Optical Frequency Standard For Optical Fiber Communication Based On The Rb 5s->5d Two-Photon Transition

We report an optical frequency standard based on the 5s-->5d two-photon transition in Rb atoms. The frequency of a lambda=778 nm diode laser was locked to the two-photon transition. Second-harmonic generation and an optical phase-locked loop were used to transfer the Frequency stability to lambda=1.556 mu m for use in optical fiber communication applications. (C) 1997 Optical Society of America.