New directions for optical frequency division: Soliton microcombs and electro-optical-modulation

Optical frequency division based on mode-locked laser frequency combs makes possible the coherent transfer of frequency stability from optical systems to electronics. It has enabled a revolution in time keeping and frequency metrology. In this paper we describe progress on new methods for frequency comb generation including whispering-gallery-based microcombs and electro-optical comb generation. Demonstration of optical frequency division to produce stable microwaves using these new approaches will be discussed.