All-optical tunable slow light achievement in photonic crystal coupled-cavity waveguides

In this paper, a tunable low power slow light photonic crystal device with a silicon-on-insulator platform is proposed based on the combination of an asymmetric defects coupled-cavity waveguide and the electromagnetically induced transparency (EIT) phenomenon. Modulating the refractive index of special regions in the suggested structure by the EIT phenomenon leads to a relatively wideband slow light device with adjustable group index in the same structure. Using this feature, a small and compact delay line is introduced that has many applications in optical telecommunications, especially in buffers. The numerical calculations show that the group index of 80-98 over the slow light bandwidth from 3.2 to 2.6 nm is achievable for the central wavelength of 1546-1555 nm, respectively. The device malfunction, due to fabrication errors, is modeled, and the tunable characteristics of the proposed structure are verified.