40GHz clock generation using clock component enhancement modulation and band pass filtering

The applicability of clock and data superposed modulation for clock component enhancement In 40Gb/s NRZ signal was experimentally demonstrated. From this slgoal 40GHz clock was easily extracted by hand-pass filtering. The result showed 0.5dB power penalty Improvement with respect to a conventional clock extraction method of using noo-linear circuits. It is also pointed out that relative amplitude and phase of the two superposed modulation signals are very Important for good BER characteristics.