Patent ID: 7394954

Claim:
A method comprising: (a) receiving an optical signal to propagate in a first planar optical waveguide, the first planar optical waveguide comprising a first waveguide core within a first cladding, an upper surface of the first cladding over the first core being substantially flat along at least a portion of the length thereof and thereby forming a first substantially flat waveguide upper cladding surface, the first cladding having formed therein at least one additional area of first core material that forms a corresponding substantially flat first structural upper cladding surface substantially parallel to the first substantially flat waveguide upper cladding surface, the additional area of first core material being positioned so as to substantially avoid optical coupling with the first waveguide core; and (b) transferring by transverse-transfer at least a portion of the propagating optical signal from the first planar optical waveguide to propagate in a second planar optical waveguide assembled therewith, the second planar optical waveguide comprising a second waveguide core within a second cladding, an upper surface of the second cladding over the second core being substantially flat along at least a portion of the length thereof and thereby forming a second substantially flat waveguide upper cladding surface, the second cladding having formed therein at least one additional area of second core material that forms a corresponding substantially flat second structural upper cladding surface substantially parallel to the second substantially flat waveguide upper cladding surface, the first and second planar optical waveguides being assembled together with at least portions of their corresponding substantially flat structural upper cladding surfaces positioned against one another and with at least portions of their corresponding waveguide upper cladding surfaces facing one another, thereby positioning the first and second planar optical waveguides for optical transverse-coupling between the first and second cores along corresponding transverse-coupled portions thereof and enabling transverse-transfer of the optical signal, the additional area of second core material being positioned so as to substantially avoid optical coupling with the second waveguide core and to substantially avoid optical coupling with the first waveguide core, the additional area of first core material being positioned so as to substantially avoid optical coupling with the second waveguide core.