自脈動雷射二極體之混沌光的同步與數位傳遞

Abstract

藉由輸入一個 a+b sin2πft 的電流至自脈動雷射二極體，可以產生混沌光，給兩個這樣的混沌系統不同的初始值，為了達成其同步現象，我們根據Pecora和Carroll的理論，建立了驅動－－回應系統模型，假如此模型的CLE全部為負，則不論為單向或雙向的光子傳遞，其同步現象皆可達成。其次，在同步的狀況下，利用此模型在輸入電流參數上的改變，研究其數位訊號的混沌傳遞。接收端利用同步誤差函數的測量，將數位訊號還原，另外，該系統CLE之最大值與同步速度成比例，進一步決定了傳遞的速率。

Optical chaotic light can be obtained by injecting a sinusoidal electronic signal into a self-pulsating laser diode. To synchronize between two identical chaotic systems with different initial conditions, a drive and response system model is constructed according to Pecora and Carroll's theory. Synchronization can be achieved for optical simplex and duplex transmissions provided that the conditional Lyapunov exponents for the drive and response systems are all negative. In the context of synchronization, optical chaotic transmission of a digital signal is investigated by the input parameter switching using the drive-response model. The digital message can be reconstructed by measuring the synchronization error function in the receiving end. In addition, the first conditional Lyapunov exponent of the system is shown to be directly proportional to the synchronization speed and ultimately determine the transmission rate.