and may be for example molded to simplify manufacturing of module 10 it should be understood that the term u201c plastic u201d is used herein as a generic term to describe any non glass optical material that operates to transmit optical beams of interest therethrough and which can be conveniently formed into lenses and the like for example in most optical modules used at the present time the optical beams are generated by a laser that operates in the infra red band and any materials that transmit this light including some oxides and nitrides come within this definition in the preferred embodiment optoelectric package 12 is affixed to receptacle assembly 11 with flange 22 of ferrule 20 butting against the exposed surface of cover 48 further optoelectric package 12 is optically aligned with receptacle assembly 11 so that light from laser 45 is directed into core 15 of optical fiber 14 this alignment can be accomplished in different ways but one reliable method is known as active alignment in the active alignment process laser 45 is activated and receptacle assembly 11 is positioned approximately over optoelectric package 12 the light in optical fiber 14 is measured and the alignment is adjusted for maximum light when maximum light is measured alignment has been achieved and receptacle assembly 11 is fixed to optoelectric package 12 by some convenient means such.