Demonstration of a Timescale Based on a Stable Optical Carrier

We demonstrate a time scale based on a phase stable optical carrier that accumulates an estimated time error of 48\pm94ps over 34 days of operation. This all-optical time scale is formed with a cryogenic silicon cavity exhibiting improved long-term stability and an accurate ^{87}r lattice clock. We show that this new time scale architecture outperforms existing microwave time scales, even when they are steered to optical frequency...