Simultaneous generation of a stepped-frequency signal and microwave frequency comb based on a dual recirculating...

Area of Science:

• Photonics
• Signal Processing
• Microwave Engineering

Background:

• Generating complex radio frequency (RF) signals like stepped-frequency (SF) signals and microwave frequency combs (MFCs) is crucial for modern communication and radar systems.
• Existing methods often face limitations in flexibility and simultaneous generation of these signal types.

Purpose of the Study:

• To propose and demonstrate a novel scheme for the simultaneous generation of SF signals and MFCs.
• To leverage a dual recirculating frequency shift loop (RFSL) architecture for enhanced signal generation capabilities.

Main Methods:

• A photoelectric RFSL (loop 1) utilizing a dual-parallel Mach-Zehnder modulator (DPMZM) generates the SF signal.
• An optical RFSL (loop 2) driven by the SF signal produces an optical frequency comb (OFC).
• Self-heterodyne and heterodyne detection convert the OFC into various MFCs with tunable parameters.

Main Results:

• Simulation successfully generated an SF signal with frequencies from 6 to 10 GHz (1 GHz increment).
• Generated MFCs exhibited low power fluctuations (<3 dB) and high signal-to-noise ratios (>20 dB for self-heterodyne, >34 dB for heterodyne).
• Parameters of SF signals and MFCs were shown to be flexibly tunable by adjusting bandwidth and input signal frequencies.

Conclusions:

• The proposed dual RFSL scheme effectively achieves simultaneous generation of SF signals and MFCs.
• The system demonstrates high performance in terms of signal quality and parameter tunability.
• This approach offers a flexible and efficient method for generating advanced RF signal types.