Ex Parte Liu et al

Patent Trial and Appeal Board

Jun 27, 2014

11525786 (P.T.A.B. Jun. 27, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte XIANG LIU and XING WEI
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Appeal 2012-001869
Application 11/525,786
Technology Center 2600
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Before STEVEN D.A. McCARTHY, BRETT C. MARTIN, and
JENNIFER L. McKEOWN, Administrative Patent Judges.

McKEOWN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the Examiner’s final
rejection of claims 1-4, 6-8, 10-19, and 40- 43. App. Br. 2. Claims 5, 9, and
20-39 are indicated as allowable if rewritten. Final Rejection, dated Dec. 17,
2010, at 16. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

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Application 11/525,786

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STATEMENT OF THE CASE
Appellants’ invention relates to the reconstruction and restoration of
an optical signal field. Spec. p. 1, ll. 3-4. In particular, a digital version of
both amplitude and phase of a received optical signal is developed by
employing direct differential detection in conjunction with digital signal
processing. See Abstract.
Claim 1 is illustrative and is reproduced below, with the key disputed
limitation emphasized:
1. An optical receiver, comprising
a direct differential detection receiver, said direct
differential detection receiver receiving an incoming
optical signal as an input and supplying as an output
analog representations of real and imaginary parts of a
complex waveform that contains information about phase
differences between a plurality of time locations in said
incoming optical signal that are spaced by a prescribed
amount; and
a signal processor, coupled to said direct
differential detection receiver, for developing a digital
representation of an intensity and a phase profile
representing said incoming optical signal.

THE REJECTIONS
The Examiner rejected claims 1, 40, and 42 under 35 U.S.C. § 103(a)
as unpatentable over Epworth et al. (US 2004/0218932 A1; published Nov.
4, 2004). Ans. 5-7.
The Examiner rejected claims 1, 14, and 17 under 35 U.S.C. § 103(a)
as unpatentable over Epworth and F. Hargrave, HARGRAVE’S
COMMUNICATIONS DICTIONARY (Wiley—IEEE Press 2001) (“Hargrave”).
Ans. 7-8.
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The Examiner rejected claims 2 and 43 under 35 U.S.C. § 103(a) as
unpatentable over Epworth, Hargrave and Taylor et al. (US 2004/0114939
A1; published June 17, 2004). Ans. 8-9.
The Examiner rejected claims 3 and 4 under 35 U.S.C. § 103(a) as
unpatentable over Epworth, Hargrave and Qian (US 2007/0060077 A1; filed
Nov. 15, 2004). Ans. 10-11.
The Examiner rejected claims 6 and 7 under 35 U.S.C. § 103(a) as
unpatentable over Epworth, Hargrave and Giles et al. (US 2005/0069329
A1; published Mar. 31, 2005). Ans. 11-12.
The Examiner rejected claims 8 and 11-13 under 35 U.S.C. § 103(a)
as unpatentable over Epworth, Hargrave and Smith (US 7,003,120 B1; Feb.
21, 2006). Ans. 12-14.
The Examiner rejected claim 10 under 35 U.S.C. § 103(a) as
unpatentable over Epworth, Hargrave, Smith and Maltsev et al. (US
2005/0141406 A1; June 30, 2005). Ans. 14-15.
The Examiner rejected claims 15, 16, 18, 19 and 41 under 35 U.S.C.
§ 103(a) as unpatentable over Epworth, Hargrave and Nazarathy et al. (US
2008/0025733 A1; filed June 27, 2006). Ans. 15-17.

THE OBVIOUSNESS REJECTION BASED ON EPWORTH
The Examiner finds that Epworth teaches the claimed direct
differential detection receiver, but notes that Epworth does not explicitly
disclose a signal processor coupled to said direct differential detection
receiver. Ans. 5-7. The Examiner, however, relies on the teachings of
Epworth to demonstrate that these features of the claim limitation would
have been obvious to a skilled artisan. Id.
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Application 11/525,786

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The Appellants on the other hand contend that Epworth fails to
develop a digital representation of an intensity profile and a phase profile
representing said incoming optical signal. App. Br. 7-11. Additionally, the
Appellants argue that Epworth only discloses complex numbers and
therefore “cannot be said to define either the real part or the imaginary party
[sic]” of an input optical signal. App. Br. 11-12.

ISSUES
Under § 103, has the Examiner erred by finding that Epworth teaches
a signal processor, coupled to said direct differential detection receiver, for
developing a digital representation of an intensity and a phase profile
representing said incoming optical signal as recited in claim 1?

ANALYSIS
Claims 1, 40, and 42
Based on the record before us, we find no error in the Examiner’s
obviousness rejection of exemplary claim 1.
The Appellants first argue that Epworth fails to teach a phase profile.
App. Br. 7-11. Specifically, the Appellants assert that Epworth “cannot
develop the actual differential phase of the incoming optical signal.” App.
Br. 7. According to the Appellants, Epworth only develops the sine function
of the differential phase and this cannot sufficiently determine the actual
differential phase because the sine function is ambiguous. App. Br. 7-8.
Moreover, the Appellants assert that the “applicants are claiming knowing
absolutely the phase of the signal so that they can recover the whole optical
signal field.” App. Br. 8.
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We find these arguments unpersuasive. In particular, we agree with
the Examiner that the Appellants’ arguments rely on unrecited limitations.
See Ans. 18-19. Notably, as the Examiner points out, claim 1 does not recite
developing the “actual differential phase” or “knowing absolutely the phase”
but merely requires developing a digital representation of a phase profile
representing the incoming optical signal. Ans. 18. The Examiner expressly
outlines how under the broadest reasonable interpretation, Epworth’s sine
function, particularly with Epworth’s use of DPSK format, satisfies the
claimed phase profile. See Ans. 18-19. The Appellants fail to persuasively
respond to these findings.
Additionally, the Appellants maintain that Epworth fails to teach an
intensity profile because “at best, Epworth et al. develops the average value
of the power at time t and t-τ.” App. Br. 11 (citing Epworth ¶78,
Equation 8). However, as the Examiner points out, under the broadest
reasonable interpretation, the average intensity value plotted over time
would result in an intensity profile. Ans. 19-20. We agree then with the
Examiner that Epworth teaches developing the claimed intensity and phase
profiles.
Finally, the Appellants contend that the claimed “real or imaginary
part of an input optical signal should be a real number” and Epworth uses
“complex numbers.” App. Br. 11. This argument lacks merit. Epworth’s
cited equations (4 and 5) are formulas used to calculate real numbers. See
Epworth, Equations 4 and 5. Similar to the example provided by the
Appellants, Equation 5 represents the imaginary part by multiplying the
calculated number by j. Compare App. Br. 12 with Epworth, Equation 5.
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Accordingly, we are not persuaded that the Examiner erred in
rejecting claim 1 and independent claims 40 and 42, which are not argued
with particularity.

THE REMAINING OBVIOUSNESS REJECTIONS
Claims 1-4, 6-8, 10-19, and 40- 43
Because the Appellants rely on the same arguments with respect to the
remaining claims (App. Br. 13), we also are not persuaded that the Examiner
erred in rejecting claims 1-4, 6-8, 10-19, and 40- 43 (Ans. 7-17) for the
reasons noted above.

CONCLUSION
The Examiner did not err in rejecting claims 1-4, 6-8, 10-19, and 40-
43 under § 103.

DECISION
The Examiner’s decision rejecting claims 1-4, 6-8, 10-19, and 40-43
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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