Private correlated random bit generation based on multi-channel wideband chaos generation using optical frequency comb generation and parallel filtering
Yuehua An, Jiangwei Liu, Ziyang Ma, Zhitao Deng, Zhensen Gao
Correlated random bit generation (CRBG) plays an important role in secure communication, particularly for secure key distribution. In this work, we propose and numerically demonstrate a scheme of CRBG based on multi-channel broadband entropy sources and parallel filtering. In this scheme, a chaotic optical frequency comb generator is employed to produce a chaotic frequency comb with multi-channel low-correlated wideband chaos. Based on the commonly driven induced synchronization between two closed-loop distributed feedback lasers and chaotic frequency comb generation, synchronized multi-channel wideband chaos is achieved. Then, parallel filtering is implemented by utilizing an arrayed-waveguide grating to divide the chaotic frequency comb into multi-channel sub-carrier chaos with different wavelengths. To reduce the correlation among adjacent channels and improve the chaos complexity, beating frequency processing with different delay times among adjacent chaotic sub-carriers is performed to get several different sets of chaotic output, among which an enhanced bandwidth over 20 GHz and low correlations are obtained. Moreover, the correlation between the chaotic output and the driving signal can be further suppressed, indicating that the security of the scheme is guaranteed. Multi-channel high-speed CRBG with a total generation rate of 16 Gb/s is successfully achieved at two legitimate users after transmission, with the randomness of multi-channel correlated bit generation verified using a test suite from the National Institute of Standards and Technology. The proposed scheme may provide a way for high-speed multi-channel parallel correlated random bits based on commercial components, which could potentially find applications in future secure optical communication systems.
Correlated random bit generation (CRBG) plays an important role in secure communication, particularly for secure key distribution. In this work, we propose and numerically demonstrate a scheme of CRBG based on multi-channel broadband entropy sources and parallel filtering. In this scheme, a chaotic optical frequency comb generator is employed to produce a chaotic frequency comb with multi-channel low-correlated wideband chaos. Based on the commonly driven induced synchronization between two closed-loop distributed feedback lasers and chaotic frequency comb generation, synchronized multi-channel wideband chaos is achieved. Then, parallel filtering is implemented by utilizing an arrayed-waveguide grating to divide the chaotic frequency comb into multi-channel sub-carrier chaos with different wavelengths. To reduce the correlation among adjacent channels and improve the chaos complexity, beating frequency processing with different delay times among adjacent chaotic sub-carriers is performed to get several different sets of chaotic output, among which an enhanced bandwidth over 20 GHz and low correlations are obtained. Moreover, the correlation between the chaotic output and the driving signal can be further suppressed, indicating that the security of the scheme is guaranteed. Multi-channel high-speed CRBG with a total generation rate of 16 Gb/s is successfully achieved at two legitimate users after transmission, with the randomness of multi-channel correlated bit generation verified using a test suite from the National Institute of Standards and Technology. The proposed scheme may provide a way for high-speed multi-channel parallel correlated random bits based on commercial components, which could potentially find applications in future secure optical communication systems.
With the widespread application of big data, the amount of data transmitted through optical networks has been increasing dramatically. Correlated random bit generation (CRBG) is one of the key technologies in secure communication systems to ensure security performance and transmission efficiency. We propose and demonstrate a CRBG scheme based on a Mach–Zehnder modulator (MZM) electro-optic feedback loop to improve the security and speed of communication systems. In this scheme, common-signal-induced synchronization is accomplished to generate wideband complex physical entropy sources, and a private hardware module is employed to perform post-processing and nonlinear transformation of the synchronized signal. The simulation results show that the effective bandwidth of the output chaotic signal is significantly increased to 27.76 GHz, and high-quality synchronization with a correlation coefficient of over 0.98 is reached. A high-rate CRBG of up to 5.3 Gb/s is successfully achieved between two synchronized wideband physical entropy sources, and the hardware key space is enhanced to ∼242, which greatly improves the privacy of physical entropy sources. The proposed scheme provides a promising approach for high-speed private CRBG, which is expected to be used in high-speed secure key distribution and optical communication systems.
We propose and experimentally demonstrate a novel, to the best of our knowledge, private correlated random bit generation (CRBG) scheme based on commonly driven induced synchronization of two wideband physical entropy sources, which employs an open-loop distributed feedback laser followed by a hybrid electro-optic nonlinear transformation hardware module for effective bandwidth expansion and privacy enhancement. A Mach-Zehnder interferometer followed by an electro-optic self-feedback phase modulation loop as well as a dispersion element are constructed as a private hardware module to perform post-processing and nonlinear transformation of the synchronized signal. A record high rate of 5.2-Gb/s CRBG is successfully achieved between two synchronized wideband physical entropy sources with an enhanced entropy source rate and hardware key space. The demonstrated scheme may provide a new way for CRBG in future high speed secure communication systems.
We propose and experimentally demonstrate a novel, to the best of our knowledge, correlated random bit generation (CRBG) scheme in virtue of the synchronization of two physical entropy sources that are composed of a continuous-wave laser, a phase modulator that is driven by the output of a local laser subject to constant-amplitude and random-phase (CARP) injection, as well as a dispersive component. It is experimentally indicated that wideband complex physical entropy sources with an effective bandwidth of 22 GHz can be achieved, and high-quality synchronization with a large cross-correlation coefficient (∼0.95) can be achieved by introducing symmetric CARP injections into the local lasers at Alice and Bob ends. Based on this, two distributed CRBSs with a bit rate over 3 Gb/s and satisfactory consistency are independently generated at Alice and Bob ends; the excellent randomness of CRBSs is verified using a test suite of the National Institute of Standards and Technology.
Correlations existing between spectral components in multi-wavelength lasers have been the key challenge that hinders these laser sources from being developed to chaotic comb entropy sources for parallel random bit generation. Herein, spectrotemporally uncorrelated multi-order Stokes/anti-Stokes emissions are achieved by cooperatively exploiting nonlinear optical processes including cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing in a Brillouin random fiber laser. Chaotic instabilities induced by random mode resonance are enhanced and disorderly redistributed among different lasing lines through complex nonlinear optical interactions, which comprehensively releases the inherent correlation among multiple Stokes/anti-Stokes emission lines, realizing a chaotic frequency comb with multiple spectrotemporally uncorrelated channels. Parallel fast random bit generation is fulfilled with 31 channels, single-channel bit rate of 35-Gbps and total bit rate of 1.085-Tbps. National Institute of Standards and Technology statistic tests verify the randomness of generated bit streams. This work, in a simple and efficient way, breaks the correlation barrier for utilizing multi-wavelength laser to achieve high-quality spectrotemporally uncorrelated chaotic laser source, opening new avenues for achieving greatly accelerated random bit generation through parallelization and potentially revolutionizing the current architecture of secure communication and high-performance computation.
The exponential growth of data transmission and processing speeds in modern digital infrastructure requires entropy sources capable of producing large volumes of true randomness for information security. Chaotic emissions from semiconductor lasers are attractive in this context because of their fast dynamics and nonrepetitive behavior. Their spectral bandwidth, however, is typically limited to several tens of gigahertz, which constrains the achievable entropy rate and makes ultrafast random bit generation difficult without substantial post-processing. Here, we demonstrate a chaos-based entropy source that employs optical heterodyning between the chaotic emission from a semiconductor laser and an optical frequency comb, yielding a bandwidth exceeding 100 GHz and an experimentally verified single-channel entropy rate of 1.86 Tb/s. By directly extracting multiple bits from the digitized output of the entropy source, we achieve a single-channel random bit generation rate of 1.536 Tb/s, while four-channel parallelization reaches 6.144 Tb/s with no observable interchannel correlation. This linear scalability suggests that aggregate throughput could reach hundreds of terabits per second with additional parallel channels. The broadband, low-overhead photonic architecture presented here provides a viable route to real-time, ultrafast random bit generation with broad implications for secure communications, high-performance AI computing, and large-scale data analytics.
Physical random numbers (PRNs) own various advantageous characteristics, including unpredictability, non-repeatability, higher security and reliability. Meanwhile, laser chaos has attracted great attention in the field of PRN. In terms of single channel PRN, laser chaos schemes can achieve a much higher bit-rate than traditional quantum PRN schemes. So far, various laser chaos PRN schemes have been discussed in order to enhance the performance of single channel laser chaos PRN. However, considering the limited bandwidth of laser chaos, especially the bandwidth of digital electronic circuit, the development potential of single channel PRN should be limited and may fall into the trap of high performance and expensive cost. Recently, the applications of multi-channel parallel PRN schemes have been developed. These parallel types may balance the high performance of PRN in a low cost. Recent progress indicates that chaotic micro-comb may have good potential. The micro-comb exhibits highly nonlinear and complex dynamic characteristics, and each comb tooth may show chaotic oscillation. The wavelength division multiplexing technology enables large-scale optical parallel output, providing the possiblity for large-scale parallel PRN generation. However, most of these PRN schemes are offline rather than true online and real-time random numbers. Thus, the development of real, online real-time parallel PRN solutions has great interest and research value in related fields. Herein we experimentally demonstrat an ultra-high-speed parallel real-time physical random number generator, which is achieved though the combination of chaotic micro-comb of chip-scale Si3N4 ultra-high Q micro-resonator and a high-speed field programmable gate array (FPGA). The results show that the Si3N4 ultra-high Q micro-resonator generates a micro-comb with hundreds of channels, each channel can route into an optically chaotic state, and become an excellent physical entropy source. Using FPGA onboard multi-bit analog-to-digital converter, the filtered optical chaos signal from the micro-comb is discretely sampled and quantized, and resulting in an 8-bit binary bitstream. Taking real-time self-delayed exclusive or (XOR) processing of bitstream and preserving 4 least significant bits, the qualified physical random bitstream with real-time 5 Gbits/s rate is realized experimentally. Considering that there are 294 chaotic comb teeths, our approach anticipates a throughput of 1.74 Tbits/s of real-time physical random bits. Our results could offer a new integrated and ultra-high-speed option for real-time physical random number sources.