All-optical half adder based on cross structures in two-dimensional photonic crystals

Area of Science:

• Photonics
• Optical Computing
• Materials Science

Background:

• All-optical computing offers potential for higher speeds than electronic systems.
• Photonic crystals provide a versatile platform for manipulating light.
• Implementing logic gates optically is crucial for integrated optical circuits.

Purpose of the Study:

• To propose and numerically demonstrate an all-optical half adder.
• To utilize two distinct cross structures in 2D photonic crystals for logic operations.
• To achieve efficient integration of AND and XOR logic gates.

Main Methods:

• Design of two cross structures in 2D photonic crystals.
• One structure incorporates nonlinear materials for AND gate functionality.
• The other structure uses linear materials for XOR gate functionality.
• Numerical simulation using the Finite-Difference Time-Domain (FDTD) method.

Main Results:

• Successful numerical demonstration of the all-optical half adder.
• Achieved an optimal operating speed of 0.91 Tbps (excluding nonlinear material response time).
• Obtained a minimum ON to OFF logic-level contrast ratio of 16 dB.
• Determined a minimum power consumption of 436 mW.

Conclusions:

• The proposed all-optical half adder functions as expected.
• The design shows potential for constructing all-optical integrated digital computing circuits.
• This work contributes to the advancement of high-speed optical information processing.