Simultaneous Dispersion Flattening for Both Transverse Electric and Magnetic Modes

A novel silicon waveguide structure is proposed to simultaneous dispersion engineering of orthogonal modes. Ultraflat dispersion profiles are achieved for both the fundamental quasi-transverse-electric (TE) and transverse-magnetic (TM) modes by utilizing mode transition and anticrossing effects. Dispersion tailoring is carried out for both modes by tuning the structural parameters of the waveguide. There is only a low dispersion of <; ± 3.8 ps/(nm·km) over a 576-nm and a 817-nm bandwidth for the fundamental quasi-TE and quasi-TM modes, respectively. The reduced dispersion of the modes prevents pulse broadening and intensity reduction in each of the modes. The nonlinear parameters of the modes, the group velocity mismatch, and the characteristic lengths of walk-off and dispersion for both modes are also studied. It is discussed that mode coupling is feasible before the temporal separation of the modes can take place. Therefore, the proposed waveguide can provide highly efficient implementation of photonic applications based on polarization effects.