With the development of the research on integrated optical circuit devices,there is an increasing demand for multi-functional photonic crystal devices.Most of the currently reported photonic crystal devices are of single-band and single-function.To solve the problem of multi-band and multi-functional integration of optical beam splitters,this paper proposes a two-dimensional triangular-lattice photonic crystal beam splitter with an X-like configuration.This device functions as a dual-band four-channel splitter based on a multi-band,multi-functional integrated design approach.It is composed of three parts,namely the input channel,the dual-frequency coupling cavity and the output channel.Beam splitting can be achieved by this device in the dual-band four-channel.The transmission characteristics of light waves in this structure are analyzed by the finite-difference time-domain (FDTD) method.The results show that the structure achieves beam splitting simultaneously in two distinct bands.In the first band,the incident light wave with a wavelength of 1.437 μm is symmetrically split and output through the two right channels,with the total transmittance of 96.32%.In the second band,the incident light wave with a wavelength of 1.642 μm is symmetrically split and output through the two left channels,with the total transmittance of 82.36%.Moreover,the structure achieves excellent filtering characteristics in both bands,with filtering efficiencies of 99.5% and 88.2%,respectively.