Luxtera, Inc.

Patent Trials and Appeals Board

Dec 17, 2020

2019005123 (P.T.A.B. Dec. 17, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
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
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/818,352 11/20/2017 Thierry Pinguet 1027615US18 (110681) 9601
62147 7590 12/17/2020
PATTERSON & SHERIDAN, LLP/CISC
24 GREENWAY PLAZA
SUITE 1600
HOUSTON, TX 77046-2472
EXAMINER
BARUA, PRANESH K
ART UNIT PAPER NUMBER
2637
NOTIFICATION DATE DELIVERY MODE
12/17/2020 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):
Cisco_Admin@pattersonsheridan.com
PAIR_eofficeaction@pattersonsheridan.com
PSDocketing@pattersonsheridan.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
_________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
_________________

Ex parte THIERRY PINGUET, SHERIF ABDALLA,
MARK PETERSON, and GIANLORENZO MASINI
_________________

Appeal 2019-005123
Application 15/818,352
Technology Center 2600
_________________

Before JASON V. MORGAN, DEBORAH KATZ, and
JON M. JURGOVAN, Administrative Patent Judges.

KATZ, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 seeks our review2, under 35 U.S.C. § 134(a), of the
Examiner’s decision to reject claims 1–20. We have jurisdiction under
35 U.S.C. § 6(b). We AFFIRM.

1 We use the word “Appellant” as defined in 37 C.F.R. § 1.42. Appellant
identifies the real party-in-interest as Luxtera, Inc. (Appeal Br. 2.)
2 We consider the Final Office Action issued June 28, 2018 (“Final Act.”),
the Appeal Brief filed December 18, 2018 (“Appeal Br.”), the Examiner’s
Answer issued on April 18, 2019 (“Ans.”), the Reply Brief filed June 18,
2019 (“Reply Br.”).
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Application 15/818,352

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Appellant’s Specification is directed to hybrid integration of optical
communication systems to address increasing bandwidth requirements,
while overcoming the impediments of signal attenuation and crosstalk that
occur with copper data channels. (See Spec. ¶¶ 4, 6.) The Specification
explains that the invention provides for hybrid integration of optical
communications systems. (See id. ¶ 17.) Specifically, the Specification
describes the invention as receiving one or more continuous wave (CW)
optical signals in a silicon photonics die from an external optical source,
processing the optical signals based on electrical signals received from
electrical dies via metal interconnects, generating a second electrical signal
based on the processed optical signal, and communicating the optical
signals. (See id. ¶¶ 17, 33.)
Appellant’s claim 1 is representative and recites:
A method for communication, the method comprising:
in an optical communication system comprising a silicon
photonics die and one or more electronics die bonded to said
silicon photonics die utilizing metal interconnects:
receiving a continuous wave (CW) non-modulated
optical signal in said silicon photonics die from an optical
source external to said silicon photonics die;
modulating said received CW non-modulated optical
signal in said silicon photonics die using a first electrical signal
received from said one or more electronics die via one or more
of said metal interconnects;
receiving a modulated optical signal in said silicon
photonics die;
generating a second electrical signal in said silicon
photonics die based on said received modulated optical signal;
and
communicating said second electrical signal to at least
one of said one or more electronics die via one or more of said
metal interconnects.
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(Appeal Br. 27.) Claims 11 and 20 are also independent and are drawn to
systems for communicating, rather than methods. (See Appeal Br. 29 and
31.)
The Examiner rejects claims 1, 3–5, 7–11, 13–15, and 17–19 as being
obvious under 35 U.S.C. § 103(a) over Binkert3 and Estes4 (Final Act. 2–9),
claims 2, 12, and 20 as being obvious over Binkert, Estes, and Colgan5 (id.
at 10–14), and claims 6 and 16 as being obvious over Binkert, Estes, and
Gunn6 (id. at 14–15).

Findings of Fact
1. Binkert teaches an optical communication system having a
silicon photonics die and one or more electronics dies that are bonded to the
silicon die with metal interconnects bonded to a silicon photonics die using
vias that can be metalized. (See Binkert ¶¶ 30, 34, Fig. 1; see Final Act. 3.)
2. Binkert teaches a method for communication wherein non-
modulated optical signals are received in a silicon photonics die from an
external optical source, such as a laser. (See Binkert ¶¶ 30, 48, Fig. 1; see
Final Act. 4.)
3. Binkert teaches receiving a modulated optical signal in the
silicon photonics die, generating a second electrical signal in the silicon
photonics die based on the received modulated optical signal, and

3 Binkert et al., US 2009/0103855 A1, published April 23, 2009.
4 Estes and Moddel, US 2006/0038168 A1, published February 23, 2006.
5 Colgan et al., US 2004/0241892 A1, published December 2, 2004.
6 Gunn III et al., US 2006/0008223 A1, published January 12, 2006.
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communicating the second electrical signal to at least one or more electronic
die via the metal interconnects. (See Binkert ¶¶ 44, 47, 50; see Final Act. 4.)
4. Binkert does not teach a laser generating a continuous wave
(CW) optical signal or teach modulating a received CW optical signal using
an electrical signal received from an electronics die through metal
interconnects. (See Final Act. 4.)
5. Estes teaches electrical circuitry for providing and transmitting
electrical signals. (See Estes abstract.)
6. Estes teaches receiving an external CW light source and feeding
it into a wave guide for a first electron tunneling device to produce a
modulated light. (See Estes ¶ 69; see Final Act. 4.)
7. Estes teaches receiving a non-modulated CW signal and
modulating it with an electronic tunneling device to provide a modulated
light output. (See Estes ¶ 101; see Final Act. 4.)

Analysis
The Examiner finds that even though Binkert does not expressly teach
receiving and modulating a CW optical signal, Appellant’s claimed method
would have been obvious because it would have required only applying the
known technique of using a laser to emit a CW optical signal to a modulator,
as taught in Estes, in the communication method taught in Binkert. (See
Final Act. 5.)
Appellant argues that the prior art does not teach both CW non-
modulated and modulated optical signals in a method for communication.
(See Appeal Br. 12.) Specifically, Appellant argues that Binkert teaches
receiving a modulated optical signal, but not a CW non-modulated optical
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signal and that there would be no reason to add a non-modulated signal
when a modulated signal has already been received. (See id. at 12–13.)
Appellant cites to paragraph 36 of Binkert as teaching modulation
frequencies used to communicate data, arguing that non-modulated or CW
non-modulated optical signals would fail to achieve this goal because
modulated signals communicate data, whereas non-modulated signals do
not. (See id at 13.) Appellant continues by arguing that neither Binkert nor
Estes discloses how both a CW non-modulated optical signal and a
modulated optical signal would be integrated. (See id.)
We are not persuaded by these arguments because Binkert teaches
optical dies that include modulators and teaches that “[e]ncoding data into
unmodulated channels can be accomplished by modulating the intensity of
the channels.” (Binkert ¶¶ 47, 48; see Ans. 2.) Thus, although Binkert may
not expressly teach receiving a CW non-modulated signal, it demonstrates
that modulating optical signals are part of the communication method taught.
Appellant’s arguments are also unpersuasive because the Examiner
relies on the teaching in Estes to use a laser to transmit a CW optical signal
to a modulator that outputs a modulated optical signal. (See Ans. 2; see
Estes ¶ 101 (“when a continuous wave (CW) light input 592 is incident on
first chirped, focusing grating coupler 508', the array of electron tunneling
devices modulate the CW light input and, consequently, waveguide-coupled
assembly 500' provides a modulated light output 594.”). Thus, Estes teaches
modulating CW non-modulated optical signals, demonstrating that receiving
CW non-modulated optical signals in the method of Binkert would have
been obvious.
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Appellant acknowledges, “applying a CW optical signal to a
modulator does indeed result in a modulated signal . . . .” (Appeal Br. 13.)
But Appellant argues that Binkert would have disclosed the combination of a
modulator/modulated signal with a CW signal, in light of this general
understanding in the art and the teachings of Estes, if it had intended to
receive a CW non-modulated signal. (See Appeal Br. 13.) This argument is
unpersuasive because even if an aspect of a method is not expressly taught in
one prior art reference, it still may have been obvious. See KSR Int’l Co. v.
Teleflex Inc., 550 U.S. 398, 419 (2007) (“[i]n many fields it may be that
there is little discussion of obvious techniques or combinations, and it often
may be the case that market demand, rather than scientific literature, will
drive design trends.”). The absence of an express discussion of non-
modulated signals in Binkert does not persuade us that receiving such
signals at the onset of a method communication would not have been
obvious, particularly given the teachings of Estes and the discussions of
modulation in Binkert itself.
Furthermore, we are also not persuaded that the lack of an express
teaching in Binkert is a teaching away, as Appellant argues, given that
Appellant does not direct us to language in Binkert that would discourage
one from starting with a non-modulated signal or that indicates that non-
modified signals could not be part of a method as claimed. (See Appeal Br.
13.) See Syntex LLC v. Apotex, Inc. 407 F.3d 1371, 1380 (Fed. Cir. 2005)
(“What a reference teaches or suggests must be examined in the context of
the knowledge, skill, and reasoning ability of a skilled artisan. What a
reference teaches a person of ordinary skill is not, as Syntex's expert appears
to believe, limited to what a reference specifically ‘talks about’ or what is
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specifically ‘mentioned’ or ‘written’ in the reference. Under the proper legal
standard, a reference will teach away when it suggests that the developments
flowing from its disclosures are unlikely to produce the objective of the
applicant's invention.”)
Appellant argues further that a person of ordinary skill would not have
modified the system of Binkert with the specific terahertz interconnect
concept taught in Estes. (See Appeal Br. 13; see Reply Br. 5.) This
argument is unpersuasive because the Examiner’s rejection does not rely on
the specific “terahertz interconnect concept” taught in Estes, but rather that
Estes demonstrates those of ordinary skill in the art would have considered it
obvious to receive a CW non-modulated optical signal and to modulate it.
Appellant’s claim 1 does not recite a specific means of modulating the signal
and the structures of Estes need not have been bodily incorporated into the
method of Binkert for the claimed method to have been obvious. (See Ans.
3.) See In re Keller, 642 F.2d 413 (CCPA 1981) (“The test for obviousness
is not whether the features of a secondary reference may be bodily
incorporated into the structure of the primary reference; nor is it that the
claimed invention must be expressly suggested in any one or all of the
references. Rather, the test is what the combined teachings of the references
would have suggested to those of ordinary skill in the art.”). Appellant
argues further that the issue is “whether one would combine the CW laser of
Estes with the system of Binkert, which already discloses directly modulated
laser signals” (Reply Br. 6), but the Examiner’s rejection is not based on a
physical combination or replacement. Rather the rejection is based on the
knowledge in the art that optical signals could be CW optical signals
introduced into a system as non-modulated signals to be modulated therein.
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In the Reply Brief, Appellant argues that because Binkert already
teaches modulated optical signals, it would not have been obvious to one of
ordinary skill in the art to also receive CW optical source signals because it
would add cost and complexity. (See Reply Br. 2–4.) Appellant
misconstrues the Examiner’s rejection, which is not based on adding a signal
source to the method or system of Binkert. Instead, the Examiner cites Estes
to show that using a CW modulated signal in a communications method was
known at the time and that beginning with a CW non-modulated signal that
is then modulated was also known. The Examiner cites these teachings as
modifications and explanations of the method taught in Binkert, not
additions to it. (See Ans. 5.)
Appellant argues further that the Examiner fails to provide a sufficient
reasoning for combining the teachings of Binkert and Estes to arrive at the
claimed method. (See Appeal Br. 14–15.) We are not persuaded that the
Examiner erred because, again, the Examiner’s rejection is based on
modulating a CW signal, as taught in Estes, for use with a modulator, as
taught in Binkert, to generate an outgoing modulated optical signal. (See
Ans. 5.) The Examiner’s reasoning that using a laser emitting a CW signal
with the communication method taught in Binkert would have been obvious
because Binkert teaches lasers in general is reasonable. Appellant does not
provide a specific argument to the contrary.
Accordingly, Appellant fails to persuade us that the Examiner erred in
rejecting the method of claim 1 as being obvious over Binkert and Estes.
Appellant argues that the Examiner erred in rejecting independent
claims 11 and 20, which teaches a system for communication with elements
similar to those recited in claim 1, over Binkert and Estes for the same
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reasons argued against the rejection of claim 1. (See Appeal Br. 14, 15–16,
21–25.) Appellant argues further that the Examiner erred in rejecting
dependent claims 3–9 and 13–19 over Binkert and Estes for the same
reasons. (See id. at 17–21.) For the reasons explained above, we are not
persuaded that the Examiner erred rejecting any of these claims.
Appellant’s claims 2 and 12 depend on claim 1 and 11, respectively,
but require that the “metal interconnects comprise copper pillars.” (Appeal
Br. 27, 29.) The Examiner rejects these claims over Binkert, Estes, and
Colgan, citing Colgan for its teaching an integrated optical transducer
assembly with copper metal interconnects. (See Final Act. 10, Ans. 5; see
Colgan ¶ 19.) Appellant argues that Colgan does not teach copper pillars,
but only “interconnects” in Figure 1b, which are not explicitly discussed.
(See Appeal Br. 16.) Appellant acknowledges the teachings of bonded chips
in paragraph 19 of Colgan, but argues that this would teach using solder
balls, and therefore a lead alloy, instead of copper. (See id.) We are not
persuaded that the Examiner erred because Colgan teaches that “electrical
connection between components is achieved through copper. . . .” (Colgan
¶ 19 (emphasis added); see Ans. 5.) Furthermore, the Specification
describes that “the metal interconnects 207 may comprise copper pillars, or
any other suitable metal for semiconductor contacts, such as stud bumps or
solder bumps.” Spec. ¶ 30 (emphasis added). Thus, even if Appellant is
correct that Colgan discloses solder bumps, and not pillars, Appellant’s
Specification describes the two as equivalent for use as metal interconnects.
Appellant does not explain how the difference between the claimed pillars
and Colgan’s solder bumps renders the claims nonobvious, let alone explain
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how the claimed pillars are distinguishable from Binkert’s metallized vias.
Binkert ¶ 30.
Accordingly, we are not persuaded that the Examiner erred in
rejecting either claim 2 or 12.
Conclusion
Upon consideration of the record and for the reasons given, we affirm
the Examiner’s rejection.
In summary:
Claims
Rejected
35 U.S.C. § Basis/References Affirmed Reversed
1, 3–5, 7–11,
13–15, 17–19

103 Binkert, Estes 1, 3–5, 7–11,
13–15, 17–
19

2, 12, 20

103 Binkert, Estes,
Colgan
2, 12, 20

6, 16

103 Binkert, Estes,
Gunn
6, 16

Overall
Outcome
1–20

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136.

AFFIRMED