We describe and demonstrate a multiloop technique for single-mode selection
in an optoelectronic oscillator (OEO). We present experimental results of
a dual loop OEO, free running at 10 GHz, that has the lowest phase noise (-
140 dBc/Hz at 10 kHz from carrier) of all free-running room-temperature osc
illators to date. Finally, we demonstrate the first fiber-optic implementat
ion of the carrier suppression technique to further reduce the close-toe ca
rrier phase noise of the oscillator by at least 20 dB.