Molded plastic optical fiber-optoelectronic converter subassembly

The process of specification for fabrication, of a lens for use in the transfer of signals between an optical fiber and an optoelectronic converter, in which the fabricated lens produces a focus, of the rays of light that pass through said lens, in a range along a common axis through said lens, by introducing longitudinal spherical aberration, in image space,

• wherein said longitudinal spherical aberration has a functional dependence on radial position from said common axis,
• said radial position being in the exit plane perpendicular to said common axis,
• said exit plane being tangent to the exit surface, from which light emerges, of said lens, at the point where said exit surface intersects said common axis, and
• and wherein said functional dependence is serpentine in form,
• comprising the steps of:
• establishing an initial set of lens specifications,
• including at least the members of the group of:
• the light conversion characteristics of said optoelectronic converter,
• the light responsive characteristics of said optical fiber,
• the tolerance ranges of the characteristics, and,
• the desired range of light power coupling efficiency and,
• iteratively determining, from said initial set of lens specifications and an initial set of values for adjustable parameters describing said longitudinal spherical aberration in image space, an optimized set of said adjustable parameters which are used to produce a set of machine parameters to which a lens surface shaping machine can respond, thereby forming a lens substantially satisfying said lens specification parameters.