Optical link protection switch provides both Manual and Automatic switching mode. In Manual mode, the system switches optical path only based on the commands from user. In the Automatic mode, the system switches based on the power level detected and the preset threshold. Under automatic mode, the system can be set to be reverted or Non-reverted modes. Under Reverted mode, the system switches back to the working path automatically after the fault condition is cleared. Under Non-reverted mode, the system does not switch back.