For optical communication networks, the Wavelength Division Multiple Access (WDMA) system has been developed at first and maturely commercialized. Although WDMA can be used to satisfy the requirement mentioned above, it has the disadvantage of low efficiency in utilizing bandwidth (for the high bandwidth optical communication system). Thus, the Optical Code Division Multiple Access (OCDMA) is developed in order to alleviate the problem, but its data rate is limited by the low repetition rate of the ultrashort pulse laser source. Hence, in this paper, we propose a Multi-slot OCDMA system to resolve the issue of low data rate. Data rate and total throughput can really be increased with the increased number of slots with the proposed system. For example, if 512 chips are used for OCDMA system, the system can simultaneously accommodate more than 10 6-slot OCDMA and 30 WDMA users, achieving a total throughput of around 660Gbps at a BER of 10^-9.