An optical interconnection assembly and method for the deployment and scaling of optical networks employing Spine-and-Leaf architecture has Spine multi-fiber optical connectors and Leaf multi-fiber optical connectors. The Spine optical connectors of the interconnection assembly are optically connected to multi-fiber connectors of Spine switches via Spine patch cords. The leaf multi-fiber connectors are optically connected to Leaf multi-fiber connectors of Leaf switches via Leaf patch cords. A plurality of fiber optic cables in said interconnection assembly serves to optically connect every Spine multi-fiber connector to every Leaf multi-fiber connector so that every Spine switch is optically connected to every Leaf switch. The optical interconnection assembly facilitates the deployment of network Spine-and-Leaf interconnections and the ability to scale out the network by using simplified methods described in this disclosure.