Patent ID: 6952534

Claim:
A method of generating return-to-zero (RZ) optical data in a digital lightwave communications system, comprising the steps: providing radio frequency (RF) electrical data to a first stage modulator for modulating a light input so as to generate an intermediary optical data output having a non-return-to-zero (NRZ) format; controlling a phase difference between said intermediary optical data output and a clock signal associated therewith using a feedback control loop operable responsive at least in part to a phase dither reference signal, wherein the step of controlling the phase difference comprises: providing an output generated by a synchronous (SYNC) detector operable to detect signal transitions in said optical data due to a phase difference between said intermediary optical data output and said clock signal to an amplifier stage, said SYNC detector operating responsive at least in part to an RF amplitude dither reference signal in an RF data amplitude feedback control loop associated with said first stage modulator; providing an output generated by said amplifier stage to a phase SYNC detector operating in response to said phase dither reference signal to generate a phase error signal; and providing said phase error signal to a phase error amplifier having its reference input grounded, said phase error amplifier operating to generate an output signal that is groomed into said phase control signal; adjusting said clock signal based on a phase control signal provided by said feedback control loop to generate a phase-adjusted clock signal; and providing said phase-adjusted clock signal to a second stage modulator operable to blank out a select portion of data intervals of said intermediary optical data output for creating optical data having an RZ format.