In this paper, the 1×5 optical splitters (OSs) based on 2D rod-type silicon photonic crystal embed cascaded
self-collimation (SC) ring resonators (CSCRR) was proposed. The 1×5 OSs consist of eight beam splitters, which are
formed by varying the radii of the rod. With self-collimation effect, we can manipulate the light’s propagation in the OSs.
Here we consider TM modes. Utilizing multiple-beam interference theory, the theoretical transmission spectra at
different outputs were analysed. These transmission spectra can help us to set the radii of eight slitters properly, for we
can control the light coming out from five ports with the light-intensity ratio we need. Meanwhile these outputs’
transmission spectra were investigated by the finite-difference time-domain (FDTD) method. The simulative results have
an agreement with the theoretical prediction. The 1×5 OSs will have practical applications in photonic integrated circuits.