摘要 |
An Optical Frequency Division Multiplexing system achieves close channel spacings and thus high density of communications channels in a particular frequency band by providing a very precise carrier frequency stabilization technique. Each laser-generated local carrier signal is locked to a corresponding reference signal. All of the reference signals are generated by a common tunable laser circuit that produces a sequence of bursts of successively higher frequencies determined by resonant points of a single Fabry-Perot filter. Each transceiver of the Optical Frequency Division Multiplexing system includes a frequency tracking circuit that converts received signals from the optical domain to the electrical domain and utilizes an intermediate frequency filter circuit and a servo control circuit to adjust the tunable laser frequency and lock it to the present reference frequency. |