Abstract
With the explosive growth of global wireless data traffic, the Terahertz band (0.3–10 THz) is promising for ultrafast wireless communications, due to the enormous available bandwidth [1]. Photonic generation of THz carriers displays extremely large tunable range and modulation bandwidth, making it nearly ideal for THz communications. However, the current photonics-based THz carrier generators are based on discrete bulky components [2] with high cost and energy consumption, which hinder them from practical applications. Here, we present an injection-locked heterodyne source based on generic foundry-fabricated photonic integrated circuits (PIC) attached to a photo-mixing uni-travelling carrier photodiode (UTC-PD), generating high-purity THz carriers for high-speed and long-distance wireless communication. The generated THz carrier can span from 0 to 1.4 THz, determined by the tunable wavelength spacing between the two distributed feedback (DFB) modes within the range 0-10.7 nm. We show that a generated 0.4 THz carrier transmits a record-high single-channel net rate of 131 Gbit/s over 10.7 m of wireless distance with only − 24 dBm emitted THz power, by employing 16-QAM-OFDM modulation and a nonlinear equalization technique. To the best of our knowledge, this is the highest data rate for a single-channel THz wireless transmission and requires the lowest THz power/bitrate/distance. The scheme of the monolithic dual-DFB PIC based THz generation shows a great potential for fully integrated, cost-effective and energy-efficient THz transmitters.
Theoretical and experimental investigation of compatible SSB modulation for single channel long-distance optical OFDM transmission