The effect of the coherence time of light sources on the performance of an incoherent temporal-spreading optical-code-division multiple-access (OCDMA) system is studied in this paper. Broadband noise-like light sources, such as amplified spontaneous emission (ASE) sources, are used by the transmitters. Three different kinds of receiver structures are examined and compared. Results show the impact of the nonideal light sources on the system performances relative to the ideal case. Analysis shows that to achieve the best performance when the available optical bandwidth and data rate are fixed, there is an optimal range for the spreading code length.