Abstract: A single mode wideband polarization maintaining (PM) fiber coupler, including: a first PM fiber having a first core and a pair of first stress members configured to provide a first mechanical stress to the first core; and a second PM fiber having a second core and a pair of second stress members configured to provide a second mechanical stress to the second core; wherein a length of the first PM fiber is fused with a corresponding length of the second PM fiber, wherein at least one geometry among the first core and the pair of first stress members is different from a corresponding at least one geometry among the second core and the pair of second stress members, and the difference in the at least one geometry between the first and second PM fibers causes a frustrated coupling between the first and second PM fibers.

Abstract: Embodiments of the present invention provide data securing methods, systems, and computer program products for controlling data distribution in a distributed computing system comprising a set of nodes interconnected through a communication system and a shared data storage space, each node owning a part of the data maintained in the shared data storage space. Each node comprises a node manager for controlling access by producer and consumer nodes to the part of the shared data storage space owned by the associated node. The data securing system previously associates a first group among the group of consumer nodes and the group of producer nodes with a first trusting level and a second group among the group of consumer nodes and the group of producer nodes with a second trusting level. The node manager is configured to generate a common shared key to all members of the first group, and to generate a unique key for each member of the second group, the unique key for being derived from the common shared key.