Open AccessUltra-low phase noise microwave generation with a free-running monolithic femtosecond laser
Author(s) -
Manoj Kalubovilage,
Mamoru Endo,
Thomas R. Schibli
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.399425
Subject(s) - phase noise , dbc , noise floor , optics , relative intensity noise , microwave , materials science , noise (video) , optoelectronics , laser , photonics , femtosecond , noise generator , physics , noise reduction , noise measurement , noise figure , semiconductor laser theory , acoustics , computer science , amplifier , cmos , quantum mechanics , artificial intelligence , image (mathematics)
Phase noise performance of photonic microwave systems, such as optical frequency division (OFD), can surpass state-of-the-art electronic oscillators by several orders of magnitude. However, high-finesse cavities and active stabilization requirements in OFD systems make them complicated and potentially unfit for field deployment. Ultra-low noise mode-locked monolithic lasers offer a viable alternative for a compact and simple photonic microwave system. Here we present a free-running monolithic laser-based 8 GHz microwave generation with ultra-low phase noise performance comparable to laboratory OFD systems. The measured noise performance reached -130 dBc/Hz at 100 Hz, - 150 dBc/Hz at 1 kHz, and -167 dBc/Hz at 10 kHz offsets from the 8-GHz carrier. We also report a sub-Poissonian noise floor of -179 dBc/Hz above 30 kHz (timing noise floor of 32 zs Hz -1/2 ), which is ∼12 dB below the noise floor of time-invariant shot noise. In addition to the low phase noise, the system is compact, with a power consumption of less than 9 W, and offers excellent potential for mobile or space-borne applications.