20Â GHz nearly transform-limited switching-wavelength pulsed source for wavelength-division signal sampling

Nearly transform-limited switching-wavelength pulses at 20 GHz are successfully generated by frequency chirp compensation and pulse multiplication of a 4-switching-wavelength pulse train. The autocorrelation pulse width is measured to be 14.5 ps. The 20 GHz pulsed source has been successfully applied for use in wavelength-division photonic sampling of a RF signal. A 20 GSample/s photonic analog-to-digital converter (ADC) is realized and measurement results on the signal-to-noise and distortion ratio (SINAD) and the spurious-free dynamic range (SFDR) are obtained.