250 Gb/s All-Optical XNOR Logic Using a Single QD-SOA-MZI: Demonstration and Comprehensive Performance Analysis

Area of Science:

• Optoelectronics and Photonics
• Optical Communications
• Nonlinear Optics

Background:

• Optical networks demand faster data rates, necessitating all-optical logic gates to overcome electro-optic conversion limitations.
• Quantum-dot semiconductor optical amplifiers (QD-SOAs) offer ultrafast carrier dynamics and high nonlinearity, making them suitable for high-speed optical processing.

Purpose of the Study:

• To numerically simulate and analyze the performance of an all-optical XNOR logic gate.
• To investigate the operational envelope and optimize critical parameters for a QD-SOA-MZI based gate.
• To confirm the potential of this device for ultra-high-speed optical communication systems.

Main Methods:

• Numerical simulation of an all-optical XNOR logic gate implemented with a single QD-SOA in a Mach-Zehnder interferometer (MZI).
• Performance analysis based on Quality Factor (QF) and theoretical bit-error rate (BER).
• Systematic investigation of parameter dependence including data rate, pulse energy, probe power, injection current density, and noise tolerance.

Main Results:

• The QD-SOA-MZI gate operates at 250 Gb/s with a QF of 26.30 (BER < 10^-9).
• The gate maintains QF > 6 up to 700 Gb/s (QF = 10.47), demonstrating robust high-speed capability.
• Optimal performance is achieved at specific pulse energy (0.20 pJ), probe power (0.40 mW), and injection current density (4 kA/cm²), with defined noise tolerances.

Conclusions:

• The QD-SOA-MZI all-optical XNOR gate shows significant potential for ultra-high-speed optical signal processing.
• Parameter optimization is crucial for maximizing performance and ensuring signal integrity in practical applications.
• This technology offers a compact and efficient solution for future optical communication networks.