Ex Parte Akasaka

Board of Patent Appeals and Interferences

Mar 29, 2007

10655901 (B.P.A.I. Mar. 29, 2007)

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for publication and is not binding precedent of the Board.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 YOUICHI AKASAKA
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Appeal 2007-0680
Application 10/655,901
Technology Center 3600
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Decided: March 29, 2007
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Before ROBERT E. NAPPI, LINDA E. HORNER, and ANTON W.
FETTING Administrative Patent Judges.

NAPPI, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on appeal under 35 U.S.C. § 6(b) of the final
rejection of claims 1, 4 through 11 and 14 through 20. For the reasons stated
infra we will not sustain the Examiner’s rejection of these claims.

INVENTION

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The invention is directed to an amplifier for an optical communication
system. A light beam used to provide pumping power is split, a portion is
coupled to a fiber in the direction counter to the direction of the signal
propagation. The other portion is coupled to a second fiber in the direction
of signal propagation in that fiber. See page 3 of Appellant’s specification.
Claim 1 representative of the invention and reproduced below:
1. A communication system for distributed Raman amplification of
optical signals, the communication system comprising:
a first fiber span;
a second fiber span;
a third fiber span;
a first pump system configured to generate and transmit a first light
beam;
a first splitter configured to receive the first light beam, split the first
light beam into a first portion of the first light beam and a second portion of
the first light beam, transfer the first portion of the first light beam onto the
first fiber span to backward propagate over the first fiber span, and transfer
the second portion of the first light beam onto the second fiber span to
forward propagate over the second fiber span;
a second pump system configured to generate and transmit a second
light beam; and
a second splitter configured to receive the second light beam, split the
second light beam into a first portion of the second light beam and a second
portion of the second light beam, transfer the first portion of the second light
beam onto the second fiber span to backward propagate over the second
fiber span, and transfer the second portion of the second light beam onto the
third fiber span to forward propagate over the third fiber span;
wherein a power of the first portion of the first light beam is not equal
to a power of the second portion of the first light beam; and
wherein a power of the first portion of the second light beam is not
equal to a power of the second portion of the second light beam.

REFERENCES

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The references relied upon by the Examiner are:

Grubb US 6,344,922 B1 Feb. 5, 2002

Fidric US 6,603,593 B2 Aug. 5, 2003

C.R.S. Fludger et al. (Fludger), “Pump to Signal RIN transfer in
Raman Fibre Amplifiers” Electronics Letters, Vol. 37, No. 1, Jan. 4, 2001 pp
15-17.

Govind P. Agrawal, Fiber-Optic Communication Systems, 3rd Edition,
Wiley Interscience, May 28, 2002, pp. 243-246.

REJECTION AT ISSUE
Claims 1, 4, 11, and 14 stand rejected under 35 U.S.C. § 103 (a) as
being unpatentable over Grubb in view of Fludger. The Examiner’s
rejection is set forth on pages 3 and 4 of the Answer. Claims 5, 6, 8, 15, 16,
and 18 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over
Grubb in view of Fludger and Fidric. The Examiner’s rejection is set forth
on pages 4 and 5 of the Answer. Claims 7, 9, 10, 17, 19, and 20 stand
rejected under 35 U.S.C. § 103(a) as being unpatentable over Grubb in view
of Fludger and Agrawal. The Examiner’s rejection is set forth on pages 5
and 6 of the Answer. Throughout the opinion we make reference to the
Brief and Reply Brief (received May 2, 2006 and July 28, 2006
respectively), and the Answer (mailed June 26, 2006) for the respective
details thereof.
ISSUES
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Appellant contends that the Examiner’s rejection of independent
claims 1 and 11 under 35 U.S.C. § 103(a) is in error. Appellant argues that
Fludger does not discuss the effects on RIN1 in a fiber that is both forward
and reversed pumped with unequal power. Further, Appellant argues that
because Fludger teaches that counter-pumping is favored over co-pumping,
Fludger teaches away from combined forward and reverse pumping
implemented simultaneously over a single length of fiber, as taught by
Grubb (Br. 7-9).
The Examiner asserts that the rejection is proper. The Examiner
states, on page 7 of the Answer, that simultaneous forward and backward
pumping and an uneven split of a single light beam are not limitations
recited in the independent claims. Further, the Examiner asserts that Fludger
is directed to performance over a transmission system.
Appellant rebuts the Examiner’s claim interpretation in the Reply
Brief, asserting the independent claims 1 and 11 recite simultaneously
forward and reverse pumping a fiber strand and an uneven split of a single
light beam (Reply Br. 3-4).
Thus, the issues before us are whether the independent claims recite
simultaneously forward and reverse (co-pumping and counter-pumping) a
fiber strand, and an uneven split of a single light beam. The further issue is
whether the combination of the references teaches these limitations.

FINDINGS OF FACT

1 “RIN” stands for relative intensity noise (Fludger 16, left column).
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Grubb teaches many arrangements for optical communication
systems. Grubb teaches that optical pump energy can be supplied to an
optical fiber counter, and/or co-directionally to signal propagation (Grubb,
col. 9, ll. 10-26). Grubb teaches an arrangement in figure 5(a) where there
are several fiber segments 28, 30 and 40 and there are several pumping
sources (lasers items 32 and couplers 36). Figure 5(a) depicts the pumping
energy going through a distributor (item 24) and being coupled in manner
that appears to forward and reverse pump the fibers (note, signal propagation
is left-to-right, the splitters appear to provide pumping power to fibers to the
left (counter pumping) and the right (co-pumping)). However, the
description of figure 5(a) states that the pump source provides power
“counter-directionally to the optical signals being transmitted.” (Grubb, col.
9, ll. 28-33). Further, we note that Grubb states that distributor 24 is “known
in the art” and provides no explanation of whether it produces an even split
of the signal or an uneven split of the signal. Thus, we do not find
substantial evidence that the embodiment depicted in figure 5(a) teaches
splitting the power from one source to counter pump one fiber segment and
co-pump another segment or that the distributor (item 24) unequally splits
the beam.
Fludger teaches that systems which use Raman fiber amplifiers may
be co-pumped or counter-pumped (Fludger, introduction on p. 15). Fludger
discusses the effects of each on relative intensity noise (RIN). Fludger
concludes that in counter-pumped Raman amplification the different
directions of propagation cause the noise to be low pass filtered (Fludger,
conclusion on p. 17). We find no discussion in Fludger of splitting the beam
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of light from one pumping source into two unequal portions and counter-
pumping one segment with one portion of the beam and co-pumping another
fiber with the other portion of the beam.

ANALYSIS
Independent claim 1 recites “a first pump . . . to generate and transmit
a first light beam, a first splitter configured to receive the first light beam,
split the first light beam into a first portion of the first light beam and a
second portion of the first light beam, transfer the first portion of the first
light beam onto the first fiber span to backward propagate over the first fiber
span, and transfer the second portion of the first light beam onto the second
fiber span to forward propagate over the second fiber span.” Claim 1 also
recites a second pump and splitter which transfers light to backward
propagate the second fiber and forward propagate a third fiber. We find no
limitations that recite that the first, second or third fiber is simultaneously
forward and reverse propagated. We are not persuaded by Appellant’s
argument that the recitations of beam transmission by pumps of claim 1 must
be interpreted as simultaneous pumping, as the specification does not
contemplate one pump source to operate while the other is off. Claim 1
recites a system “comprising” various elements; this does not limit the claim
to a system containing only the recited elements, rather it is open ended and
encompasses any system that includes the recited elements. Further, before
the Office, claims are to be given their broadest reasonable interpretation.
We consider the Examiner’s interpretation to be reasonable and Appellant’s
asserted reading of simultaneous forward and backward pumping of a fiber
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span to be importing limitations from the specification into the claims.
Through a similar analysis we do not find that claim 11 recites simultaneous
forward and backward pumping of a fiber span.
Claim 1 also recites “wherein a power of the first portion of the first
light beam is not equal to a power of the second portion of the first light
beam; and wherein a power of the first portion of the second light beam is
not equal to a power of the second portion of the second light beam.” Thus,
claim 1 recites that the beam from the first pump is split into two unequal
parts and that the beam from the second pump is split into two unequal parts.
Accordingly, we disagree with the Examiner’s claim interpretation and find
that claim 1 recites an uneven split of a single light beam.
Having determined the scope of the claims, we next consider the art
applied to reject the claims. Independent claims 1 and 11 stand rejected over
Grubb in view of Fludger. The Examiner’s rejection relies upon the system
arrangement depicted in figure 5(a) of Grubb. As discussed supra, we find
that Grubb provides scant description of how the fiber segments 28, 30 or 40
are being pumped. Thus, we find that Grubb alone fails to provide
substantial evidence of using one laser through a splitter to forward pump
one fiber segment and reverse one fiber segment. As discussed supra,
Grubb is silent as to the operation of splitter 24 and as such fails to provide
substantial evidence of splitting a single beam in to two un-equal parts.
Further, we find no discussion in Fludger of splitting a beam into two
unequal parts. Thus, we do not find that the combination of Grubb and
Fludger teach all of the limitations of independent claims 1 and 11.
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We further note that the art used to reject the other dependent claims,
Fidric and Agrawal, does not teach splitting a beam into two unequal parts
and using the parts to forward pump one fiber segment and reverse pump a
second fiber segment.

CONCLUSION
We consider the Examiner’s rejection of claims 1, 4 through 11, and
14 through 20 under 35 U.S.C. § 103(a) to be in error as we do not find that
the combination of the combination of Grubb in view of Fludger teaches or
suggests the limitations in independent claims 1 and 11. The Examiner has
not asserted, nor do we find that Fidric or Agrawal, the references applied
against claims 5, 6, 7, 8, 9, 10, 15, 16, 17, 18, 19, and 20, make up for the
noted deficiencies in the rejection of independent claims 1 and 11.
Accordingly we will not sustain the Examiner’s rejection of claims 35
U.S.C. § 103 (a) of claims 1, 4 through 11 and 14 through 20.
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ORDER
For the forgoing reasons, we will not sustain the Examiner’s
rejections, under 35 U.S.C. § 103. The decision of the Examiner is reversed.
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JRG30
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SPRINT
6391 SPRINT PARKWAY
KSOPHT0101-Z2100
OVERLAND PARK, KS 66251-2100

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