In this paper, we introduce an emergency optical network design problem for the low-cost post-disaster recovery of core optical transport networks. We take into account both the interconnection of the surviving multi-vendor resources and the utilization of portable emergency erbium-doped fiber amplifiers (EDFAs). The surviving multi-vendor optical nodes (e.g., reconfigurable optical add/drop multiplexer (ROADM) or wavelength cross-connect (WXC) nodes) and fiber links are the available resources during a disaster recovery and should be efficiently utilized first. The portable EDFAs are emergency resources added to replace the optical nodes that have either been destroyed or are down because of power outages. To solve this design problem, we propose an emergency network planning method using an integer linear programming (ILP) formulation such that the locations for the emergency interconnection of the multi-vendor networks and placement of the portable EDFAs are optimally selected. Evaluations show the benefits of the multi-vendor interconnection approach and utilization of emergency portable EDFAs.