Ex Parte M et al

Board of Patent Appeals and Interferences

Jun 15, 2007

10020461 (B.P.A.I. Jun. 15, 2007)

The opinion in support of the decision being entered today
is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte HICHEM M’SAAD and ANCHUAN WANG
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Appeal 2007-1851
Application 10/020,461
Technology Center 1700
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Decided: June 15, 2007
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Before EDWARD C. KIMLIN, BRADLEY R. GARRIS, and
CHARLES F. WARREN, Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-4, 6-13, 15, 16,
and 21-42. Claim 1 is illustrative:
1. A method of forming an optical waveguide, the method
comprising:
flowing a silicon source gas into a process chamber;
flowing an oxygen source gas into the process chamber;

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forming a high-density plasma in the process chamber from the
silicon source gas and the oxygen source gas;
forming a plurality of separated silicate glass optical cores over
an undercladding layer disposed within the process chamber with the high-
density plasma, the separated silicate glass optical cores defining a sequence
of gaps; and
depositing an uppercladding layer over the plurality of
separated silicate glass optical cores,
wherein each of the silicate glass optical cores is formed with a
refractive index greater than a refractive index of the undercladding layer
such that each of the optical cores has a contrast relative to the
undercladding layer greater than 2%.
The Examiner relies upon the following references as evidence of
obviousness:
Dragone US 5,136,671 Aug. 4, 1992
Kyoto US 5,221,309 Jun. 22, 1993
Bazylenko US 6,154,582 Nov. 28, 2000
Johnson US 6,614,977 B2 Sep. 2, 2003
Applicants’ admission located at the bottom of page 3 of the paper of
Aug. 23, 2004
Appellants’ claimed invention is directed to a method of forming an
optical waveguide comprising a plurality of separated silicate glass optical
cores over an undercladding layer. The process involves forming a high-
density plasma from silicon and oxygen source gases in a process chamber,
and using the plasma to form the optical cores. The refractive index of the
silicate glass optical cores has a contrast relative to the refractive index of
the undercladding layer of greater than 2%.
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Appealed claims 1, 2, 15, 16, and 22-42 stand rejected under
35 U.S.C. § 103(a) as being unpatentable over Bazylenko and Kyoto in view
of Dragone and the admitted prior art. Claims 1-4, 6-13, 21-26, and 29-42
stand rejected under 35 U.S.C. § 103(a) as being unpatentable over Johnson
and Kyoto in view of Dragone and the admitted prior art.
Appellants have not presented separate arguments for claims 29-42.
Accordingly, the Examiner has properly held that claims 29-42 stand or fall
together with the remaining claims on appeal.
We have thoroughly reviewed each of Appellants’ arguments for
patentability. However, we are in complete agreement with the Examiner
that the claimed subject matter would have been obvious to one of ordinary
skill in the art within the meaning of § 103 in view of the applied prior art.
Accordingly, we will sustain the Examiner’s rejections for essentially those
reasons expressed in the Answer, and we add the following primarily for
emphasis.
We agree with the Examiner that the two primary references,
Bazylenko and Johnson, disclose, like Appellants, a method of forming a
silicate glass optical core over an undercladding using high-density plasma
deposition (HDP) in the formation of an optical waveguide. Bazylenko does
not explicitly disclose forming a plurality of silicate glass optical cores but,
from our perspective, the reference clearly would have suggested as much to
one of ordinary skill in the art. Bazylenko does expressly disclose that the
inventive method is used in preferred embodiments to form waveguide
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structures and waveguides(note the plural form) (see col. 2, ll. 40 and 44),
and the reference also discloses that the method is suitable “in fabricating
any type of device which combines optics with electronics in an integrated
form” (col. 3, ll. 5-7). As a result, we are persuaded that one of ordinary
skill in the art would have reasonably understood the Bazylenko method was
suitable for forming a plurality of silicate glass optical cores, as presently
claimed.
The obviousness of forming such a plurality of cores is further
supported by Dragone’s multiplexer which uses a plurality of optical cores.
Appellants’ arguments notwithstanding, the Examiner properly points out
that the claims on appeal do not require a waveguide that has multiple cores
and that Appellants’ Specification discloses that the present invention is
directed to making multiplexers. Hence, the appealed claims broadly
encompass making multiplexers of the type disclosed by Dragone.
We are also not persuaded by Appellants’ argument that the applied
references would not have suggested the refractive indices of the optical
cores having a contrast relative to the refractive index of the undercladding
layer greater than 2%. Bazylenko specifically teaches that the difference in
index of refraction between the optical core and the undercladding layer can
be “about 0.02,” or, about 2%, which would certainly include and suggest a
difference of somewhat greater than 2% (see col. 6, ll. 29-33). We perceive
no patentable distinction between the claimed “greater than 2%” and the
prior art disclosure of about 2% which includes values greater than 2%.
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Moreover, we fully concur with the Examiner that Kyoto firmly
establishes that it was known in the art to employ the pertinent difference in
index of refraction of greater than 2%. To wit, Kyoto discloses that for large
aperture optical fibers used in computer link communication applications, a
needed difference in index of refraction “is usually about 2 to 4%” (col. 1, ll.
52-54). While Appellants point to Example 1 of Bazylenko which has a
difference in index of refraction of 0.8%, it is well settled that a reference
must be considered for all that it fairly teaches, and such consideration is not
limited to exemplified embodiments. As for the Kyoto disclosure,
Appellants maintain that:
Kyoto merely mentions in passing that ”large aperture optical
fibers” may have contrasts of about 2 to 4%, without any
indication, explanation, or discussion of particular methods by
which one may be able to achieve such contrast levels, or the
applicability of such teachings to other types of fibers such as
waveguides with multiple cores.
(principal Br. 10, second para.). However, Appellants have presented no
convincing rationale, let alone objective evidence, which establishes that one
of ordinary skill in the art was not able to produce a contrast in the indices of
refraction from about 2 to 4%, as specifically disclosed by Kyoto. Also, we
note that the independent claims on appeal do not recite any particular
method steps for achieving a difference in index of refraction greater than
2%.
Johnson, the other primary reference, also does not specifically
disclose forming a plurality of silicate glass optical cores. However, like
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Bazylenko, Johnson discloses that the invention is directed to forming
optical waveguides and optical multiplexers (see col. 1, second para., and
col. 2, ll. 54-62). Consequently, we are satisfied that one of ordinary skill in
the art would have understood that the high density plasma deposition
method taught by Johnson can be used to form a plurality, and not just one,
silicate glass optical core over an undercladding. Again, we agree with the
Examiner that Dragone further evidences the obviousness of forming such a
plurality of optical cores. As for the difference in index of refraction of the
core and the undercladding, Appellants acknowledge that “Johnson does
disclose that the optical cladding can include any number of materials
having a lower index of refraction than the thin film forming the optical
component” (principal Br. 14, second para.). As discussed above, Kyoto, as
well as, for that matter, Bazylenko, evidences that a difference in index of
refraction of greater than 2% was conventional in the art.
Regarding separately argued claim 15, which calls for forming the
optical cores by etching a substantially continuous optical core layer,
Bazylenko expressly discloses that “[o]ther standard fabrication processes
(for example chemical etching) may be utilised with the method of the
present invention . . .” (col. 2, ll. 48 et seq.). Furthermore, as pointed out by
the Examiner, Dragone teaches the use of photolithographic techniques,
which include etching, to pattern the waveguides (see col. 6, ll. 41-46).
Appellants also separately argue claims 24-27, 31-33, and 39-41
which recite the use of nitrogen as a source gas. We do not subscribe to
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Appellants’ position that Bazylenko’s teaching away from using nitrogen
demonstrates the nonobviousness of doing so. Rather, Bazylenko relates a
disadvantage in using nitrogen, i.e., waveguides suffer from high losses in
the wavelength range of 1.50 to 1.55 μm due to a large absorption peak in
this region (see para. bridging cols. 1 and 2). Bazylenko establishes that the
use of nitrous oxides was well known in the art as an oxidant for silane, and,
therefore, we find that it would have been obvious for one of ordinary skill
in the art to use a source of nitrogen as an oxidant with the reasonable
expectation of experiencing the disadvantage taught by Bazylenko. It is well
settled that the omission of a feature disclosed by the prior art along with its
attendant advantage is a matter of obviousness for one of ordinary skill in
the art. In re Thompson, 545 F.2d 1290, 1294, 192 USPQ 275, 277 (CCPA
1976); In re Kuhle, 526 F.2d 553, 555, 188 USPQ 7, 9 (CCPA 1975); In re
Marzocchi, 456 F.2d 790, 793, 173 USPQ 228, 229-30 (CCPA 1972). In the
present case, Appellants have not demonstrated that their use of a nitrogen
source as an oxidant is not accompanied by the disadvantage set forth by
Bazylenko.
Concerning separately argued claims 2-11, 12, 22-28, 29-36, and
37-42, which recite pressure, temperature, and RF power densities within the
deposition chamber, we do not accept Appellants’ argument that “the
deposition conditions taught by Johnson do not amount to or suggest the
recited conditions for forming the high-density plasma as required by the
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claims” (Br. 15, last para.). While Appellants focus upon the plasma
enhanced chemical vapor deposition process described at column 7,
lines 13-22 of Johnson, Johnson teaches that a number of chemical vapor
deposition processes may be employed, such as Appellants’ high density
plasma chemical vapor deposition process (see col. 4, ll. 25 et seq.).
As a final point, we note that Appellants base no argument upon
objective evidence of nonobviousness, such as unexpected results, which
would serve to rebut the inference of obviousness established by the applied
prior art.
In conclusion, based on the foregoing and the reasons well stated by
the Examiner, the Examiner’s decision rejecting the appealed claims is
affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv) (2006).
AFFIRMED

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