Silicon photonics based on SOI platform provides a viable solution for photonic network-on-chips (NoCs), since its advantages in large bandwidth, low delay and power-efficient. Optical router which is used to exchange data between the processor cores is a key component for the photonic NoCs. This paper reviews the latest research progress of optical router and introduces the general principle to build N-port non-blocking optical router using microring and Mach-Zehnder switching unit. The simulated results show that the optical router constructed by this method has least number of optical switches, lowest insertion loss, and lowest average power-consumption compared with optical routers of the same size reported before.