Spatially Multiplexed Quantum Entropy Source With Single LD for 100-Gbps Random Numbers and Beyond

Fast quantum random number (RN) generation is an essential technology for cryptographic applications requiring unpredictable RNs. This letter reports a spatially multiplexed quantum entropy source (QES) with a single laser diode (LD), utilizing parallel homodyne measurement of vacuum fluctuation, for an aggregated RN generation rate of 100 Gbit/s and beyond. The QES uses a high-power distributed feedback LD and a low-loss 1
$\times $
16 silica planar lightwave circuit splitter and achieves eight-channel parallel operation with a broad bandwidth of 4 GHz each. A four-channel aggregated RN generation rate of 4
$\times $
25 Gbit/s and further scalability up to
$8\times25$
Gbit/s with eight channels are demonstrated via offline post-processing.