Fig. 1. Schematic of the proposed RBG with all-optical quantization: (a) optical chaos, (b) optical sampler, and (c) optical quantizer. DFB, distributed feedback semiconductor laser; PC, polarization controller; VA, variable optical attenuator; FM, fiber mirror; ISO, optical isolator; 3 dB, 3 dB FC; BPD, balanced photodiode; MLL, mode-locked laser; EOM, electro-optic modulator; EDFA, erbium-doped fiber amplifier; HNLF, highly nonlinear fiber; BPF, optical BPF.

Fig. 2. (a) RF spectra of the white chaos and ECL1,2 (the inset is the optical spectra of ECL1,2); (b) ACF of the white chaos (the inset on right upper corner shows ACFs of the ECL1,2); (c) temporal waveforms of the white chaos; (d) amplitude probability distribution of the white chaos.

Fig. 3. Schematic optical sampling results. (a) Continuous-time white chaotic waveform to be sampled; (b) discrete-time chaotic pulses after the optical sampler; (c) normalized CCF of the signal before and after the optical sampler.

Fig. 4. (a) Measured optical spectra from three SC pulses with different powers (45, 50, and 55 mW); (b) measured pulse waveform before (red) and after (blue) the threshold/quantization operation.

Fig. 5. (a) Bias |e[N]| versus the sample size of the generated 10 Gb/s random bits stream. The black dotted line in (a) is its three-standard-deviation line, 3σe=(3N−1/2)/2 where N=1,2,3,…,16Mbits. (b) AC coefficient C[K] as a function of the delay bit K for 16 Mbits.

Fig. 6. NIST test results: P-value (left column) and proportion (right column). Note, the 15 test items are shown along the horizontal axis.

Fig. 7. Frequency of “1” in a random bit sequence (red squares) and the number of passed NIST tests (blue circles) as a function of the filtering center wavelength λ0.