Photonic sampling of microwave signals with adjustable sampling frequencies using an optical frequency comb

Area of Science:

• Photonics
• Optical Communications
• Signal Processing

Background:

• Traditional sampling methods face limitations in achieving high frequencies and flexibility.
• Optical frequency combs offer precise and tunable light sources for advanced applications.

Purpose of the Study:

• To propose and demonstrate a novel photonic sampling technique.
• To achieve flexible sampling frequencies using an agile optical frequency comb generator.
• To enable high-speed sampling and demodulation of complex signals.

Main Methods:

• Utilizing an agile optical frequency comb generator to create sampling pulses.
• Carving multiple comb lines into sampling pulses.
• Time-dispersing pulses in a single-mode optical fiber.
• Electronically adjusting comb line spacing and selecting comb lines.

Main Results:

• Demonstrated successful sampling and demodulation of Quadrature Amplitude Modulation (QAM) signals.
• Achieved carrier frequencies up to 17 GHz.
• Reached sampling rates as high as 50 Giga Samples per second (GSa/s).
• Measured a minimum Error Vector Magnitude (EVM) of 1.5% at 3 GHz.
• Recorded a maximum Effective Number of Bits (ENOB) of 4.4 at 2.1 GHz.

Conclusions:

• The proposed photonic sampling technique offers a flexible and high-performance solution for modern signal processing.
• This method paves the way for advancements in high-frequency optical signal sampling and analysis.