Bispectral magnitude and phase recovery using a wide bandwidth acousto-optic processor

Area of Science:

• Signal Processing
• Optical Engineering
• Applied Physics

Background:

• Bispectrum analysis is crucial for characterizing nonlinearities in RF signals.
• Traditional methods for bispectrum computation can be computationally intensive and limited in bandwidth.
• Developing efficient processors for wide bandwidth RF signals is an ongoing challenge.

Purpose of the Study:

• To develop and validate a hybrid optical-digital processor for computing bispectrum magnitude and phase.
• To assess the processor's performance with wide bandwidth radio frequency (RF) signals.
• To demonstrate the recovery of magnitude and phase information for quadratically related signals.

Main Methods:

• A modified Mach-Zehnder interferometer with acousto-optic modulators forms the optical core.
• Digital processing, including filtering and Hilbert transformation, isolates and computes the bispectrum.
• The processor was tested using various RF test signals with different bandwidths.

Main Results:

• The hybrid processor successfully computed both magnitude and phase of the bispectrum.
• Effective processing of wide bandwidth (10 MHz to 1 GHz) RF signals was demonstrated.
• Accurate recovery of bispectrum information for quadratically related signals was confirmed through test results.

Conclusions:

• The developed hybrid optical-digital processor offers an efficient solution for bispectrum analysis of wide bandwidth RF signals.
• This technology has potential applications in areas requiring detailed nonlinear signal characterization.
• The combination of optical and digital techniques provides a powerful approach for advanced signal processing.