Ultrahigh Birefringent Nonlinear Slot Silicon Microfiber With Low Dispersion

Abstract

A new simple structure of ultrahigh birefringent and ultrahigh nonlinear slot silicon microfiber with highly efficient dispersion reduction is proposed and numerically simulated using the full-vector finite-element method with anisotropic perfectly matched layers. Benefiting from the slot effect-induced sub-wavelength mode confinement, ultrahigh birefringence up to the order of $10^{\mathrm {{-1}}}$ can be realized within a wide wavelength range from 1.4 to 1.7 $\mu \text{m}$ , which is comparable with the results in these ultrahigh birefringent photonic crystal fibers, but cannot be achieved in traditional microfibers. Meanwhile, the nonlinear coefficients of quasi-TE mode and quasi-TM mode at the wavelength of 1.55 $\mu \text{m}$ are as high as 969.58 $\text{W}^{\mathrm {{-1}}}\text{m}^{\mathrm {{-1}}}$ and 156.74 $\text{W}^{\mathrm {{-1}}}\text{m}^{\mathrm {{-1}}}$ , respectively. Furthermore, the dispersion value of quasi-TE mode at 1.55 $\mu \text{m}$ can be decreased from $1.2358\times 10^{\mathrm {{3}}}$ ps/(nm $\cdot $ km) to 0 ps/(nm $\cdot $ km) simply by modifying the slot size. Owing to its excellent performance, the proposed slot silicon microfiber will have great potential for polarization maintaining nonlinear signal processing applications.