| 摘要 |
<P>PROBLEM TO BE SOLVED: To generate a series which is quite unpredictable and to make security higher by performing spectrum spread processing using the series as spread codes. <P>SOLUTION: Four optical interferometers 41 to 44 are arranged in parallel and optical path length differences 52<SB>1</SB>to 52<SB>4</SB>of the respective optical interferometers are set to L, r×L, r×r×L, and r×r×r×L. Here, L is a unit optical path length difference (constant). A coefficient (r) by which the unit optical path length difference is multiplied by L is a real number which is not an integer, e.g. an irrational number. A surd, the ratio π of the circumference of a circle to its diameter, the bottom e of a natural logarithm, etc., such as √2 and √3 are irrational numbers. The optical path length differences are thus set and then a chaos dynamical system does not hold for the intensity of light outputted by the optical interferometers 41 to 44, so that the addition theorem does not stand up and no chaos mapping is present. In other words, the series which is quite unpredictable can be generated. This series is used as spread codes to perform spectrum spreading. <P>COPYRIGHT: (C)2003,JPO |
