Femtosecond atmospheric frequency transfer using diode laser with electronic phase compensation

Abstract

We demonstrated an atmospheric radio-frequency transfer over a 50 m outdoor free-space link using a compact diode laser with an electronic phase compensation technique. With transferring a 1 GHz microwave signal in 5000 seconds, the total root-mean-square (RMS) timing fluctuation was measured to be about 560 fs, with fractional frequency instability on the order of 4 × 10−13 at 1 s, and order of 4 × 10−16 at 1000 s. This atmospheric frequency transfer scheme can be used to disseminate a commercial Rb or Cs clock via a free-space transmission link.