Increasing the bandwidth of slow light in fishbone-like grating waveguides

Slow light, a technology to control the optical signal by reducing the group velocity, has been widely studied to obtain enhanced nonlinearities and increased phase shifts owing to its promoting of the light-matter interaction ability. In this work, a wideband slow light is achieved in a simple one-dimensional fishbone grating waveguide. A flat band indicating slow light with a group index of 13 and bandwidth over 10 nm is obtained by the plane wave expansion calculation, and the corresponding experimental results agree well with the theoretical prediction. A step taper is designed to compensate the coupling loss. The proposed fishbone grating waveguide is a good candidate for wideband slow light devices in light communication. (C) 2019 Chinese Laser Press