report on the generation of 281.2 nJ mode locked pulses directly from an erbium-doped fiber laser mode-locked with the nonlinear polarization rotation technique. We show that apart from the conventional dissipative soliton operation, an all-normal-dispersion fiber laser can also emit square-profile dissipative solitons whose energy could increase to a very large value without pulse breaking.

Multi-wavelength dissipative soliton operation of an erbium-doped fiber laser

We report on the generation of multi-wavelength dissipative soliton (DS) in an all normal dispersion fiber laser passively mode-locked with a semiconductor saturable absorber mirror (SESAM). We show that depending on the strength of the cavity birefringence, stable single-, dual- and triple-wavelength DSs can be formed in the laser. The multi-wavelength soliton operation of the laser was experimentally investigated, and the formation mechanisms of the multi-wavelength DSs are discussed.

Dissipative vector solitons in a dispersionmanaged cavity fiber laser with net positive cavity dispersion.

We report on the experimental observation of gain-guided vector solitons (GGVSs) in a dispersion-managed fiber laser mode-locked with a semiconductor saturable absorber mirror (SESAM). Both the frequency-locked and phase-locked GGVS were observed. In addition, formation of multiple GGVSs and GGVS harmonic mode-locking were also experimentally revealed. Numerical simulations confirmed the GGVS formation in the fiber lasers.

Soliton collapse and bunched noise-like pulse generation in a passively mode-locked fiber ring laser

A passively mode-locked soliton fiber ring laser with dispersion managed cavity is reported. The laser emits intense bunched noise-like pulses including the transform limited pulses. The optical spectrum of the laser emission has a bandwidth as broad as 32.10 nm. It was found that purely depending on the linear cavity phase delay the laser could be switched between the soliton operation and the noise-like pulse emission. Numerical simulations showed that the laser emission was caused by the combined effect of soliton collapse and positive cavity feedback in the laser.

Coherent energy exchange between components of a vector soliton in fiber lasers.

We report on the experimental evidence of four wave mixing (FWM) between the two polarization components of a vector soliton formed in a passively mode-locked fiber laser. Extra spectral sidebands with out-of-phase intensity variation between the polarization resolved soliton spectra was firstly observed, which was identified to be caused by the energy exchange between the two soliton polarization components. Other features of the FWM spectral sidebands and the soliton internal FWM were also experimentally investigated and numerically confirmed.We report on the experimental evidence of four wave mixing (FWM) between the two polarization components of a vector soliton formed in a passively mode-locked fiber laser. Extra spectral sidebands with out-of-phase intensity variation between the polarization resolved soliton spectra was firstly observed, which was identified to be caused by the energy exchange between the two soliton polarization components. Other features of the FWM spectral sidebands and the soliton internal FWM were also experimentally investigated and numerically confirmed.

Dark pulse emission of a fiber laser

We report on the dark pulse emission of an all-normal dispersion erbium-doped fiber laser with a polarizer in cavity. We found experimentally that apart from the bright pulse emission, under appropriate conditions the fiber laser could also emit single or multiple dark pulses. Based on numerical simulations we interpret the dark pulse formation in the laser as a result of dark soliton shaping.

Vector dark domain wall solitons in a fiber ring laser

We observe a novel type of vector dark soliton in a fiber ring laser. The vector dark soliton consists of stable localized structures separating the two orthogonal linear polarization eigenstates of the laser emission and is visible only when the total laser emission is measured. Numerical simulations based on the coupled complex Ginzburg-Landau equations have well reproduced the results of the experimental observation.

Noise-like pulse in a gain-guided soliton fiber laser

We report on the operation of a passively mode-locked fiber ring laser made of purely positive dispersion fibers and mode-locked by using the nonlinear polarization rotation technique. It was experimentally found that apart from the gain-guided soliton operation the laser can also emit a kind of noise-like pulse. We show numerically that the noise-like pulse emission is caused by the peak power clamping effect of the laser cavity on the gain-guided soliton.

Generation of 47-fs pulses directly from an erbium-doped fiber laser

We show both numerically and experimentally that through appropriately selecting the output coupling position and strength in a mode-locked fiber laser, one can effectively manage the nonlinearity of the cavity. By implementing the technique together with cavity dispersion management in an erbium-doped fiber laser, we have achieved stable mode-locked pulses with a single-pulse energy of 2.08 nJ and pulse width of 46.2 fs directly from the laser.

Induced solitons formed by cross-polarization coupling in a birefringent cavity fiber laser

We report on the experimental observation of induced solitons in a passively mode-locked fiber ring laser with a birefringence cavity. Owing to the cross coupling between the two orthogonal polarization components of the laser, it was found that if a soliton was formed along one cavity polarization axis, a weak soliton was also induced along the orthogonal polarization axis, and depending on the net cavity birefringence, the induced soliton could have either the same or different center wavelengths to that of the inducing soliton. Moreover, the induced soliton always had the same group velocity as that of the inducing soliton. They formed a vector soliton in the cavity. Numerical simulations confirmed the experimental observations.