We have investigated the propagation dynamics of super-Gaussian optical beams in fractional Schrödinger equation. We have identified the difference between the propagation dynamics of super-Gaussian beams and that of Gaussian beams. We show that, the linear propagation dynamics of the super-Gaussian beams with order m > 1 undergo an initial compression phase before they split into two sub-beams. The sub-beams with saddle shape separate each other and their interval increases linearly with propagation distance. In the nonlinear regime, the super-Gaussian beams evolve to become a single soliton, breathing soliton or soliton pair depending on the order of super-Gaussian beams, nonlinearity, as well as the Lévy index. In two dimensions, the linear evolution of super-Gaussian beams is similar to that for one dimension case, but the initial compression of the input super-Gaussian beams and the diffraction of the splitting beams are much stronger than that for one dimension case. While the nonlinear propagation of the super-Gaussian beams becomes much more unstable compared with that for the case of one dimension. Our results show the nonlinear effects can be tuned by varying the Lévy index in the fractional Schrödinger equation for a fixed input power.

We report on the observation of bound states of gain-guided solitary pulses (GGSPs) in a dispersion-managed erbium-doped fiber laser. Despite the fact that the GGSP is a chirped pulse and there is strong pulse stretching and compression along the cavity in the laser, the bound GGSPs observed have a fixed pulse separation, which is invariant to the pump strength change. Numerical simulation confirmed the experimental observations and further showed that not only the pulse separation but also the relative phase difference between the bound GGSPs remained fixed along the cavity.

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We report on the observation of central wavelength dynamics in an erbium-doped fiber ring laser by using the nonlinear polarization rotating technique. The evolution of central wavelength with the laser operation state was observed experimentally. Numerical simulations confirmed the experimental observation and further demonstrated that the dynamics of wavelength evolution is due to the combined effects of fiber birefringence, fiber nonlinearity, and cavity filter.

The propagation of decelerating Airy pulses in non-instantaneous cubic medium is investigated both theoretically and numerically. In a Debye model, at variance with the case of accelerating Airy and Gaussian pulses, a decelerating Airy pulse evolves into a single soliton for weak and general non-instantaneous response. Airy pulses can hence be used to control soliton generation by temporal shaping. The effect is critically dependent on the response time, and could be used as a way to measure the Debye type response function. For highly non-instantaneous response, we theoretically find a decelerating Airy pulse is still transformed into Airy wave packet with deceleration. The theoretical predictions are confirmed by numerical simulations.

Abstract-A circularly polarized (CP) substrate integrated waveguide (SIW) cavity-backed antenna based on dual concentric, orthogonal slot split ring resonators is proposed and experimentally studied. The circularly polarized wave is generated by two split ring-slots etched in the upper metal layer of the SIW cavity resonator. These two slots are excited by a coaxial probe located in the gap of the external slot split ring to radiate the right-handed circularly polarized (RHCP) wave. By rotating the dual split slot ring resonators and the probe by 45 degrees relative to the backed cavity, a better match characteristic and a slightly higher radiation gain are obtained. Because of the concentricity of radiant split ring slots, the beamwidth of the circular polarization is obviously increased. From the experimental results, the impedance bandwidth was 10.8% for the reflection coefficient less than −10 dB, the axial ratio (AR) bandwidth was 1.54% for the AR less than 3 dB, and the RHCP gain was 4.44 dBic. Moreover, the 3-dB axial ratio beamwidth at the centre frequency of 10.40 GHz has been extended to 142 • in the angular range from −78 • to +64 • .