Method of making and structure for monolithic optical circuits

A method for making a multilevel monolithic optical circuit on a supporting surface, said optical circuit consisting of conductors on at least two levels with optical coupling of conductors on one level to optical conductors on the second level through optical conductive columns, comprising the steps of

• preparing the supporting surface to be reflective to light in said circuit at the interface between light conductors of said circuit and said surface,
• spreading a layer of liquid radiation sensitive plastic on said surface to a thickness desired for said conductors of said circuit,
• exposing said radiation sensitive plastic to radiation in a pattern desired for said conductors, thereby to harden said liquid radiation sensitive plastic to form said circuit conductors on a first level,
• washing away unexposed liquid radiation sensitive plastic,
• coating said pattern of optical conductors thus formed on said support surface with liquid radiation sensitive cladding material that will assure light in said conductors on said first level to be reflected by the interface between said conductors and said coating material,
• exposing said radiation sensitive cladding material except over specified areas of conductors of said first level where optical coupling is to be made with conductors of said second level, thereby to harden said radiation sensitive cladding material except over said specified areas,
• washing away said unexposed radiation sensitive cladding material over said specified areas,
• spreading a second layer of liquid radiation sensitive plastic on said radiation sensitive cladding material and allowing said liquid radiation sensitive plastic thus spread to fill areas where radiation sensitive cladding material has been washed away, said second layer of liquid radiation sensitive plastic having an index of refraction substantially the same as said first layer of liquid radiation sensitive plastic used to form said first level of conductors,
• exposing said second layer of radiation sensitive plastic to radiation in a desired pattern for said conductors, thereby to harden said second layer of liquid radiation sensitive plastic to form a second level of conductors with optical coupling to said first level of conductors, and
• coating said second level of conductors of said optical circuit thus formed with material that will assure light in said conductors to be reflected by the interface between said second level of conductors and said coating material.