Two-photon interference (TPI) occurring at a beam splitter was investigated. In this scenario, one input is a weak coherent state, while the other input can be injected into another weak coherent, thermal, or a single-photon state. In our single-mode TPI model, we factored in the ratio of the average photon number. By employing numerical calculations, we determined the two-photon coincidence events with average photon number ratio. Moreover, we accounted for the noise inherent in the detection system. The results suggest that the quality of TPI can be substantially enhanced by eliminating the two-photon components from two input sources. Average photon number ratio and system-induced noise are intimately connected to the actual performance of an experiment. The results may help us to open up novel pathways in quantum information technology, particularly in situations where TPI between different sources is essential.