Sensing μm-scale vibrations in the Hz range within a THz communication system

Area of Science:

• Physics
• Electrical Engineering
• Signal Processing

Background:

• Integrated Sensing and Communication (ISAC) systems offer potential for simultaneous data transmission and environmental monitoring.
• Terahertz (THz) frequencies present opportunities for high bandwidth but face challenges in signal propagation and sensing sensitivity.
• Traditional sensing methods often rely on backscattered signals, which suffer from significant path loss and reduced receiver sensitivity.

Purpose of the Study:

• To demonstrate a THz-band ISAC system capable of detecting micrometer-scale vibrations in real-time.
• To leverage an optical frequency comb for enhanced THz signal generation and vibration sensitivity.
• To achieve parallel sensing and high-capacity communication using the same hardware and transmitted signal.

Main Methods:

• Generation of THz signals using an optical frequency comb to suppress carrier frequency noise and enhance vibration sensitivity.
• Utilization of the forward transmitted signal for direct detection by the receiver, overcoming path loss challenges.
• Implementation of a 220-330 GHz ISAC system transmitting 2x112.8 Gb/s 16QAM signals for simultaneous communication and sensing.

Main Results:

• Successful detection of micrometer-scale (±3.8 μm) vibrations at 45 Hz.
• Demonstration of anomaly detection in a 9-meter tower scenario by identifying abnormal frequency shifts in vibration.
• Validation of the system's capability to perform sensing in parallel with high-capacity data transmission.

Conclusions:

• The developed THz-band ISAC system effectively detects subtle vibrations using the forward transmitted signal.
• The use of an optical frequency comb significantly improves sensing sensitivity in the THz band.
• This approach enables efficient, simultaneous sensing and communication within a single system, paving the way for advanced applications.