<p>Photonic ring waveguide resonators have great potential applications in wavelength filtering, switching, modulation and multiplexing. The response of coupled ring resonators can be designed by using various coupling configurations. Particularly, ring resonators can be used as wavelength filter when the wavelength fits a whole multiple times in the circumference of the ring. In this paper, we investigate the effect of input amplitude to power amplification in four ring resonator configurations and vary the input amplitude on five different wavelengths. With OptiFDTD Photonics Simulation Software V8.0, the results show the intensity phenomenon of filtering in optical circuit.</p><p> </p>