Slow light will play an important role for all optical network communication in the future.A design of out-of-plane slow light filter based on resonance induced transparency of zero contrast grating is proposed

which combines excellent transmission filtering function and slow light effect.The influences of etch depth and grating period on the slow light filtering performance is analyzed.It is noted that the change of the etching depth can significantly reduce the slow light filtering performance of the zero contrast grating due to the influence of the etching depth on the resonance mode constrained within the waveguide layer.However

the grating period mainly affects the phase matching between the incident light and the waveguide mode.Different grating periods can be used to select the different slow light filtering channels in the C band.In addition

the mode splitting effect of the oblique incidence condition is studied

and it is noted that the excitation of the non-degenerate resonant waveguide under the oblique incident condition leads to smaller the peak transmission an larger group refraction index.This research provides a new solution for the design of slow light devices.