Wide-bandwidth frequency locking of a 1083-nm extended-cavity DBR diode laser to a high-finesse Fabry-Pérot resonator

We report frequency locking of a 1083-nm DBR diode laser on a high-finesse Fabry-Perot cavity (F ~ 2800). We used the Pound-Drever FM locking scheme at a modulation rate of 5MHz. A lock bandwidth of about 1MHz is obtained by using a three-path servo loop. The laser linewidth is narrowed to ~ 5 kHz. The root Allan variance sigma(tau) of the laser frequency with respect to the cavity reaches a minimum of 4+/-1Hz at tau=10 s.