from the United States Patent and Trademark Office, Patent
Trial and Appeal Board in No. 95/001, 175.
L. McCombs, Haynes & Boone, LLP, Dallas, TX, argued for
appellant. Also represented by Debra Janece McComas; Gregory
P. Huh, Julie Marie NICKOLS, Richardson, TX.
N. Fahmi, Ascenda Law Group, PC, San Jose, CA, argued for
Prost, Chief Judge, Wallach and Chen, Circuit Judges.
case arises from Cisco Systems, Inc.'s (Cisco) request
for inter partes reexamination before the U.S.
Patent and Trademark Office of all claims of U.S. Patent No.
6, 415, 082 ('082 patent), which is owned by Cirrex
Systems, Inc. (Cirrex). The '082 patent originally issued
with claims 1-34, and Cirrex added claims 35-124 during
reexamination and subsequently amended and canceled several
original claims. As relevant here, the Examiner found
claims 56, 57, 76, 102, and 103 patentable and rejected
claims 38-41, 43-47, 49-50, 58-61, 75, 84-87, 89-93, 95-96,
104-107, and 121 for lack of written description support. The
Board affirmed. Cisco Sys., Inc. v. Graywire LLC,
No. 2012-006121, 2013 WL 4782204 (P.T.A.B. Sept. 5, 2013).
appeals the Board's patentability finding for claims 56,
57, 76, 102, and 103, and Cirrex cross-appeals the
Board's rejections. Because all the claims on appeal are
unpatentable for lack of written description support, we
affirm, in part, and reverse, in part.
'082 patent is directed to the field of fiber optic
communication signals. '082 patent col. 1 ll. 14-15.
Fiber optic communication signals use light energy made up of
multiple different wavelengths within one fiber optic cable,
and it can be useful to separate an optical beam into its
individual wavelength components to allow a logical operation
to be performed selectively on a particular wavelength, such
as adding or deleting, or changing the intensity of, the data
signal carried on each specific wavelength. The "single
optical beam" comprises several different wavelengths,
which "can include separate information channels that
are carried by a first optical beam" having one
particular wavelength and "a second optical beam"
having a second particular wavelength. Id. col. 1
ll. 40-50. "In other words, multiple channels of
information can propagate along an optical waveguide as a
single beam of light energy." Id. col. 1 ll.
separate individual wavelengths from an optical beam, the
'082 patent describes an optical network assembly that
uses a planar lightguide circuit (PLC). Id. col. 1
ll. 14-17, 20-24, col. 2 1. 65-col. 3 1. 2, col. 4 ll. 10-36.
The PLC, together with a series of filtering devices, splits
the single, composite optical beam into multiple channels
based on individual wavelengths. Id. col. 4 ll.
10-22. The combination PLC and filtering device
"separate[s] the optical energy into at least two beams,
where a first beam can contain a first information channel
and a second beam can contain a second information
channel." Id. col. 2 ll. 50-53. The PLC is also
attached to external optical waveguides which direct the
beams of individual wavelengths of light away from and back
into the PLC. Id. col. 2 ll. 45-65. These external
optical waveguides can include amplifiers (which increase the
intensity of the light beam) and attenuators (which decrease
the intensity of the light beam) to create optical systems
that can perform equalization or discrete attenuation, and
diverting elements (which can divert or introduce a light
beam of a specific wavelength). Id. col. 4 ll.
10-60, col. 14 1. 58-col. 15 1. 40. The parties do not
dispute the technical features of beam splitting, amplifying,
or attenuating of light beams.
modify an individual wavelength of light, the '082 patent
describes using a "diverting element" (1000) out-
side the PLC to divert a light beam of wavelength lambda
three (λ3) and replace λ3
with a different light beam of wavelength
λ3', then adding
λ3' back into the PLC. This
"embodiment can function as an optical switch"
using a "diverting element. . . that diverts a channel
signal out of an optical circuit while introducing a new
signal content along the same channel into the optical
circuit." Id. col. 4 ll. 48-53. The "PLC
and filtering device combination can form a drop or add
configuration where one channel of information propagating
within a multichannel or multiplexed optical beam can be
either dropped from or added to the multichannel or
multiplexed beam." Id. col. 4 ll. 12-16. Figure
10 shows a cross-connect feedback loop that uses a diverting
element 1000 that diverts λ3 and introduces
fig. 10 (as annotated by Cisco). As shown in Figure 10, the
diverting element 1000 is a double-sided mirror. Id.
col. 14 ll. 7-9. Figure 11 shows the diverting element in the
"in" position, which diverts λ3
and introduces λ3'. Id. col.
14 ll. 47-52. Figure 12 shows the diverting element in the
"out" position, in which A3 is not diverted.
Id. col. 14 ll. 53-57.
of the illustrated cross-connect feedback loop allows a fiber
optic communication system to transmit multiple channels of
information on one fiber optic cable, without sacrificing the
ability to manipulate the information being transmitted along
each individual wavelength of light. Id. col. 1 ll.
25-30. This maximizes efficiency because multiple wavelengths
of information can be sent simultaneously rather than having
to be sent in seriatim. Id. col. 1 ll. 25-30.
(210E) itself is disclosed in more detail in Figure 7 of the
patent fig.7. Figure 7 shows an exemplary embodiment of PLC
210E containing a four-channel drop-add. The bottom left-hand
corner shows an optical beam input with optical energy of
introduced into PLC 210E. Id. col. 13 ll. 22-23.
Individual light wavelengths
λ1-λ4 are, in succession,
"dropped" by filtering out (i.e., beam
splitting) through the top of the PLC, and later
"reintroduced" through the bottom of the PLC.
Id. col. 13 ll. 24-26. As the optical beam transits
within the PLC, reflecting up and down in a zig-zag fashion,
the individual wavelengths-λ1,
λ2, λ3, and
λ4-are successively filtered out of the
optical beam, with each wavelength traveling through the top
of the PLC and then within its own individual optical
waveguide. Because PLC 210E is part of a feedback loop
circuit, Figure 7 shows how those individual wavelengths
λ3, and λ4 are ultimately
reintroduced through the bottom of PLC 210E.
way, PLC 210E demultiplexes incoming optical energy so that
individual wavelengths of light are separated and redirected
outside the PLC on a channel-by-channel basis before they are
returned to the PLC and remultiplexed together, after which
the remultiplexed optical energy exits PLC 210E through the
top right-hand corner. Id. col. 13 ll. 31-38. When
Figure 7 is considered in combination with Figures 10-12
above, the data signals carried by the individual wavelengths
of light that are returned to the bottom of PLC 210E can be
different from the data signals carried by the individual
wavelengths of light that originally exited the top of the
PLC, through the use of diverting elements.
way to modify an individual wavelength of light is shown in
Figure 13, which discloses using amplification or attenuation
material (1300) to increase or de- crease the intensity of an
individual wavelength of light before it is returned to the
PLC. As illustrated in Figure 13, and described in the
specification, the amplification or attenuation material is
located outside PLC 210E and is positioned within each
individual optical waveguide path.
fig.13. The '082 patent explains several ways in which
light energy can be amplified (such as by using a pump laser
light with an optical filtering device) or attenuated (such
as by using absorbing material of a certain length), and the
parties do not dispute the specifics of how the amplification
or attenuation is accomplished. Id. col. 15 ll.
9-43. One reason that light energy intensity for a specific
wavelength should be turned up or down is to improve
transmission of the beam, while reducing transmission losses,
as the beam travels over long distances or between multiple
destinations. Id. col. 3 ll. 2-9. This ability to
apply “selective” flattening or amplification to
"each channel" outside the PLC can be used to (1)
equalize the intensities of light across all channels, or (2)
"discretely attenuate" individual channels outside
the PLC, without attenuating all the channels at the same
time. Id. col. 4 ll. 56-60, col. 6 ll. 31-35, col.
15 ll. 8-10. The '082 specification does not disclose why
equalization of light energy across all channels is useful,
but it does disclose that amplification can vary dramatically
with the wavelength of light being amplified, and discrete
attenuation can counter this variation in amplification.
Id. col. 14 1. 59-col. 15 1. 5.
'082 specification further makes clear that
"discrete attenuation" is distinct from
In the assembly illustrated in FIG. 13, the channels
operating at wavelengths lambda one (Ai) through lambda four
(A4) are attenuated discretely by gain flattening elements
1300. . . .
The assembly illustrated in FIG. 13 supports a discrete
channel approach to signal amplification which is
different from the common approach of
collectively amplifying the channels. In the illustrated
embodiment, the elements 1300 depicted can be amplifiers that
apply selective gain to each spectral region. The spectral
regions may contain one or numerous channels.
Id. col. 14 1. 64-col. 15 1. 40 (emphases added). As
the '082 specification explains, the discrete approach to
attenuation or amplification is distinct from the collective
approach because each wavelength of light is separately
amplified or attenuated, whereas in the collective approach,
the same amplification or attenuation is applied to all
wavelengths of light in the same way. The '082
specification also briefly mentions that the attenuation
material can be positioned at various places in an optical
architectural assembly, including inside the zig-zag path of
PLC 210E, but it does not disclose how placing attenuation
material inside PLC 210E would result in the ...