Experimental demonstration of 84 Gbps QPSK signal’s 4-symbol all-optical pattern recognition

Abstract

In the F5G era, a promising all-optical processing technology named all-optical pattern recognition has attracted more and more attention. Its applications include not only all-optical header recognition or address recognition in OCDMA but also optoelectronic firewalls. The higher the recognition rate of pattern recognition, the higher the processing rate of both applications can reach. To meet the development features of eFFB in F5G, high-speed all-optical pattern recognition should be achieved. In this paper, a QPSK all-optical pattern recognition system with a data rate of up to 84Gbps is proposed, analyzed, and experimentally demonstrated by employing commercial independent optical components. The system first converts the I branch of the input QPSK signal to a positive and a negative IM signal by adding the coherent carrier from the orthogonal polarization. Then the converted IM signals are coupled into time delay lines and optical AND logic gates implemented by HNLFs to achieve the optical correlation operation. In the end, a high-level optical pulse indicating the pattern recognized result is output. Numerical simulation results reveal that the proposed system can recognize the target sequence from the I branch of the input sequence and the position of the output high-level pulse in the time window of the I branch of the input sequence is the position of the last symbol of the target sequence. The results of the experiment demonstrate that the proposed system can recognize a 4-symbol target sequence from the I branch of an 8-symbol 84Gbps QPSK input sequence, which proves the all-optical pattern recognition of QPSK signals.