A cable assembly includes an insulative housing having a main portion, and a mating portion extending forwardly from the mating portion. An optical device is attached to the housing and has a pair of optical module movable accommodated in the mating portion along a front-to-back direction for optical transmitting. The optical modules each has a seat and a number of lenses supported by the seat. The pair of optical modules are adapted for connecting two corresponding connectors, respectively, and a combination of the pair of the optical modules is also adapted for connecting a single corresponding connector.