Terahertz wave generation using a soliton microcomb

Shuangyou Zhang, Jonathan M. Silver, Xiaobang Shang, Leonardo Del Bino, Nick M. Ridler, Pascal Del’Haye*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)
74 Downloads (Pure)


The Terahertz or millimeter wave frequency band (300 GHz - 3 THz) is spectrally located between microwaves and infrared light and has attracted significant interest for applications in broadband wireless communications, space-borne radiometers for Earth remote sensing, astrophysics, and imaging. In particular optically generated THz waves are of high interest for low-noise signal generation. Here, we propose and demonstrate stabilized terahertz wave generation using a microresonator-based frequency comb (microcomb). A unitravelling-carrier photodiode (UTC-PD) converts low-noise optical soliton pulses from the microcomb to a terahertz wave at the soliton’s repetition rate (331 GHz). With a free-running microcomb, the Allan deviation of the Terahertz signal is 4.5×10−9 at 1 s measurement time with a phase noise of -72 dBc/Hz (-118 dBc/Hz) at 10 kHz (10 MHz) offset frequency. By locking the repetition rate to an in-house hydrogen maser, in-loop fractional frequency stabilities of 9.6×10−15 and 1.9×10−17 are obtained at averaging times of 1 s and 2000 s respectively, indicating that the stability of the generated THz wave is limited by the maser reference signal. Moreover, the terahertz signal is successfully used to perform a proof-of-principle demonstration of terahertz imaging of peanuts. Combining the monolithically integrated UTC-PD with an on-chip microcomb, the demonstrated technique could provide a route towards highly stable continuous terahertz wave generation in chip-scale packages for out-of-the-lab applications. In particular, such systems would be useful as compact tools for high-capacity wireless communication, spectroscopy, imaging, remote sensing, and astrophysical applications.

Original languageEnglish
Pages (from-to)35257-35266
Number of pages10
JournalOptics Express
Issue number24
Early online date18 Nov 2019
Publication statusPublished - 25 Nov 2019

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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