Multiport beam splitter is a new research topic in quantum communication. To improve the security system, the dimension/capacity of quantum communication should increase. In this thesis, design, simulation and methodology of NXN multiport beam splitter on a photonic integrated circuit is explained. Photonic integrated circuit has more advantages than other optical components to design a multiport beam splitter. Multiport beam splitter on a photonic chip gives configuration stability, a compact prototype for future quantum network.