Offset phase locking of Er : Yb : Glass laser eigenstates for RF photonicsapplications

An optical source of microwaves with very low phase noise for communication s and radar systems is realized and tested. It is obtained by dual-frequenc y operation of a diode pumped Er:Yb:Glass laser. An electrooptic crystal in serted inside the resonator permits both to tune the frequency difference b etween orthogonally polarized eigenstates, and to turn the laser into a vol tage controlled oscillator. An optical phase-locked loop is then implemente d in the GHz range, resulting in a measured instrument limited 3 dB-linewid th of 10 Hz. The phase noise is shown to be -100 dBc/Hz at 10-kHz offset.