High-SFDR 100.8km ROF link with optical homodyne detection and genetic-algorithm-assisted digital demodulation

Area of Science:

• Optoelectronics
• Radio-Frequency Engineering
• Signal Processing

Background:

• Radio-over-fiber (ROF) links are crucial for linear analog radio-frequency (RF) signal transmission.
• Increasing demands exist for long-distance RF signal transmission in radar and broadcast systems.
• Existing ROF links face challenges in maintaining performance over long distances and wide temperature variations.

Purpose of the Study:

• To propose and experimentally investigate a high spurious-free-dynamic-range (SFDR) analog coherent ROF link.
• To enable reliable long-distance transmission of analog RF signals (500 kHz to 100 MHz).
• To assess link performance under wide temperature fluctuations (-40°C to 70°C).

Main Methods:

• Utilized optical homodyne detection for coherent signal reception.
• Implemented genetic-algorithm-assisted digital demodulation for signal processing.
• Employed a 100.8-km single-mode fiber (SMF) for signal transmission.

Main Results:

• Achieved a shot-noise-limited SFDR greater than 122 dB·Hz^2/3.
• Successfully transmitted RF signals across a broad frequency range (500 kHz to 100 MHz).
• Demonstrated robust performance under a wide temperature range (-40°C to 70°C).

Conclusions:

• The proposed analog coherent ROF link offers high SFDR for demanding RF transmission applications.
• The system is suitable for long-distance, wide-temperature environments.
• Optical homodyne detection and genetic-algorithm-assisted demodulation are effective for high-performance ROF links.