Abstract
We report a prototype of high-speed real-time physical random bit generator based on a chaotic laser. The chaotic laser consists of a semiconductor laser with optical feedback in fiber external cavity configuration. The chaotic laser intensity signal is quantized into binary stream by differential comparison which makes the amplitude distribution symmetric with respect to zero mean value. An exclusive-OR gate operation between two raw binary streams from the chaotic signal and its delayed signal is used to overcome the influences of the weak periodicity induced by the external cavity resonance inherent in the chaotic laser. After exclusive-OR operation, the prototype can generate a single fast random bit stream in real time without any off-line processing procedures. Its bit rate can be handily and continuously tuned up to 4.5 Gbps by a trigger clock. Experiment results demonstrate that our generator possesses high-quality randomness with verified by the three-standard-deviation criterion and industry-benchmark statistical tests.
Highlights
Random bit or number generators are key ingredients in a large number of fields such as scientific computations [1], stochastic experiments [2], cryptography [3] and communications [4]
We report a prototype of integrated physical random bit generator
The LD connects to an 80:20 optical fiber coupler (FC) whose principal output passes through a variable optical attenuator (VA) onto a optical circulator (OC), forming the fiber feedback cavity with a time delay on 74 ns and a feedback strength of 40%
Summary
Random bit or number generators are key ingredients in a large number of fields such as scientific computations [1], stochastic experiments [2], cryptography [3] and communications [4]. In contrast to pseudo-random bit generators, physical random bit generators can offer non-determined random bits and ensure the confidentiality, because they commonly operates by measuring unpredictable physical processes such as thermal noise from a resistors [6], frequency jitter of an oscillator [7], elapsed time between emission of particles during radioactive decay [8], electrical chaos in nonlinear circuits [9] and photonevents in attenuated light [10,11,12,13] These conventional physical random bit generators have been limited in bandwidth to very slow rates at Mbps and do not satisfy completely the requirements of unconditional secure modern communications with data rates at Gbps.
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