Appeal No. 1997-3303 Page 11
Application No. 08/171,126
to be deposited upon the resulting structure of the etching step (e), which is waveguide (103). We are
aware of no reason as to why one of ordinary skill in the art would have been motivated to delete the
waveguide coupling region that separates the waveguides (111) and (103). If the conducting material
were deposited upon the waveguide (103), the serially arranged grating directional couplers of Sakata
would not properly couple the light because Sakata utilizes forward coupling (col. 11, lines 65-67)
between the upper waveguide (111) and the common waveguide (103). As the two waveguides (103)
and (111) of Sakata form an asymmetric directional coupler and mode coupling occurs between the
two waveguides (figure 10 and col. 9, lines 1-12) one of ordinary skill in the art would have been taught
away from etching down to the waveguide in Sakata. Similarly, we are not in agreement with the
examiner’s statement (answer, page 9) that “it would have been obvious to one of ordinary skill in the
art to substitute the corrugated grating of Sakata with grating shaped electrodes. If we followed this
alternate line of reasoning by the examiner, the limitations of claim 12 would not be met for the same
reasons we stated, supra, i.e., claim 12 calls for the conductive material to be deposited upon the
resulting structure of the etching step (e), which is waveguide (103). If the corregated grating (114) of
Sakata were replaced with electrodes shaped as a grating, as advanced by the examiner, the
conducting material for forming the electrodes would be deposited upon cladding layer (104).
However, to meet method steps (e) and (f) of claim 12, the conductive material would have to be
deposited on the waveguide (103). To deposit the conducting material on the waveguide (103), layer
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