Photonic approach to microwave frequency measurement with digital circular-code results

Area of Science:

• Photonics
• Microwave Engineering
• Signal Processing

Background:

• Accurate microwave frequency measurement is crucial for modern communication systems.
• Existing methods often require complex electronic components or lack simultaneous analog-to-digital conversion.

Purpose of the Study:

• To propose and demonstrate a photonic approach for digital microwave frequency measurement.
• To achieve simultaneous frequency-to-amplitude conversion and analog-to-digital conversion.

Main Methods:

• Designing N photonic phase-shifted filters with specific phase increments.
• Utilizing these filters to process a single optical sideband from a single sideband suppressed-carrier (SSB-SC) modulated microwave signal.
• Implementing power detection and decision operations for N-bit circular code generation.

Main Results:

• A proof-of-concept experiment successfully verified the proposed photonic approach.
• A 5-bit circular code was generated, enabling microwave frequency indication up to 40 GHz.
• The method demonstrated simultaneous frequency-to-amplitude and analog-to-digital conversion.

Conclusions:

• The proposed photonic method offers a novel way to measure microwave frequency with digital outputs.
• This technique integrates frequency measurement and analog-to-digital conversion, simplifying system design.
• The demonstrated approach shows potential for high-frequency applications.