High-quality ultra-low-noise microwave signals using only a single laser generated from tiny photonic chip

https://phys.org/news/2024-03-high-quality-microwave-generated-tiny.html

"2 silicon nitride microresonators photonically coupled, single-frequency laser pumping both... 1 creates optical parametric oscillator converting input wave into 2 output THz, 1 higher, 1 lower, enabling noise of frequency difference 1,000sX less than of input laser... 2nd microresonator generates optical frequency comb with microwave spacing... both synchronized resulting in optical frequency division without electronics... as small as 1mm2 generating 16-GHz communication, atomic clocks, autonomous vehicles"