Observation of Fundamental Charge Noise in Electro-Optic Photonics Integrated Circuits

We observed a novel 1/f-type frequency noise in Lithium Niobate and Lithium Tantalate microresonators, distinct from thermorefractive noise and originating from thermodynamic charge fluctuations, setting the linewidth limits for integrated lasers. A charge-noise-limited laser with sub-hundred-hertz linewidth is demonstrated.