Multi-core fiber could significantly increase the transmission capacity of fiber transmission systems.However

due to the crosstalk among adjacent cores

there exists a larger challenge for the resource allocation in Elastic Optical Networks（EONs）with multi-core fibers.In this paper

the problem of the Routing

Spectrum and Core Allocation（RSCA）in EONs with multi-core fibers is analyzed.We establish an optimization model that considers the crosstalk among adjacent cores and minimizes the maximum sequence number of frequency slots occupied.To the best of our knowledge

an optimization algorithm based on co-evolution is proposed to solve the RSCA problem for the first time.In the proposed algorithm

the first strategy of the most requested service is used to sort the traffic demand in descending order

and then the different routing and core allocation populations with integer coding are set up.Combined with single point crossover and uniform mutation

the global optimal solution of the RSCA problem is searched by the differentiated elite reserve evolution strategy.The performance evaluation of the proposed algorithm is conducted on two different network topologies.Experimental results show that the proposed algorithm could improve the efficient of the network spectrum resources usage and make the traffic bearing distribution more uniform.