Design and Simulation of a Fast All-Optical Modulator Based on Photonic Crystal Using Ring Resonators

In the present paper, the design and simulation of a fast all-optical modulator based on the photonic crystal structure have been presented and its performance characteristics have been investigated. The photonic crystal of this structure has been made of 50 × 27 dielectric rods in the air bed with a hexagonal lattice. To benefit from silicon technology and the simplicity of the structure, dielectric rods have been made of silicon with a refractive index of 3.46. The value of lattice constant (a) has been considered to be 525 nm and the radius of the dielectric rods (R) has been equal to about 111 nm. In this modulator, the carrier beam is controlled by the input signal beam. The structure includes a two-dimensional ring resonator located between two central waveguides. To analyze this structure, two numerical methods of plane-wave expansion (PWE) and finite-difference time-domain (FDTD) have been used. In this structure, the extinction ratio, insertion loss, and response time have been equal to 19.81 dB, −0.76 dB, and 1.4 ps, respectively. Due to the very low insertion loss and very fast response time, this structure can be considered as a very fast and extremely optimal optical modulator. This structure has had a size of about 309 μm2.