A phase-locked frequency divide-by-3 optical parametric oscillator

Accurate phase-locked 3:1 division of an optical frequency was achieved, by using a continuous-wave (cw) doubly resonant optical parametric oscillator. A fractional frequency stability of 2/spl times/10/sup -17/ of the division process has been achieved for 100 s integration time. The technique developed in this work can be generalized to the accurate phase and frequency control of any cw optical parametric oscillators.