Direct generation of all-optical random numbers from optical pulse amplitude chaos

Institute of Optoelectronic Engineering, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
Optics Express (Impact Factor: 3.49). 02/2012; 20(4):4297-308. DOI: 10.1364/OE.20.004297
Source: PubMed


We propose and theoretically demonstrate an all-optical method for directly generating all-optical random numbers from pulse amplitude chaos produced by a mode-locked fiber ring laser. Under an appropriate pump intensity, the mode-locked laser can experience a quasi-periodic route to chaos. Such a chaos consists of a stream of pulses with a fixed repetition frequency but random intensities. In this method, we do not require sampling procedure and external triggered clocks but directly quantize the chaotic pulses stream into random number sequence via an all-optical flip-flop. Moreover, our simulation results show that the pulse amplitude chaos has no periodicity and possesses a highly symmetric distribution of amplitude. Thus, in theory, the obtained random number sequence without post-processing has a high-quality randomness verified by industry-standard statistical tests.

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Available from: Jian Z Zhang, Dec 29, 2013
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    • "As an example, the time delay is susceptible to detection by Eve [19]–[25]. Semiconductor lasers subject to optical feedback are commonly employed to generate chaotic signals for potential applications in chaos-based communications [12], key exchange [9], random bit generation [26]–[30], and so on. Recently , it has been shown that the time delay signature in chaotic lasers can be easily extracted by using statistics approaches, such as autocorrelation function (ACF) and delayed mutual information (DMI) [31]–[34]. "
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    ABSTRACT: The concealment of time delay signature of chaotic signals, which are generated by a slave laser (SL) with dual-chaotic optical injections (DCOI) from two external-cavity master lasers (MLs), is investigated numerically. Under certain circumstances, the SL can generate complex and wideband chaotic signals by adopting DCOI. Two scenarios of time delay concealment are identified by adjusting the injection strength and frequency detuning. Both the time delays of MLs can be masked simultaneously or only one of them can be eliminated. It is shown that enhanced two-channel optical chaotic communication using isochronous synchronization is successfully achieved, when twin semiconductor lasers are driven by the time delay eliminated chaotic signal. Moreover, this two-channel approach can be extended to any communication systems using complex chaotic signals generated by a small network of coupled semiconductor lasers. Our results are also valuable for understanding the characteristics of time delay signatures in laser networks and chaos-based multiplexing systems.
    Full-text · Article · Jul 2013 · IEEE Journal of Selected Topics in Quantum Electronics
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    ABSTRACT: Random bit generation is experimentally demonstrated using a semiconductor laser driven into chaos by optical injection. The laser is not subject to any feedback so that the chaotic waveform possesses very little autocorrelation. Random bit generation is achieved at a sampling rate of 10 GHz even when only a fractional bandwidth of 1.5 GHz within a much broader chaotic bandwidth is digitized. By retaining only 3 least significant bits per sample, an output bit rate of 30 Gbps is attained. The approach requires no complicated postprocessing and has no stringent requirement on the electronics bandwidth.
    Preview · Article · Jun 2012 · Optics Letters
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    ABSTRACT: The unpredictability degree and bandwidth properties of chaotic signals generated by semiconductor lasers subject to dual chaotic optical injections (DCOI) are investigated numerically. The unpredictability degree is evaluated quantitatively via permutation entropy. Compared with the slave laser (SL) subject to single chaotic optical injection, both the chaotic bandwidth and the unpredictability degree can be enhanced significantly for SL with DCOI. The effects of injection strength, frequency detuning as well as feedback strength are considered. It is shown that, with the increase of injection strength, the unpredictability degree of chaotic signals generated by SL increases firstly and then decreases until saturates at a constant level. Positive frequency detuning is preferred to achieve wideband unpredictability-enhanced chaos, and higher bandwidth and unpredictability degree can be further expected by adopting two differently detuned master lasers. The physical mechanisms behind the wideband unpredictability-enhanced chaos are also revealed. The wideband unpredictability-enhanced chaotic signals generated by SL with DCOI are extremely useful for high speed random number generators, as well as for high capacity security-enhanced chaotic communications.
    No preview · Article · Aug 2012 · IEEE Journal of Quantum Electronics
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