NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Broadband Optoelectronic Mixer for Terahertz Frequency-Comb Measurements
Published
Author(s)
Jizhao Zang, Jesse Morgan, Andreas Beling, Scott Papp
Abstract
We demonstrate ultra-broadband optoelectronic mixing of frequency combs that provides phase-coherent detection of a repetition frequency up to 500 GHz, using a high-speed modified uni-traveling carrier (MUTC) photodiode. Nonlinear photo-electron effects in the photodiode itself enable harmonic generation and down-mixing process of combs with widely different repetition frequency. Specifically, we generate two, 25 GHz frequency combs and use an optical filter to explore coherent down-mixing to baseband of comb spectral components across microwave, millimeter wave, and THz frequencies. The exceptional noise performance of the optoelectronic mixer enables the phase-coherent measurement of millimeter and THz frequency combs with an Allan deviation of 10^-13/τ for a measurement time of τ. We further investigate the dependence of conversion loss on the reverse bias voltage and photocurrent. The experimental results indicate that we can minimize the conversion loss by operating the photodiode at an optimal voltage and maximum available photocurrent. Our work provides a solution for millimeter and THz frequency comb measurements and facilities fully stabilized frequency combs with microresonators.
Zang, J.
, Morgan, J.
, Beling, A.
and Papp, S.
(2025),
Broadband Optoelectronic Mixer for Terahertz Frequency-Comb Measurements, Optics Letters, [online], https://doi.org/10.1364/OL.557366, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958964
(Accessed October 9, 2025)