Hybrid optoelectronic I/Q integrated down-conversion system for terahertz wireless-fiber communications.

Area of Science:

• Optoelectronics
• Optical Communications
• Wireless Communications

Background:

• Fiber-wireless systems integrate optical fiber and wireless technologies for high-capacity communication.
• Efficient electro-optic receivers are crucial for millimeter-wave (mmWave) and terahertz (THz) fiber-wireless systems.
• Traditional receivers face challenges with conjugate spectra and image interference during signal down-conversion.

Purpose of the Study:

• To introduce a novel hybrid electro-optic receiver design for direct complex intermediate frequency (IF) signal conversion.
• To overcome limitations of traditional real-valued IF processing and balanced mixers.
• To enable optical single-sideband modulation without optical filtering and eliminate image interference.

Main Methods:

• Directly connecting an electrical I/Q mixer with an optical I/Q modulator.
• Utilizing the inherent I/Q orthogonality for preserving signal integrity.
• Implementing a hybrid optoelectronic communication system architecture.

Main Results:

• Demonstrated direct electro-optic conversion of complex IF signals.
• Achieved optical single-sideband modulation without optical filtering.
• Successfully transmitted 16 Gbaud Quadrature Phase Shift Keying (QPSK) signals error-free over a 2-m wireless link and a 5-km single-mode fiber at 142.8 GHz.

Conclusions:

• The proposed hybrid electro-optic receiver effectively addresses image interference issues in fiber-wireless systems.
• This design facilitates high-frequency signal transmission with enhanced performance.
• The successful demonstration validates the potential of this innovative optoelectronic communication system.