Eye-diagram measurement of 100 Gbit/s optical signal using optical sampling

Precise waveform measurement of optical short pulses is one of the key techniques in realizing ultrahigh-speed optical time-division-multiplexed (TDM) transmission systems. In particular, eye-diagram measurement is indispensable for the evaluation of transmission characteristics because it measures the waveforms of randomly modulated signals. The eye-diagram (randomly modulated waveform) of a 100 Gbit/s optical signal is successfully measured by using sum-frequency-generation optical sampling with 0.9 ps temporal resolution and more than 17 dB signal-to-noise ratio. The authors´ optical sampling method off-sets the low SNR of the measured waveform by employing an organic nonlinear crystal (AANP: 2-adamantylamino-5-nitropyridine) and by amplifying sampling pulses by over 200 W.