利用光反馈半导体激光器产生的混沌激光作为随机数发生器的物理熵源,分析了混沌信号自相关系数与随机序列游程数之间的联系,在此基础上研究了激光器的弛豫振荡频率fr与随机序列速率fn在不同比值时,序列游程数的变化情况.研究发现,当fr/fn=(2k+1)/4时,随机序列的游程数容易满足NIST SP800-22随机数测试标准的要求.当k=1时,得到随机序列最大速率为fn=4fr/3.
In this paper,chaotic light generated by semiconductor laser with optical feedback is employed as physical entropy source to generate high-speed random sequence.The relationship between autocorrelation coefficient of chaotic signal and run number of random sequence is analyzed.Based on the analysis,the changes of random sequence run number are further investigated at different ratios between laser relaxation oscillation frequency fr and random sequence generation rate fn.The results show that random sequence run can easily meet the requirement for run test of NIST SP800-22 when the ratio between fr and fn satisfies the equation of fr/fn = (2k + l)/4.When k in the equation is equal to 1,the maximal rate f_n = 4fr/3 of random sequence is obtained.