We propose a plasmonic superlattice with nonlinear Kerr medium in defect layer to realize slow light effect and demonstrate the group velocity control at telecom waveband (1550 nm) by peak intensity of input pulse. The tunable group velocity of surface plasmon polaritons is attributed to the change of dispersion of the superlattice caused by nonlinear Kerr effect. The method of controlling group velocity is analyzed by transfer matrix method based on characteristic impedance and confirmed by the finite-difference time-domain numerical simulation. Our method of control group velocity potentially applies in the tunable optics delay line.

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The strongly delayed wave with large bandwidth in a graphene-based grating waveguide has been reported previously. However, a clear slow wave performance in a simple graphene-based uniform waveguide has not been explored. Here, we analyzed for the first time a delayed surface wave in this waveguide. The strongly delayed wave with extremely large bandwidth can be dynamically controlled via the bias-voltage dependent optical properties of graphene. The simple waveguide is an excellent candidate for slow light applications because of easy fabrication, ultra-high slowdown factor, ultra-large bandwidth and conveniently tunable group velocity.

We propose metal-insulator-metal (MIM) plasmonic waveguide, in which metal is aluminum-doped zinc oxide (AZO) and insulator is air. The real part of relative dielectric constant is negative that is similar to the metal. Therefore, we call the AZO as metal. Owing to cutoff frequency of TM 0 model for the MIM waveguide being slightly larger than 193.5 THz, the MIM waveguide shows obviously slow light effect around the commonly used telecom frequency. Exploiting the dispersion relationship of MIM waveguide, we analyze the effect of core layer width for the MIM waveguide on slow group velocity, second-, and third-order dispersion. The core layer width of MIM waveguide is determined to simultaneously realize obviously slow light effect and the lower distortion for the pulse with width 200 fs, which is confirmed by simulation used the finite-difference time-domain method. The MIM waveguide potentially applied in optical delay lines is easily fabricated.

The effect of an applied electric field on the properties of strongly anisotropic a-axis single-crystal fiber is studied theoretically. We solve the electromagnetic field equations for strongly anisotropic a-axis single-crystal fiber and numerically analyze the mode characteristics of the fiber that conducts only the zeroth-order elementary mode. We discuss the effects that an applied electric field has on the refractive index anisotropy and the mode characteristics of the fiber that conducts only the zeroth-order elementary mode.