Search

In the 5G era, more sensitive information will be transmitted on optical networks. Although modern cryptography could support different security mechanisms in different layers, the optical layer has not been paid enough attention but it is also vulnerable to attack by tapping or other methods. The optoelectronic firewall is one of the promising security strategies which can accelerate the operating speed within manageable costs by employing optical signal processing compared with current electronic firewalls. The most significant and challenging component of an optoelectronic firewall is pattern recognition. However, either the latest pattern recognition systems can only process the OOK or BPSK modulation format signals, or the coherent correlators supporting higher order modulation format require advanced components to deal with a higher number of symbols. In this paper, to address the pattern recognition challenges, we propose, analyze and simulate a pattern recognition system of QPSK signals integrated into all-optical high-speed optoelectronic firewalls used for optical layer security. The numerical simulation results first demonstrate the feasibility, and a baud rate of 100GBaud can be achieved. Next, a threshold-setting method is developed which also proves the ability to recognize arbitrary target patterns. Then some noise analysis results demonstrate that the pattern recognition of the I branch can be immune to the noise while the output power of EDFAs in the Q branch needs to be configured carefully. Finally, the matched result of a real Ethernet frame further reveals that our proposed system is promisingly applied in optoelectronic firewalls.

To achieve the all-optical pattern matching for optoelectronic firewall which could process high-speed optical signals efficiently, a BPSK all-optical pattern recognition system with the data rate up to 42 Gbit/s was proposed and demonstrated by employing the commercial optical components.First, the input BPSK sequence was converted to a positive and a negative IM signals by adding in-phase and inverse-phase coherent carriers, respectively.Then the converted IM signals were coupled into time delay lines and optical AND logic gates implemented by HNLF to achieve the optical correlation operation.In the end, a high-level optical pulse indicating the pattern matched result was output.The numerical simulation and the experiment results demonstrate that the proposed system can recognize a 4-bit target BPSK sequence from an 8-bit 42 Gbit/s BPSK input sequence, which proves the feasibility of the all-optical pattern matching of BPSK signals and can be applied to high-speed optoelectronic firewall.

Copyright of Journal on Communication / Tongxin Xuebao is the property of Journal on Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)