Reconfigurable 2D optical tapped-delay-line to perform correlation on images

Area of Science:

• Optoelectronics
• Signal Processing
• Optical Communications

Background:

• Quadrature-phase-shift-keying (QPSK) is a digital modulation technique used in high-speed optical communications.
• Optical tapped-delay-line (OTDL) architectures are employed for signal processing tasks, including correlation.
• Real-time correlation of optical signals is crucial for various applications, such as pattern recognition and data processing.

Purpose of the Study:

• To demonstrate a reconfigurable 2D optical tapped-delay-line (OTDL) correlator.
• To achieve correlation of 20 Gbaud quadrature-phase-shift-keying (QPSK) data.
• To evaluate the performance of the 2D correlator in terms of error vector magnitude (EVM) and pattern recognition capabilities.

Main Methods:

• Implementation of two independent OTDLs for row-wise correlation (inner sum).
• Coherent multiplexing of correlated rows for column-wise correlation (outer sum) to achieve 2D correlation.
• Testing the system by searching for 2x2 patterns within a 31x31 image.

Main Results:

• A 2D optical correlator was successfully demonstrated.
• The system achieved an average error vector magnitude (EVM) of approximately 7.8%.
• The correlator successfully recognized target 2x2 patterns within the 31x31 image.

Conclusions:

• The reconfigurable 2D OTDL is an effective architecture for correlating high-speed QPSK data.
• The developed 2D correlator shows promise for applications in optical signal processing and image recognition.
• The system's performance metrics (EVM) indicate its viability for practical implementation.