Equivalent photonic switch for microwave frequency shift keying signal generation

Area of Science:

• Photonics and Optical Communications
• Microwave Engineering
• Signal Generation

Background:

• Development of efficient and tunable microwave signal generators is crucial for modern communication systems.
• Photonic approaches offer advantages in bandwidth and signal manipulation for microwave signal generation.
• Existing methods for frequency shift keying (FSK) signal generation can be complex or lack tunability.

Purpose of the Study:

• To propose and experimentally demonstrate a novel photonic microwave frequency shift keying (FSK) signal generator.
• To achieve flexible frequency intervals and high tunability in generated microwave FSK signals.
• To evaluate the performance of the proposed generator, including stability, loss, and error rates.

Main Methods:

• An equivalent photonic switch (EPS) was constructed using a polarization-multiplexing dual-drive Mach-Zehnder modulator (PM-DMZM).
• Control of data sequences and radio frequency (RF) signals applied to the PM-DMZM enabled microwave FSK signal generation.
• Experimental validation involved generating signals at specific data rates and frequencies, followed by transmission over single-mode fiber.

Main Results:

• Successfully generated 2 Gb/s microwave FSK signals at 5/14 GHz and 1 Gb/s at 6/20 GHz.
• Demonstrated successful transmission of generated signals over 5 km of single-mode fiber.
• Achieved a low required received optical power of -14.48 dBm at the 7% forward error correction threshold.

Conclusions:

• The proposed photonic FSK signal generator, based on an EPS, offers a simple structure with low loss and good stability.
• The system exhibits excellent frequency tunability and can be reconfigured for amplitude and phase shift keying generation.
• The experimental results confirm the feasibility and high performance of the photonic approach for generating high-quality microwave FSK signals.