  We propose and experimentally demonstrate an optical pulse sampling method
for photonic blind source separation. The photonic system processes and
separates wideband signals based on the statistical information of the mixed
signals and thus the sampling frequency can be orders of magnitude lower than
the bandwidth of the signals. The ultra-fast optical pulse functions as a
tweezer that collects samples of the signals at very low sampling rates, and
each sample is short enough to maintain the statistical properties of the
signals. The low sampling frequency reduces the workloads of the analog to
digital conversion and digital signal processing systems. In the meantime, the
short pulse sampling maintains the accuracy of the sampled signals, so the
statistical properties of the undersampling signals are the same as the
statistical properties of the original signals. With the optical pulses
generated from a mode-locked laser, the optical pulse sampling system is able
to process and separate mixed signals with bandwidth over 100GHz and achieves a
dynamic range of 30dB.
