Decentralized frequency stabilization scheme for a dense OFDM system involving simple filters and an absolute reference

A frequency control scheme is introduced where within each transmitter its frequency is referenced to a silica based optical frequency discriminator, which in addition is locked to an absolute reference frequency. An absolute stability of /spl plusmn/1 GHz was achieved. As frequency-determining elements, coupler-based Michelson interferometers or coated gradient-index (GRIN) lenses were used. The described set-up is employed in an OFDM based optical crossconnect-demonstrator (RACE 2065; COBRA).