**5. Conclusion**

Improving the degree of security or enhancing the performance of optical CDMA networks have their impacts on each other such that a decision has to be made for cases in which all or some of these requirements are desired but cannot be fulfilled. The tradeoffs between security and the performance in optical CDMA, based on Modified Double Weight (MQC) system, are presented . From the security viewpoint, optical CDMA designer should minimize the eavesdropper ability to detect code word pulses by controlling the authorized performance to reasonable throughput. Otherwise, error correction codes techniques used in commercial optical communications would be the solution to obtain the maximum acceptable system BER.
