Wide dynamic range all-optical clock and data recovery from preamble-free NRZ-DPSK packets

We demonstrate an all-optical circuit that simultaneously performs packet-by-packet clock recovery (CR) and data demodulation from 10-Gb/s nonreturn-to-zero differential-phase-shift-keying packets. It includes a novel power equalizer based on a nonlinear self-polarization switch in a semiconductor optical amplifier that enables operations within 15-dB input power level fluctuations. Data demodulation is realized by a Gaussian narrow filter that simultaneously seeds a stage performing CR. CR is performed by a Fabry-Pérot filter-based circuit. By using the input packets as a gating signal, the circuit is able to extract clock packets with 0-bit rise and fall times. The circuit can operate asynchronously and with arbitrary packet length.