the present invention provides an optical transceiver with a structure that is able to cope with both the heat - dissipation and the optical coupling of the sub - assembly with a butterfly package . the optical transceiver includes a frame , a receptacle member , a transmitter optical sub - assembly , a receiver optical sub - assembly , a substrate and a cover . at least one of sub - assemblies provides , what is called , a butterfly package assembled with the receptacle member . the assembly of the receptacle member with the sub - assembly is fixed to the frame with an elastomer put between the receptacle member and the frame . the sub - assembly is assembled with the receptacle member as satisfying the optical alignment , while , the assembly of the receptacle member and the sub - assembly is fixed to the frame in a unit . accordingly , the optical alignment and the fixing to the frame are consistently satisfied .