Ex Parte Partridge

Patent Trial and Appeal Board

Sep 24, 2018

14814426 (P.T.A.B. Sep. 24, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
14/814,426 07/30/2015
22878 7590
Agilent Technologies, Inc.
Global IP Operations
5301 Stevens Creek Blvd
Santa Clara, CA 95051
09/26/2018
FIRST NAMED INVENTOR
Guthrie Partridge
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
20150079-01 1024
EXAMINER
HAGAN, SEAN P
ART UNIT PAPER NUMBER
2828
NOTIFICATION DATE DELIVERY MODE
09/26/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
IPOPS.LEGAL@agilent.com
Agilentdocketing@cpaglobal.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL
AND APPEAL BOARD
Ex parte GUTHRIE PARTRIDGE 1
Appeal2018---002723
Application 14/814,426
Technology Center 2800
Before BEYERL YA. FRANKLIN, JEFFREY R. SNAY, and
MICHAEL G. McMANUS, Administrative Patent Judges.
FRANKLIN, Administrative Patent Judge.
DECISION ON APPEAL
1 Appellant identifies the real party in interest as Agilent Technologies, Inc.
Appeal2018-002723
Application 14/814,426
Appellant requests our review under 35 U.S.C. § 134 of the
Examiner's decision rejecting claims 1, 2, 4--7, 10, 11, and 13-15 (note: the
rejection of claims 8, 9, 16, and 18 has been withdrawn in the Answer ( Ans.
2)). We have jurisdiction over the appeal under 35 U.S.C. § 6(b).
STATEMENT OF THE CASE
Claim 1 is illustrative of Appellant's subject matter on appeal and is
set forth below:
1. An apparatus comprising:
a gain chip assembly comprising first and second gain chips that are
coupled optically such that light travels serially between said first gain chip
and said second gain chip, each gain chip being electrically biased, said
electrical bias of said first gain chip being independent of said electrical bias
of said second gain chip;
an external cavity having a tunable wavelength selective filter that
selectively passes light in a pass band that is changed in response to a
control signal, light in said external cavity passing through said gain chip
assembly; and
a controller that generates said control signal, and said electrical bias
of each of said gain,
wherein said first gain chip comprises an active layer comprising a
first sub-layer having a plurality of quantum well layers characterized by a
first quantum well thickness, said second gain chip comprises an active layer
having second and third sub-layers, said second sub-layer comprising a
plurality of quantum well layers characterized by a second quantum well
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Application 14/814,426
thickness, and said third sub-layer comprising a plurality of quantum well
layers characterized by a third quantum well thickness, said second and third
sub-layers being connected in series to said electrical bias of said second
gain chip, said first, second, and third quantum well thicknesses being
different from one another, and
wherein said first, second and third quantum well thicknesses are
chosen such that only one of said first, second, and third sub-layers supports
lasing at any given electrical biases of said first and second gain chips,
whereas a single gain chip having an active layer with said three sublayers
would support simultaneous lasing by two of said first, second, and third
sub-layers.
The Examiner relies on the following prior art references as evidence
of unpatentability:
Miller us 4,680,769 Jul. 14, 1987
Patel et al. US 2008/0159341 Al Jul. 3, 2008
Berger us 6,091,751 Jul. 18, 2000
Hong et al. us 6,104,739 Aug. 15, 2000
Lasher us 3,427,563 Feb. 11, 1969
Hirata et al. US 6,738,398 B2 May 18, 2004
THE REJECTIONS
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Application 14/814,426
1. Claims 1 and 5 through 7 are rejected under 35 U.S.C. § 103 as
being unpatentable over Miller in view of Patel, and further in view of
Berger.
2. Claims 2, 4, 10, 11, and 13 through 15 are rejected under 35 U.S.C.
§ 103 as being unpatentable over Miller in view of Patel, in view of Berger,
and further in view of Hong.
ANALYSIS
Upon consideration of the evidence on this record and each of the
respective positions set forth in the record, we find that the preponderance of
evidence on this record supports Appellant's position for the reasons
provided by Appellant therein. Accordingly, we reverse each of the
Examiner's rejections on appeal, and add the following for emphasis.
Claim 1 requires that the apparatus have two gain chips with three
different active layers, one on the first chip, and two on the second chip. The
active layers on the second chip are connected in series. The active layers
are constructed with quantum well thicknesses that are different. In
addition, the thicknesses are chosen such that at any given bias of the first
and second gain chips, only one of the active layers supports lasing. Finally,
the active layers are chosen such that two of said active layers would
simultaneously support lasing if all three active layers were connected in
series in a single gain chip.
We refer to pages 10-14 of the Final Office Action regarding the
Examiner's rejection of claims 1 and 5-7. Therein, the Examiner relies
upon Miller for disclosing a gain chip assembly having two gain chips that
are arranged such that light passes serially through the chips. The Examiner
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Application 14/814,426
finds that each chip in Miller has a single active region. The Examiner finds
that the quantum well layers in the first chip have a different thickness than
the quantum well layers in the second chip. The Examiner finds that Miller
teaches that only one of the active layers in the two chips lases at any
wavelength. The Examiner relies upon Berger for teaching a gain chip
having two different quantum well layers with different thicknesses that are
connected in series and biased by the same current. The Examiner relies
upon Patel for teaching active layers having a plurality of sub-layers having
a plurality of quantum well layers. The Examiner argues that one would
have been motivated to have used the chip taught in Berger in place of the
second chip taught in Miller because it would allow for reducing the number
of chips in the device of Miller. Final Act. 10-14.
With regard to Miller, Appellant disagrees with the
Examiner's characterization of Miller. Appellant states that the layer
thicknesses in Miller are chosen such that the two gain regions of the chips
have overlap to form a gain curve with a broader continuous band of
wavelengths. Miller, Figures 2 and 3. Appeal Br. 6. Appellant states that
this is a key feature of the device of Miller. Id. Appellant states that to
provide the enhanced gain in the region of the overlap, both chips must be
lasing since the combined gain curve shown at 62 (shown in Figures 2 & 3)
is higher than either of the two individual gain curves in the region of
overlap. Id. Column 1, lines 44-54 of Miller are reproduced below:
Specifically, an injection laser fabricated in accordance with the
present application comprises a laser cavity having first and second
active laser regions disposed in tandem therein, means for injecting
current into the first and second active laser regions to provide gain
distributions over wavelength regions in the two active laser regions
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Application 14/814,426
which partially overlay to form a combined gain distribution over a
range of wavelengths, and means for providing wavelength selective
loss for radiation having a wavelength within that range.
Appeal Br. 6.
Hence, Appellant submits that the chips in Miller both support lasing
when the output of the laser is at wavelengths in the overlapping region. We
agree.
With regard to Berger, Appellant argues that the laser of Berger is
designed to lase at two different wavelengths at the same time. Berger, col.
2, line 57 to col. 3, line 9. Appeal B. 7. Appellant states that therefore the
active layers must support lasing at two different wavelengths. Accordingly,
Appellant submits that Berger does not provide the missing teachings of
Miller. More specifically, Appellant submits that the Examiner has not
pointed to any teaching in the references that the quantum well thicknesses
of sub-layers are chosen such that only one of three sub-layers supports
lasing at any given electrical bias of the first and second gain chips. Appeal
Br. 7. Appellant states that the Examiner attempts to overcome this lack of
teaching by arguing that the external cavities or wavelength filters associated
with the gain chips limit the operation to one wavelength, and hence, the
sub-layers must have this property. Appeal Br. 7.
Appellant argues that the limitation relates to supporting lasing, not to
lasing at a single wavelength. Appeal Br. 7. Appellant explains that the
gain profile of the chips is such that two or more of the active regions would
support lasing if the cavity or wavelength filter was set to some particular
wavelength. Appellant states that the device of Miller presumably only lases
at one wavelength at a time; however, each of the gain chips support
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lasing over a broad band of wavelengths. Appellant states that, as noted
above, the fundamental principle of Miller is that the gain chips have
overlapping gain profiles so that the combined gain chip has gain over the
entire band spanned by the two gain chips. Appellant states that the
principle is realized by having two gain chips that support lasing over the
same sub-band of wavelengths and are both providing that gain over the
band between the peaks of the individual gain curves. Appeal Br. 7.
Appellant submits therefore that the Examiner has not pointed to any
teaching that a single gain chip having an active layer with the three sub-
layers would support simultaneous lasing by two of the first, second, and
third sub-layers. Appeal Br. 7.
In response, the Examiner argues that the limitations of claim 1 ( as
well as claim 10) are satisfied if there exists a single bias at which only one
of the first, second, and third sub-layers supports lasing at any given
electrical biases of the first and second chips, but that if all three sub-layers
were contained in a single chip, the sub-layers would support simultaneous
lasing of two of the sub-layers. Ans. 5.
In reply, Appellant argues that the Examiner bases this position on
the assertion that the limitation could not be satisfied given the second
requirement that "a single gain chip having an active layer with said three
sub-layers would support simultaneous lasing by two of said first, second,
and third sub-layers" if the "at any given electrical biases" requires the
limitation to be true at all electrical biases. Reply Br. 1. Appellant states that
the Examiner bases this argument on the assumption that there will always
be a set of biases in which the two-chip embodiment of claim 1 would
support lasing at two different wavelengths, since there is a bias at which the
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single chip serially connected sub-layers support lasing at two different
wavelengths. Appellant states that this position rests on the assumption that
the only factor that causes the stacked one chip embodiment to support
lasing at two wavelengths is the bias current through the sub-layers.
However, Appellant explains that, as pointed out at
paragraphs [0023]-[0024] of the Specification, the situation in which two
different sub-layers can support lasing at the same time arises from the serial
connection between the sub-layers and changes in gain of the dominant sub-
layer brought about by a reduction in the population inversion of that sub-
layer when that sub-layer starts to lase. Reply Br. 2.
Appellant also explains that as noted in paragraph [0031] of the
Specification, the present application overcomes this problem by moving
one of the sub-layers to a second chip. Reply Br. 2. Appellant asks that we
consider a case in which the three different sub-layers are on one chip and
there is a bias at which two of the sub-layers simultaneously support lasing.
In such a case, Appellant states that by reconfiguring the laser to have two
gain chips in which one of the two layers is now moved to a second chip, the
layer on the second chip is no longer available to lase when the gain of the
other sub-layer is reduced as the current is increased in the first chip. Id.
Appellant further states that the Examiner asserts that if there is a bias
at which a three sub-layer system will support lasing at two different
wavelengths because two of the sub-layers support lasing when biased with
the same current, then there will necessarily be a bias condition in which two
of the sub-layers will support lasing if one of the problematic sub-layers is
moved to a second chip. Reply Br. 2. However, Appellant submits that the
Examiner does not point to any such teaching in the art; hence, Appellant
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assumes that the Examiner is arguing that it is inherent that such a bias
condition exists. Appellant argues that the Examiner's argument assumes
that the only factor determining when a chip supports lasing is the bias
current through the chip and the band pass of the external cavity. Reply Br.
2.
Appellant further states that as pointed out in paragraph [0024] of the
Specification, the second sub-stack in the serially connected active layer
chip supports lasing even though the external cavity is tuned to block such
lasing because the facets of the gain chip form a second non-tunable cavity.
Reply Br. 2. Appellant states that it is the combination of the gain chip and
the facet cavity that causes the problem. Id. Appellant states that
accordingly, if the second gain chip does not have significant reflection on
the cavity closest to the external cavity reflector, there will not be sufficient
gain to lase at wavelengths that are only compatible with the facet cavity no
matter what the bias current. Reply Br. 2-3. In such a case, Appellant states
that the external cavity determines which sub-layer lases. Accordingly,
Appellant submits that it is not inherent that there is a bias condition in
which two sub-layer sublayers simultaneously support lasing. Reply Br. 2-
3.
We are persuaded by the aforementioned arguments. Because the
Examiner's position is based in part on faulty or unsupported assumptions
(as discussed, supra), we reverse Rejection 1. Since the additionally applied
reference of Rejection 2 is not relied upon by the Examiner to cure the
aforementioned deficiencies, we also reverse Rejection 2.
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Each rejection is reversed.
DECISION
ORDER
REVERSED
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