Simultaneous Transfer of Stabilized Optical and Microwave Frequencies Over Fiber

We demonstrate simultaneous stabilization of optical and microwave signals on an optical-fiber link by independently stabilizing two optical signals that are separated by a nominated microwave frequency. This system can be implemented on conventional stabilized optical frequency transfer networks without degrading the stability of the optical signal, increasing the scope of applications of existing and future large-scale frequency transfer networks. For a 30 km optical-fiber link, we demonstrate a 193 THz optical carrier transfer absolute frequency stability of 4.9 ×10 -5 Hz at 10 3 s, and a 10.02 GHz microwave signal transfer absolute frequency stability of 1.3 ×10 -4 Hz at 10 3 s.