On-Off-Keying Data Transmission Achieved with Terahertz-to-Optical Carrier Conversion Using Optical Comb and Electro-Optic Polymer Modulator

As the development of next-generation mobile communications (6G) progresses, terahertz (THz) waves are being actively explored as a potential wireless carrier. One of the critical challenges in THz communications is the detection of THz waves. However, existing THz detectors suffer from significant drawbacks: they are bulky, expensive, fragile, and lack versatility, limiting their practicality for widespread deployment. To address these challenges, a promising approach is the THz-to-optical carrier conversion [1]. This technique enables the transmission information of a THz carrier wave to be transferred to optical carrier waves using an electro-optic polymer (EOP) modulator [2], thereby detecting the THz transmission information as an optical signal. This method leverages dual-wavelength optical carriers derived from an optical comb as references to achieve high precision and stability. In our previous research, we successfully demonstrated the detection of an unmodulated THz carrier wave at a frequency of 100 GHz using this approach. In this study, we extend this method to detect an On-Off-Keying (OOK) modulated signal in the same 100 GHz band. Furthermore, we evaluate the transmission quality of the detected signal, providing insights into its feasibility for practical 6G communication systems.