Receptacle ferrules with at least one monolithic lens system and fiber optic connectors using same are disclosed. Ferrule assemblies formed by mating plug and receptacle ferrules are also disclosed, as are connector assemblies formed by mating plug and receptacle connectors. The fiber optic connectors and connector assemblies are suitable for use with commercial electronic devices and provide either an optical connection, or both electrical and optical connections. The monolithic optical system defines a receptacle optical pathway having a focus at the receptacle ferrule front end. When a plug ferrule having a plug optical pathway is mated with the receptacle ferrule, the plug and receptacle optical pathways are optically coupled at a solid-solid optical pathway interface where light passing therethrough is either divergent or convergent, and where unwanted liquid is substantially expelled.