Ex Parte Yamazaki

Patent Trial and Appeal Board

Apr 30, 2013

11391204 (P.T.A.B. Apr. 30, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte HIROYUKI YAMAZAKI
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Appeal 2010-010648
Application 11/391,204
Technology Center 2800
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Before CAROLYN D. THOMAS, ELENI MANTIS MERCADER,
and JOHN A. EVANS, Administrative Patent Judges.

MANTIS MERCADER, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-010648
Application 11/391,204

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STATEMENT OF THE CASE
Appellant appeals under 35 U.S.C. § 134(a) from a final rejection of
claims 1-11 and 13-21. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

THE INVENTION
Appellant’s claimed invention is directed to a tunable laser which can
vary the oscillation wavelength thereof. Abstract.
Independent claim 1, reproduced below, is representative of the
subject matter on appeal.
1. A tunable laser comprising:
a multiple ring resonator comprising a plurality of ring resonators
connected in series and having respective ring-shaped waveguides and
respective different optical path lengths;
a single input/output side optical waveguide coupled to said multiple
ring resonator;
a single optical input/output device coupled to said single input/output
side optical waveguide, and said single optical input/output device
comprises a laser diode or a semiconductor optical amplifier;
a single reflection side optical waveguide coupled to said multiple
ring resonator at an end opposite to said single input/output side optical
waveguide;
an optical reflector coupled to said single reflection side optical
waveguide;
a single coupling waveguide coupling adjacent ring resonators;
a wavelength varying mechanism for changing the resonant
wavelength of said multiple ring resonator; and
a filter for preventing light in high-order modes from being introduced
into said multiple ring resonator and for propagating light in a fundamental
mode in said multiple ring resonator.

Appeal 2010-010648
Application 11/391,204

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REFERENCES and REJECTIONS
1. The Examiner rejected claims 1-6, 8, 10, 11, 14, 15, and 17-21 under
35 U.S.C. § 103(a) as being unpatentable over Margalit (WO
2004/034528 A2; Apr. 22, 2004) and Hiruta (JP 11052158 A; Feb.
1999).
2. The Examiner rejected claims 7 and 9 under 35 U.S.C. § 103(a) as
being unpatentable over Margalit and Hiruta and further in view of
Hanada (US Pub. App. 2003/0169965 A1; Sep. 11, 2003).1
3. The Examiner rejected claims 13 and 16 under 35 U.S.C. § 103(a) as
being unpatentable over Margalit and Hiruta and further in view of
Nikonov (US Pat. 6,522,812 B1; Feb. 18, 2003).

ISSUES
The issues are whether the Examiner erred in finding that
1. Margalit in view of Hiruta teaches the limitations of “different
optical path lengths” and a “single input/output side optical
waveguide”; and
2. there is adequate motivation to modify Margalit in view of Hiruta.

ANALYSIS
Appellant argues that the technology of Margalit requires symmetry
arising from the parallel optical resonators processing a split beam entering
optical resonators 203A and 203B at different points, and the optical

1 We note that while the Examiner omitted the reference of Hiruta from the
grounds of rejection for claims 7, 9, 13, and 16, (Ans. 6-7), this must have
been an inadvertent error since these are dependent claims and their
respective independent claims were rejected in view of Hiruta.
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Application 11/391,204

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resonators 203A and 203B are thus required to have the same optical path
lengths. In contrast, claim 1 of the present invention has resonators with
“different optical path lengths.” Appellant further argues that the geometry
of the multiple ring resonator, as claimed in claim 1, permits only one laser
beam to be input to the multiple ring resonator, and Margalit’s split beam
technology cannot be used. Appellant asserts that the resonator of Margalit
requires two light inputs. In contrast, claim 1 of the present invention has “a
single optical input/output device.” See App. Br. 15-16.
We do not agree with Appellant’s arguments. The Examiner finds
(Ans. 8-9), and we agree, that Margalit teaches a multi-stage resonator
formed by two or more rings arranged in a cascaded fashion between
waveguides 101 and 106A and/or between waveguides 101 and 106B,
provided the reflector element 208 is appropriately coupled to waveguide
106A (or waveguide 106B) depending on the design of the resonator
structure and the number of rings therein (see p. 16, ll. 11-15), which means
that the resonators with “different optical path lengths” can be implemented
by the different number of rings in this structure. We also agree with the
Examiner that the limitation of one laser beam, as argued, is not in the body
of claim 1, and Margalit teaches the limitation of “a single optical
input/output device” by disclosing an in/out of the beam through the
waveguide 101 (see p. 16, ll. 16-27).
Appellant does not contest that Hiruta teaches a mode filter to prevent
high-order modes, but argues that there is no teaching in Hiruta to combine
the mode filter with ring resonators (App. Br. 16, ll. 4-10).
We do not agree with Appellant’s argument. We agree with the
Examiner (Ans. 9) that it would have been obvious to a person of ordinary
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skill in the art at the time of invention to combine the mode filter of Hiruta
with a tunable laser of Margalit because that would have provided a
waveguide type optical circuit capable of eliminating high-order modes
efficiently (see Hiruta Abstract). We also agree with the Examiner that
Margalit’s tunable laser constitutes a waveguide type optical circuit having
ring resonators which would become more efficient modified with Hiruta’s
mode filter with ring resonators (Ans. 9).
Accordingly, we affirm the Examiner’s rejections of claim 1 and for
the same reasons the rejections of claims 2-11 and 13-21, which were not
separately argued.

CONCLUSIONS
The Examiner did not err in finding that:
1. Margalit in view of Hiruta teaches the limitations of “different
optical path lengths” and a “single input/output side optical waveguide”; and
2. there is adequate motivation to modify Margalit in view of
Hiruta.

DECISION
The Examiner’s decision rejecting claims 1-11 and 13-21 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).

AFFIRMED

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