Electrical Tuning of Optical Delay in Graphene-Based Photonic Crystal Waveguide

An electrically controlled graphene-based line-defect photonic crystal waveguide (PCW) is proposed for tuning the group delay. We found that the introduction of few-layer graphene into the PCW can slow down the guided light. Two designs are proposed: one with the graphene on the core region (line defect) and the other with the graphene on the cladding region. A group delay tuning of 29 ps is reported with both the designs on varying the applied voltage (on graphene) from 1 to 4 V. The presence of graphene not only provides the way to electrically tune the delay (with low power) but also enhances the group delay to some extent. The proposed PCW with graphene can have potential in realizing low-power electrically controllable on-chip delay lines.