Tunable X-band opto-electronic synthesizer with ultralow phase noise

Published

March 29, 2024

Author(s)

Igor Kudelin, Pedram Shirmohammadi, William Groman, Samin Hanifi, Megan Kelleher, Dahyeon Lee, Takuma Nakamura, Charles McLemore, Steven Bowers, Franklyn Quinlan, Scott Diddams

Abstract

Microwave signals with low phase noise in the X-band (8-12 GHz) are essential for widespread technologies and important scientific developments. Photonic techniques, such as optical frequency division (OFD), leverage the high spectral purity of low-noise lasers and frequency combs to generate such microwaves. However, conventional photonic techniques have suffered from a lack of frequency tunability as well as substantial size, weight, and power (SWaP) that largely limits their application to laboratory settings. In this work we present a hybrid opto-electronic approach that combines a simplified two-point OFD scheme with direct digital synthesis (DDS) to produce tunable low phase noise microwaves across the entire X-band. This results in exceptional phase noise at 10 GHz of -156 dBc/Hz at 10 kHz offset and fractional frequency instability of 1×10−13 at 0.1 s. Spot tuning away from this point by ±500 MHz, ±1 GHz, and ±2 GHz, yields phase noise at 10 kHz offset of -150 dBc/Hz, -146 dBc/Hz, and -140 dBc/Hz, respectively. Our work illustrates a powerful synthesis technique that shares the combined benefits of low timing noise provided by photonics and the frequency agility of established digital synthesis.

Citation

Nature Electronics

Pub Type

Journals

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Citation

Kudelin, I. , Shirmohammadi, P. , Groman, W. , Hanifi, S. , Kelleher, M. , Lee, D. , Nakamura, T. , McLemore, C. , Bowers, S. , Quinlan, F. and Diddams, S. (2024), Tunable X-band opto-electronic synthesizer with ultralow phase noise, Nature Electronics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957717 (Accessed October 14, 2025)