We propose a novel technique to increase the confidentiality of an optical code division multiple access(OCDMA) system.A virtual user technique is analyzed and implemented to make an OCDMA system secure.Using this technique,an eavesdropper will never find an isolated authorized user’s signal.When authorized users and virtual users transmit data synchronously and asynchronously,network security increases by 25% and 37.5%,respectively. We propose a novel technique to increase the confidentiality of an optical code division multiple access (OCDMA) system. A virtual user technique is analyzed and implemented to make an OCDMA system secure. Using this technique, an eavesdropper will never find an isolated authorized user’s signal .When authorized users and virtual users transmit data synchronously and asynchronously, network security increases by 25% and 37.5%, respectively.