Optics to microwave low phase noise frequency division : Synchronization with stability below 100 attoseconds

We present our results on optical to microwave frequency division by fiber-based optical frequency combs. The phase noise added by the division process is characterized and several noise reduction strategies are demonstrated. We reach −123dBc/Hz at 1Hz from a 11.55GHz carrier and about −130dBc/Hz above 200Hz Fourier frequency. The fractional frequency stability scales as 1.1×10
⁻¹⁶
τ
⁻¹
T where t is the averaging time in seconds. We demonstrate optics to microwave synchronization stability below 100 attoseconds from 1s to 1000s timescale