Tunable terahertz signal generation based on an on-chip wideband electro-optic frequency comb

We demonstrate a low-noise, tunable terahertz (THz) source based on an electro-optic frequency comb. In this approach, the lithium niobate electro-optic comb serves as the master laser, and two distributed feedback (DFB) lasers serve as slave lasers. Through master-slave injection locking, selected coherent comb lines are preserved and amplified, and the resulting THz signal is generated via down-conversion. The THz signals are generated by a high-bandwidth photodiode (PD) and received by a harmonic mixer (HM), yielding a measured single-sideband phase noise of -89.53 dBc/Hz at a 100 kHz offset for the 150 GHz signal, which allows the generation of THz signals from 135 GHz to 210 GHz. This work paves the way for fully integrated THz signal generation and has significant potential for THz research and applications.