Abstract: An Ethernet passive optical network (EPON) ring for providing protection against fiber failures. The optical network unit (ONU) is coupled to the ring fiber by a three-port passive optical splitting module that has three two-way optical passages. By the three two-way optical passages, the OUN receives/transmits data from/to the two ends of the optical line termination (OLT) to provide protection while the fiber failure. Moreover, it provides better authorization of users and simpler collision detection by the two-way transmission of the three-port passive optical splitting module to prevent hackers from invading and to reduce collisions.

Abstract: An Ethernet passive optical network (EPON) ring for providing protection against fiber failures. The optical network unit (ONU) is coupled to the ring fiber by a three-port passive optical splitting module that has three two-way optical passages. By the three two-way optical passages, the OUN receives/transmits data from/to the two ends of the optical line termination (OLT) to provide protection while the fiber failure. Moreover, it provides better authorization of users and simpler collision detection by the two-way transmission of the three-port passive optical splitting module to prevent hackers from invading and to reduce collisions.

Abstract: A method of positioning reflecting mirrors inside a multi-level optical switch. The multi-level optical switch has a plurality of input terminals and a plurality of output terminals. A first fixed single-sided reflecting mirror and a second fixed single-sided reflecting mirror are installed such that the reflecting surfaces of the first and the second fixed single-sided reflecting mirrors face each other and are parallel to each other. The input terminals are divided into an odd group and an even group. Cross-points of optical paths are computed by feeding the input light paths from the odd group and the even group using a network exchange algorithm. Double-sided reflecting mirrors are positioned at the corresponding optical path cross-points in the double-sided reflecting mirror layout region of the multi-level optical switch.

Abstract: A multi-mirror reflection optical switch structure having two fixed reflecting mirrors and a plurality of parallel positioned double-sided reflecting mirrors, each capable of being raised or lowered. The plurality of double-sided reflecting mirrors are positioned along two to three 45° parallel axes that run from the upper lefthand corner to the lower righthand corner of the optical switch. Each double-sided reflecting mirror can be raised or lowered in order to perform the rearrangeable non-blocking one-to-one function of the 4-by-4 optical switch.

Abstract: A method of positioning reflecting mirrors inside a multi-level optical switch. The multi-level optical switch has a plurality of input terminals and a plurality of output terminals. A first fixed single-sided reflecting mirror and a second fixed single-sided reflecting mirror are installed such that the reflecting surfaces of the first and the second fixed single-sided reflecting mirrors face each other and are parallel to each other. The input terminals are divided into an odd group and an even group. Cross-points of optical paths are computed by feeding the input light paths from the odd group and the even group using a network exchange algorithm. Double-sided reflecting mirrors are positioned at the corresponding optical path cross-points in the double-sided reflecting mirror layout region of the multi-level optical switch.