Low Dispersion Slow Light in Slot Waveguide Grating

A novel and simple one-dimensional waveguide grating with two parallel air slots is proposed to support low dispersion slow light. Due to more structural tuning freedoms provided by introduction of the slots, it is easier to achieve the perfect flat and straight slow light mode dispersion curve. Low group dispersion of only 3.38 ps 2 /mm with a slow light group index of 13 is obtained in a plane wave expansion calculation, which denotes a wide bandwidth of 13.2 nm. This result is also proved by finite-difference time-domain simulation in which the output pulse relative distortion is only 0.96% towards the input pulse.