Phase noise reduction of an RF oscillator by photonic-based highly sensitive phase noise analyzer

Abstract

Low phase noise micro — mm waves are critical building blocks for future wireless communications and radar. Micro — mm waves generated by optical frequency combs via optical frequency division can have extremely low phase noise [1], but producible RF carrier frequencies are essentially limited to harmonics of the comb repetition frequency. Actively suppressing phase noise of RF oscillators is a more universal way to generate low noise arbitrary RF carrier frequencies [2, 3]. For this, electro-optic comb (EO comb) based active phase noise suppression of RF oscillators is a powerful method, compatible with referencing to micro cavities [2] and optical frequency combs [3]. In this report, we propose and demonstrate an alternative approach for active phase noise suppression by referencing to a long fiber delay, based on highly sensitive phase noise measurements as enabled via a two wavelength, delayed self-heterodyne interferometer [4].