Experimental demonstration of security-enhanced WDM-PON based on chaotic optical communications

Abstract

ABSTRACT The message-decryption process of subtracting chaotic synchronization carrier from receiving signal is explained by modeling and numerically solving the rate equations for semiconductor lasers. An experimental system of wavelength division multiplexing passive optical network (WDM-PON) base d on chaotic-light secure communications is first built up. The bidirectional transmissions of downstream and upstream data are experimentally realized with only two lasers and a single wavelength channel in a WDM fiber-optic link. When the data rate is 1.25 Gb/s, the secure transmissiondistance can be up to 11 km with SSMF of G.652. After sampling and decision, the BER of the recovered messages is calculated to be approximately 1 u 10  4 .Keyw ords: WDM-PON, message-security, chao tic laser, downstream, upstream 1. INTRODUCTION It is well-known that wavelength division multiplexing passive optical network (WDM-PON) is a good candida te forthe ne xt-generation passive optical-access-networks, and however, the traditiona l techniques for PON, includi ng EPON,GP ON and WDM-PON, are combining elec tric TDM with optical WDM, in whic h data are easily eavesdropped only bythe energy detection, therefore without any message security. So far, the software digital encryption techniques in general use have shortcomings such as complex realization, bad real-time, etc. The chaotic optical secure comm unicationis a hardware-based encryption technique at the physical layer, in which the message is hidden within the chaotic optical carrier during transmission and extracted at the receiver by chaos synchronization. It has attracted wide interest for itsadvantages of high security, high efficiency of encryption, high real-time ability and good compatibility with existing fiber-optic communication links and traditional software digita l encryption techniques. The application of chaotic op ticalsecure communication technique to WDM-PON is significant. However, So far, we haven’t seen an experimental system demonstration of chaotic-light based security-enhanced WDM-PON. In this paper, an experimental system of WDM-PON based on chaotic-light secure communications is first established. The communications of downstream and upstream data are experimentally realized with only two lasers and a singlewavel ength channel in a WDM fiber-optic link. Two 1.25 Gb /s-messages from downlink and uplink are hidden within the chaotic optical carrier for secure transmission. The transmission distance can be up to 11 km with G.652 fiber-optic ,and the bit error rate (BER) of the recovered message at each end of the communication is 10