Design of All-Optical D Flip Flop Memory Unit Based on Photonic Crystal

Area of Science:

• Photonics
• Optical Computing
• Materials Science

Background:

• All-optical computing requires efficient logic gates.
• Photonic crystals offer unique light manipulation properties.
• Fabrication challenges exist for certain photonic crystal designs.

Purpose of the Study:

• To propose and simulate a novel all-optical D Flip Flop (D-FF).
• To utilize a silicon/silica photonic crystal structure for improved fabrication.
• To assess the D-FF's performance for integration into optical arithmetic logic units (ALUs).

Main Methods:

• Design and simulation of optical waveguides and a quasi-square ring resonator in a 2D square lattice photonic crystal.
• Utilized plane-wave expansion (PWE) and finite-difference time-domain (FDTD) simulation methodologies.
• Optimized the design for operation at 1550 nm within the C-band spectrum.

Main Results:

• The designed photonic crystal structure successfully guides light, demonstrating D-FF functionality.
• Achieved a clear distinction between logic states '1' and '0' for robust decision-making.
• Reported a contrast ratio (CR) of 4.77 dB, stabilization time of 0.66 psec, and a compact footprint of 21 μm × 12 μm.

Conclusions:

• The proposed all-optical D-FF is a promising logic block for digital optical circuits and ALUs.
• The silicon/silica substrate facilitates practical fabrication compared to air-substrate designs.
• The design offers high performance with minimal logic errors for future optical computing applications.