Sukhorukov, Andrey A.Ha, SangwooDossou, Kokou B.Botten, Lindsay C.Lavrinenko, Andrei V.Chigrin, Dmitry N.Kivshar, Yuri S.2025-12-312025-12-3197808194707990277-786XORCID:/0000-0002-3410-812X/work/163397987https://hdl.handle.net/1885/733797435We propose a general approach to the design of directional couplers in photonic-crystals operating in the slowlight regime. We predict, based on a general symmetry analysis, that robust switching of slow-light pulses is possible between antisymmetrically coupled photonic crystal waveguides. We demonstrate, through numerical Bloch mode frequency-domain and finite-difference time-domain (FDTD) simulations that, for all pulses with strongly reduced group velocities at the photonic band-gap edge, complete switching occurs at a fixed coupling length of just a few unit cells of the photonic crystal.enDirectional couplerPhotonic crystalSlow light200810.1117/12.77223240749087254