Fig. 1. Schematic diagram of the proposed post-processing-free fast quantum random number generator (QRNG) based on optically sampling ASE. SLD, super-luminescent diode; EDFA, Er-doped fiber amplifier; BPF, optical band-pass filter; MLL, mode-locked laser; WDM, wavelength division multiplexer coupler; SOA, semiconductor optical amplifier; PC, polarization controller; 50:50, 50:50 optical coupler; TOAD, terahertz optical asymmetric demultiplexer; ISO, optical isolator; PD, photodetector; 8 bit quantizer, an 8 bit parallel comparator module built in a high-speed real-time serial data analyzer.

Fig. 2. Measured results of real-time optical sampling of the 625 MHz sinusoidal RF signal. (a) Temporal waveform of the 10 GHz MLL pulses out from the MLL. (b) Temporal waveform of the sampled pulses out from the EOM.

Fig. 3. Measured results of real-time all-optical quantization. (a) Temporal waveform of the sampled optical pulses to be quantized; (b)–(h) temporal waveforms (blue line) of the quantized output pulses from λ₁, λ₂, λ₃, λ₄, λ₅, λ₆, and λ₇ filtering channels, respectively. Note, red lines represent the synchronous temporal waveform of the input sampled pulses.

Fig. 4. Measured SCs from the 400 m HNLF with the average power of the sampled pulses increasing from 50 to 200 mW.