With the increasing of high-bit-rates transmission over optical fiber and especially with the appearance of packet-switched networks, optical correlation detection technology will have many applications in future telecommunication systems including IP router. Beginning with the basic theory of the optical correlator based on fiber dispersion, the influence of the bandwidths of different light sources on the performance of optical correlator is compared by using theoretical analysis and numerical simulation, and phase noise converted into intensity noise by dispersion is analyzed. So it concludes that intensity noise is related with the light source bandwidth, and the signal-to-noise ratio of the optical correlation can be changed when using light source with different bandwidths. According to the simulation results, it is demonstrated that optical correlator based on incoherent light source can recognize 8-bit and 16-bit patterns in 10-Gb/s data streams, but correlation detection of 32-bit patterns can only use coherent light source. Besides, potential application of optical correlator based on incoherent light in the detection of the analog signal is discussed.