Experimental study on chaotic optical communication with PolSK modulation technology

Abstract

An experimental system used for the chaotic optical communication with the polarization shift-keying (PolSK) modulation technology is presented. In this experimental system, a semiconductor optical amplifier (SOA) based fiber-ring laser is taken as a dynamical chaotic transmitter and the states of polarization (SOPs) of the light wave is modulated through a cross phase modulation (XPM) effect in the SOA by the input message light. The chaotic receiver which is based on a time-delayed configuration can establish the synchronization with the transmitter, so that the transmitted message is restored from the chaotic carrier through a dynamical detection of SOPs of transmission light waves with two polarization detectors. A 5-km long single mode fiber was used as the communication channel. The round-trip time and SOPs of the fiber ring in this system are key parameters to establish the synchronization between the transmitter and receiver. The operation principle of the system was introduced and basic performances of the system were investigated. A chaotic transmission experiment with this system by using a 27-bit RZ sequence at 630 Mb/s was carried out and the message was successfully recovered from the chaotic carriers after 5-km long fiber transmission.