Security Performance Enhancement Researching Of OCDMA System

In the information age, information sharing is becoming commoner and commoner, and the new technology changes with each passing day. Secure and reliable transmission of information with high speed becomes more and more important and has a closer relationship with people's vital interests. In the three main secure transmission technologies of optical information, Quantum communication can ensure the absolute security of information transmission, but at present the communication speed that has realized is still very low and limits its application. For chaotic communication, there are still many technical bottlenecks to be solved. The excellent performances of optical code division multiple access(OCDMA)technology make it become one of the most promising and most potential technologies, and attract more and more researchers' attention. When facing the hacking attacks, such as differential detection, code word intercept and so on, OCDMA system still has some security vulnerabilities, so it is necessary to further research the OCDMA safety subject to more adequately explore and use the advantageous safety properties of OCDMA system.This subject comes from the national defense pre-researching project "Optical CDMAXXXX", innovation points theory of this paper are as follows.1) The solution of using Sagnac exclusive or(XOR) logic gate to encrypt the data information to make up the security loophole of 2-Code Shift Keying(2-CSK) OCDMA system is put forward, then the quantitative analysis of safety performance when single user and multi-user at work respectively is demonstrated. The quantitative analysis shows that the bit-correct-eavesdropping probability is much smaller than the square of the probability in2-CSK OCDMA system without encryption and the safety performance is more excellent than that of the best solution promised at present. On OptiSystem software platform, the encrypted OCDMA system with Sagnac XOR logic gate is built and the scheme's feasibility is verified.2) Reconfigurable encoder scheme realized by all-optical Sagnac XOR logic device is come up with, then the simulation of OCDMA system with 1Gb/s speed built by the reconfigurable encoder and optical delay line decoder is finished and verify that the scheme isfeasible successfully. The reconfigurable encoder scheme can greatly improve the system's secure performance and is the simpler and more effective scheme choice at present.3) Reconfigurable two-dimensional OCDMA encoder and decoder scheme on the basis of wavelength selection switch(WSS) is put forward, then the experiment system with 10Gb/s speed based on the reconfigurable OCDMA encoder and decoder scheme is built, the optical transmission experiment with 40 Km transmission distance and without error is finished and verify that the scheme is feasible successfully. Quantitative analysis of the security performance shows that the scheme can effectively improve the system's transmission security and increase the selectable types of reconfigurable OCDMA encoder and decoder.