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Fujitsu Limited v. Tellabs Operations

September 29, 2011

FUJITSU LIMITED, PLAINTIFF,
v.
TELLABS OPERATIONS, INC. AND ) TELLABS, INC., DEFENDANTS.
TELLABS OPERATIONS, INC. PLAINTIFF,
v.
FUJITSU LIMITED AND FUJITSU ) NETWORK COMMUNICATIONS, INC., DEFENDANTS.
FUJITSU LIMITED, COUNTER CLAIMANT,
v.
TELLABS OPERATIONS, INC., TELLABS, INC., AND TELLABS NORTH AMERICA, INC., COUNTER DEFENDANTS.



The opinion of the court was delivered by: James F. Holderman, Chief Judge:

Consolidated for Discovery

MEMORANDUM OPINION AND ORDER

On January 29, 2008, Fujitsu Limited filed a complaint against Tellabs, Inc. and Tellabs Operations, Inc. in the United States District Court for the Eastern District of Texas ("Texas Action") alleging infringement of U.S. Patent Nos. 5,526,163 ("'163 Patent"); 5,521,737 ("'737 Patent"); 5,386,418 ("'418 Patent"); and 6,487,686 ("'686 Patent").*fn1 (Case No. 09-4530, Dkt. No. 1, Fujitsu's Compl. ¶¶ 1, 12-35.) Tellabs Operations, Inc. then filed suit against Fujitsu Limited and Fujitsu Network Communications, Inc. (collectively "Fujitsu") in the United States District Court for the Northern District of Illinois ("Illinois Action") on June 11, 2008, alleging infringement of U.S. Patent No. 7,369,772 ("'772 Patent"). (Case No. 08-3379, Dkt. No. 1, Tellabs's Compl. ¶ 1.) Both Fujitsu Limited and Fujitsu Network Communications, Inc. filed their amended answers, affirmative defenses, and counterclaims in the Illinois Action on April 1, 2009. (Dkt. Nos. 119, 120.) In its counterclaims, Fujitsu Limited alleged that Tellabs Operations, Inc., Tellabs, Inc., and Tellabs North America (collectively "Tellabs") infringed two additional patents assigned to Fujitsu Limited: U.S. Patent Nos. 7,227,681 ("'681 Patent") and 5,533,006 ("'006 Patent"). (Dkt. No. 119.)

On May 13, 2009, this court issued its preliminary claim constructions of certain disputed claim terms in the '772, '681, and '006 Patents. (Case No. 08-3370, Dkt. No. 145 ("Prelim. Constr. Op.").) The Texas Action subsequently was transferred to the Northern District of Illinois on July 29, 2009, and the two cases were consolidated before this court for purposes of discovery. (Case No. 08-3379, Dkt. No. 202.) After the cases were consolidated, this court held a three-day technology tutorial related to the general technology underlying the six patents-in-suit.

The parties then identified additional claim terms for the court to construe and filed briefs related to those proposed constructions. Tellabs also filed two motions for summary judgment: Tellabs's "Motion for Summary Judgment of Invalidity Based on Indefiniteness of All Asserted Claims (1 and 6-9) of U.S. Patent No. 5,386,418" (Case No. 09-4530, Dkt. No. 165) and its "Motion for Summary Judgment of Invalidity Based on Indefiniteness of All Claims of U.S. Patent 5,533,006" (Case No. 08-3379, Dkt. No. 305). Fujitsu then filed its "Motion for Summary Judgment for Judicial Correction of 'And' to 'A' in Claim 1 of U.S. Patent 5,386,418" (Case No. 09-4530, Dkt. No. 202 ("Fujitsu's Mot.")). On November 30 and December 1, 2, 3, and 7, 2010, the court held a Markman hearing, during which the parties' counsel addressed the respective claim construction positions as well as parties' motions for summary judgment. The parties have presented the court with over 900 pages of demonstrative slides, nearly 400 pages of briefing, and a multitude of exhibits, addressing their respective claim construction positions.

On March 31, 2011, this court issued its Memorandum Opinion an Order denying Tellabs's "Motion for Summary Judgment of Invalidity Based on Indefiniteness of All Asserted Claims (1 and 6-9) of U.S. Patent No. 5,386,418" and granting Fujitsu's "Motion for Summary Judgment for Judicial Correction of 'And' to 'A' in Claim 1 of U.S. Patent 5,386,418." (Case No. 09-4530, Dkt. No. 305). That same day, the court issued its Memorandum Opinion and Order granting Tellabs's "Motion for Summary Judgment of Invalidity Based on Indefiniteness of All Claims of U.S. Patent 5,533,006." (Case No. 08-3379, Dkt. No. 369.)

The court now sets forth its constructions of the nineteen remaining disputed claim terms in the '418, '163, '737, '681, and '772 Patents.

LEGAL STANDARDS

Claim construction is a matter of law for the court. Markman v. Westview Instruments, Inc., 517 U.S. 370, 390-91 (1996). "It is a 'bedrock principle' of patent law that 'the claims of a patent define the invention to which the patentee is entitled the right to exclude.'" Phillips v. AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (quoting Innova/Pure Water, Inc. v. Safari Water Filtration Sys., Inc., 381 F.3d 1111, 1115 (Fed. Cir. 2004)). In construing a patent's claims, the court gives claim terms their "ordinary and customary meaning," which is "the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention." Id. at 1312-13. The ordinary and customary meaning of a claim term is determined in light of the entire intrinsic evidence, i.e., the claims, the specification, and the prosecution history. Id. at 1313-17. Usually, the specification "is the single best guide to the meaning of a disputed term." Id. at 1315 (citation omitted). However, "[t]here is a fine line between construing the claims in light of the specification and improperly importing a limitation from the specification into the claims," Retractable Techs., Inc. v. Becton, Case No. 2010-1402, 2011 WL 2652448, at *8 (Fed. Cir. July 8, 2011), and "[g]enerally, a claim is not limited to the embodiments described in the specification unless the patentee has demonstrated a 'clear intention' to limit the claim's scope with 'words or expressions of manifest exclusion or restriction.'" i4i Ltd. P'ship v. Microsoft Corp., 598 F.3d 831, 843 (Fed. Cir. 2010) (quoting Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 906 (Fed. Cir. 2004)).

The prosecution history also "provides evidence of how the PTO [U.S. Patent and Trademark Office] and the inventor understood the patent" and "can often inform the meaning of the claim language by demonstrating . . . whether the inventor limited the invention in the course of prosecution." Phillips, 415 F.3d at 1317. Nevertheless, "because the prosecution history represents an ongoing negotiation between the PTO and the applicant, rather than the final product of that negotiation, it often lacks the clarity of the specification and thus is less useful for claim construction purposes." Id.

Finally, the court can rely on extrinsic evidence such as "expert and inventor testimony, dictionaries, and learned treatises" in construing a patent's claims. Id. (citation omitted). Such extrinsic evidence "can shed useful light on the relevant art" but is "less significant than the intrinsic record in determining the legally operative meaning of claim language." Id. (citations omitted).

ANALYSIS

I. '418 Patent

A. Background

The '418 Patent is titled "Method for Synchronizing Synchronous Data Communication Network and Communication Device Used in the Synchronous Data Communication Network." It issued on January 31, 1995, and is assigned to Fujitsu Limited. The '418 Patent relates to synchronous data communication networks, including networks using fiber optics to transmit high-speed digital signals, such as those used in cable television transmissions.

The acronym "SONET" is one of the known high-speed networks that transmits large capacities of information and stands for "Synchronous Optical Network." (2/23/10 Tech. Tutorial Tr. 327:13-15; '418 Patent, col.1 ll.32-34.) The SONET system is comprised of various stations or nodes connected via lines for transmitting and receiving information. In a SONET system, information is transmitted in frames, and each frame is organized into bytes. The frame structure is two-dimensionally depicted in graphic form as a matrix containing three main areas:

(1) section overhead, (2) line overhead, and (3) synchronous payload envelop, which includes the transmitted customer data and a path overhead. (See 08-3379, Dkt. No. 263 ("Fujitsu's '006 and '418 Patent Tutorial") 15; 2/23/10 Tech. Tutorial Tr. 330:11-331:9; '418 Patent, Fig. 1 (depicting a frame matrix).) In the SONET system, a frame is transmitted row by row, one byte at a time, moving from the upper left corner of the frame to the lower right corner. (Fujitsu's '006 and '418 Patent Tutorial 16; 2/23/10 Tech. Tutorial Tr. 331:10-18.)

The rate of delivery for transmitting the frames is driven by a clock source, i.e. an oscillator, which could come from an external timing source, a clock from the incoming bit stream (i.e., line timing), or the station's own internal clock (i.e., internal timing). (Fujitsu's '006 and '418 Patent Tutorial 23; 2/23/10 Tech. Tutorial Tr. 335:15-24.) During the operation of the system, the availability of a clock source may change. (2/23/10 Tech. Tutorial Tr. 342:17.) The '418 Patent discloses the sending of a "flag bit data" between the stations in the SONET system to indicate whether a clock source is available. (Id. at 342:7-11.) In a SONET system, the flag bit data--also referred to in SONET as a "synchronous status message" or "SSM"--is carried in the frame line overhead, which includes the information used by the network that is invisible to the network's customers. (2/23/10 Tech. Tutorial Tr. 343:9-23; Fujitsu's '006 and '418 Tutorial 17, 27.)

According to the '418 Patent, an object of the invention is to provide a synchronizing method of a synchronous data communication network in which a plurality of synchronizing signal sources are provided in a data communication network and data communication is maintained upon an occurrence of a failure by efficiently switching among the synchronizing signal sources in response to the failure that occurred, as well as to provide a communication apparatus used in such a synchronous data communication network. '418 Patent, col.2 ll.45-54.

Independent claim 1 of the '418 Patent recites: A method of switching from one synchronizing signal source to another in a synchronous data communication network including a plurality of stations with at least one child station and at least one parent station connected to each other via lines, and a plurality of synchronizing signal sources provided for said stations, the method comprising, in combination, steps of:

(a) setting, in a signal transmitted via said lines and including synchronizing information related to one of said plurality of synchronized signal sources, a flag bit data indicative of whether or not timing of said one of the plurality of synchronizing signal sources related to said synchronizing information transmitted via said lines can be used as a synchronizing signal source on each station which receives said information transmitted via said lines;

(b) referring each station, from among said plurality of stations on the basis of said flag bit data, to a table provided in each said station for specifying an order of priority for selection of a synchronizing signal source, upon occurrence of a predetermined event in any of said plurality of synchronizing signal sources, and for selecting a synchronizing signal source; and

(c) switching each station from the currently selected synchronizing signal source to the synchronizing signal source selected in said step (b).

Id. at col.18 l.51-col.19 l.9 (emphasis added). Step (a) in claim 1 originally read "setting . . . and flag bit data," but was corrected by a PTO issued Certificate of Correction to instead read "setting . . . a flag bit data." This court performed the same correction in its March 31, 2011 Order. (Case No. 09-4530, Dkt. No. 305.)

B. Person of Ordinary Skill in the Art Based on the parties' proposals, the court finds that a person of ordinary skill in the art with respect to the '418 Patent had (1) at least four years of experience in synchronization techniques for synchronous optical networks, or (2) a Bachelor's degree in systems engineering or electrical engineering with at least two years of experience either in synchronization techniques for synchronous optical networks or in researching and designing components for synchronous optical networks.

C. Claim Constructions

The parties have identified the following three claim terms in the '418 Patent for the court's construction: "flag bit data" (claims 1, 6-9); "switching each station" (claim 1); and "table" (claim 1).*fn2

1. "flag bit data" (claims 1 & 6-9)

The term "flag bit data" appears in claims 1, 6-9 of the '418 Patent. Fujitsu's proposed construction of "flag bit data" is "a predetermined code occupying a fixed position in each frame and is provided in a predetermined position of the overhead (i.e., not the payload)." (Case No. 09-4530, Dkt. No.195 ("Fujitsu's Resp.") 47.) Tellabs, on the other hand, relies on the uncorrected phrase "and flag bit data" in claim 1 to contend that the term "flag bit data" is indefinite. (Case No. 09-4530, Dkt. No. 164 ("Tellabs's Op. Br.") 43.) As stated above, in its March 31, 2011 Order, this court corrected the phrase "and flag bit data" in claim 1 of the '418 Patent to read "a flag bit data." (See Case No. 09-4530, Dkt. No. 305.) As a result, the court finds that the term "flag bit data" is not indefinite. For the following reasons, this court adopts Fujitsu's proposed construction of the term "flag bit data" with minor alteration and construes "flag bit data" to mean "a predetermined code that occupies a fixed position in each frame and is provided in a predetermined position of the overhead (i.e. not the payload)."

The specification provides an express definition of "flag bit data" which is consistent with Fujitsu's proposed construction:

The flag bit data is defined such that it occupies a fixed position in each frame (for example, the aforementioned reserved bit Z1). Accordingly, each station separates the frame multiplexed line signal into frames so as to detect the flag bit data. Moreover, the flag bit data contains a predetermined code consisting, for example, of only "1's" or of only "0's." '418 Patent, col.17 ll.52-58 (emphasis added).

The specification additionally explains that the "Z1" bit referenced in the above excerpt is located in a defined position in the overhead of a frame:

A synchronizing bit data for transmitting the synchronizing signal and a flag bit data indicating availability/non-availability of the synchronizing signal are provided in a predetermined position of the overhead of the signal transmitted through the stations in the digital communication network of the present invention. For example, the aforementioned reserved byte Z1 may be used.

Id. at col.6 ll.11-18 (emphasis added).

Tellabs has not presented any arguments challenging Fujitsu's proposed construction, other than to argue that the term cannot be construed. The court finds that Fujitsu's construction is consistent with the intrinsic evidence, particularly the '418 Patent's specification. Consequently, the court construes the term "flag bit data" to mean "a predetermined code which occupies a fixed position in each frame and is provided in a predetermined position of the overhead (i.e. not the payload)."

2. "switching each station"(claim 1)

The claim term "switching each station" appears in step (c) of claim 1 of the '418 Patent: "(c) switching each station from the currently selected synchronizing signal source to the synchronizing signal source selected in said step (b)." Id. at col.19 ll.7-9. According to Fujitsu, "switching each station" means "switching each station which receives said information transmitted via said lines (as recited in step (a) of claim 1)." (Fujitsu's Resp. 38.) Tellabs, however, contends that the proper construction is "switching every station of the plurality of stations." (Tellabs's Op. Br. 41.) The parties' primary dispute as to this claim term centers around whether every station must switch its synchronizing signal source. As explained below, the court agrees with Fujitsu and construes the claim term "switching each station" to mean "switching each station which receives said information transmitted via said lines (as recited in step (a) of claim 1)."

Looking first to the claim language, the network described in claim 1 includes "a plurality of stations with at least one child station and at least one parent station." '418 Patent, col.18 ll.53-54. The claim term "each station" appears in steps (a), (b), and (c) of claim 1:

(a) setting . . . a flag bit data indicative of whether or not a timing of said one of the plurality of synchronizing signal sources related to said synchronizing information transmitted via said lines can be used as a synchronizing signal source on each station which receives said information transmitted via said lines;

(b) referring each station from among said plurality of stations on the basis of said flag bit data, to a table . . . ; and

(c) switching each station from the currently selected synchronizing signal source selected in said step (b).

Id. at col.18 l.58-col.2 l.9 (emphasis added).

Fujitsu argues that "each station" in step (c) refers to "each station" recited in step (a).

Tellabs, however, contends that the "each station" in step (c) refers to the "plurality of stations" recited in the preamble of claim 1 and thus requires the switching of "every station of the plurality of stations." The court agrees with Fujitsu's interpretation of claim 1 because the term "each station" appearing in step (c) clearly refers to "each stationwhich receives said information transmitted via said lines" recited in step (a) of claim 1. In other words, not every station in the network must switch its synchronizing signal source as Tellabs contends. Only the station or stations receiving the transmitted synchronizing information must switch because the term "switching each station" in step (c) refers only to those stations which receive the transmitted synchronizing information.

This interpretation of "switching each station" comports with the teachings of the specification. Although the specification does disclose embodiments where all the stations ultimately do switch their signal sources, see '418 Patent, Figs. 3-14 (disclosing first embodiment); Figs. 37-42 (disclosing fifth embodiment), the court finds that rather than limiting the claims, these embodiments instead merely illustrate the various ways in which the stations in a network system respond to the unavailability of different signal sources. Switching depends on which signal source becomes unavailable and where the available signal source is located in the system as well as the configuration of nodes in the system. For example, the unavailability of the parent station's external clock will affect the system differently than the unavailability of a signal source between two child stations. See id. at Figs. 4-19, 22-42.

Additionally, the specification draws a distinction between the station sending the flag bit data and the stations receiving that data:

The present invention allows the parent station A to send, during normal operation, a flag bit data S, indicating that the synchronizing signal thereof is available, to all of its neighboring stations, and to send, when there is a failure in the synchronizing signal source, a flag bit data *S indicating that the same signal is not available.

Id. at col.5 ll.21-27. After receiving the signal indicating the availability of the synchronizing signal source, "the child stations B, C, D selects [sic], from among the neighboring stations having their flag bit data indicating that their synchronizing signal is available, a station to receive the synchronizing signal from, the selection being based on the order of priority specified in the table." Id. at col.5 ll.29-34. The specification, therefore, distinguishes between the station sending the information (e.g., the parent station) and the stations receiving the information (e.g., the child stations), which are the stations that switch their synchronizing signal source if the flag bit data indicates that the current source is unavailable. In other words, not every station in the network receives the transmitted synchronizing information as recited in step (a) of claim 1, and consequently step (c)of claim 1 does not require every station to switch its synchronizing signal source. Based on the specification, the court finds that a person of ordinary skill would not understand that "switching each station," as recited in step (c) of claim 1 requires every station in the network to switch.

The parties have not identified anything in the prosecution history that supports their respective constructions. Yet, the court has considered Tellabs's additional arguments for requiring that every station of the plurality of stations switch its synchronizing signal source and finds that those arguments similarly lack merit. Consequently, based on the intrinsic evidence, the court finds that Fujitsu's proposed construction is consistent with the plain language of the claims and is confirmed by the teachings of the specification. To require that "every station" switch its signal source, as Tellabs proposes, would improperly import a limitation into the claims. The court, therefore, construes "switching each station" to mean "switching each station which receives said information transmitted via said lines (as recited in step (a) of claim 1)."

3. "table" (claim 1)

The claim term "table" appears in claim 1 of the '418 Patent. Fujitsu proposes that the court construe "table" to mean "a list of data stored in memory." (Fujitsu's Resp. 28.) Tellabs, however, contends that "table" is "a data structure containing stored data elements and corresponding labels or indices." (Tellabs's Op. Br. 38.) The parties' dispute on this term centers around whether the table must include labels or indices or could instead be a single column, such as a list. As explained below, the court construes "table" to mean "a list of data stored in memory."

Step (b) in claim 1 recites: [R]eferring each station, from among said plurality of stations on the basis of said flag bit data, to a table provided in each said station for specifying an order of priority for selection of a synchronizing signal source, upon occurrence of a predetermined event in any of said plurality of synchronizing signal sources, and for selecting a synchronizing signal source. '418 patent, col.18 l.67-col.19 l.6 (emphasis added). Based on the claim language, the stations rely on the table for "specifying an order of priority for selection of a synchronizing signal source" and "selecting a synchronizing signal source." Fujitsu argues that a list of data would fulfill these requirements. Tellabs, on the other hand, argues that a list alone "does not provide an order of priority." (Case No. 09-4530, Dkt. No. 220 ("Tellabs's Reply") 45.) Instead, accordingly to Tellabs, labels or indices are also necessary to prioritize the signal sources. (Id.) Tellabs further contends that the table must include "usage and availability labels" indicating whether a signal source is available to specify the order of priority for selection of a synchronizing source. (Id. at 46.) In other words, without labels identify the usage and availability of the signal source, the table does not assist in the selection of a synchronizing source.

The plain language of claim 1 explains that the "table"is used for "specifying an order of priority for selection of a synchronizing signal source" and "for selecting a synchronizing signal source." The claim does not expressly require that the "table" provide information regarding the availability and usage of the signal source and therefore does not support Tellabs's position that the "table"must include such labels or indices indicating the source's availability and usage. Moreover, the court agrees with Fujitsu that a single list without labels or indices specifies an order of priority, e.g., highest to lowest or first to last, as required by claim 1.

The specification similarly does not warrant a narrower construction of "table." First, the specification discloses embodiments where the selecting station references the tableonly to ascertain the order of priority--not the availability or usage of the synchronizing signal source--and then independently determines whether the signal is available:

FIG. 5 illustrates the second stage of a failure that follows the stage shown in FIG.

4. The station B, which has received the flag bit data *S from the adjacent station A to the E direction, refers to the order of priority specified in the table T-B and checks the station C to the W direction. Since, however, the flag bit data *S is detected again, the station B selects the internal synchronizing signal source INT and changes the flag bit data supplied to the station C, from S to *S. '418 Patent, col.7 ll.3-11. In this embodiment, station B does not rely on the table to determine the availability or usage of the signal source but rather "checks the station C to the W direction" to detect the flag bit data which indicates the availability of the source. Thus, one of ordinary skill, having reviewed the specification for the '418 Patent, would understand that the "table" need not include information identifying the availability and usage of the signal source.

Second, the specification depicts tables where the order of priority is identified by a list of synchronizing signal sources without corresponding labels or indices specifying the priority of those sources. For example, Figures 3-19 of the '418 Patent disclose tables where the order of priority of the signal source is conveyed simply by arranging the sources from top to bottom in the table. Although Tellabs is correct that these tables additionally include a first column that refers to the usage and availability of the signal source, as discussed above, the specification does not require that the table include such information.

The court has also considered that parties' proffered dictionary definitions to assist in determining the ordinary and customary meaning of "table" to a person of ordinary skill. "Dictionaries or comparable sources are often useful to assist in understanding the commonly understood meaning of words . . . ." Phillips, 415 F.3d at 1322. In this case, the court finds that the dictionary definitions provided by the parties further confirm that Tellabs's proposed construction of "table" is overly narrow.

For example, the McGraw-Hill Dictionary of Scientific and Technical Terms (4th ed. 1989), cited by Tellabs, defines a table as "[a] set of continuous, related items, each uniquely identified either by its relative position in the set or by some label." Id. (attached as Ex. 10 to Tellabs's Op. Br.). Similarly, The New IEEE Standard Dictionary of Electrical and Electronic Terms (5th ed. 1993), also cited by Tellabs, defines "table" as "[a] collection of data in which each item is uniquely identified by a label, by its position relative to other items, or by some other means." Id. (attached as Ex. 11 to Tellabs's Op. Br.). Neither of these definitions indicates that a table necessarily includes labels. Instead, based on these definitions, labels are one of multiple possibilities for organizing data in a table. In addition to labels, the data may be identified "by its position relative to other items" or "by its relative position in the set," both of which support Fujitsu's contention that the "table"could consist of a single column. Lastly, The Harper Collins Dictionary of Computer Terms (1991), cited by Fujitsu, defines "table" as "a list of data stored in memory." Id. at 236 (attached as Ex. B-3 to Fujitsu's Resp.).

Based on the above evidence, the court finds that it can ascertain the meaning of "table" to a person of ordinary skill without considering the additional extrinsic evidence presented by the parties. To a person of ordinary skill in the art at the time of the invention disclosed in the '418 Patent, the term "table," as used in the '418 Patent, is data stored in memory in the form of either one or multiple columns and does not necessarily include labels or indices. Consequently, the court adopts Fujitsu's proposed construction and construes "table" to mean "a list of data stored in memory."*fn3

III. '772 Patent

A. Background

The '772 patent was issued to Tellabs Operations, Inc. on May 6, 2008, and is titled "Optical Line Terminal Arrangement, Apparatus and Methods." Ornan A. Gerstel and Rajiv Ramaswami are the named inventors. The '772 Patent claims priority to non-provisional application 09/293,775, filed on April 19, 1999, and to provisional application 60/112,510, filed on December 14, 1998.

The '772 Patent is directed to various configurations of a wavelength division multiplexing ("WDM") optical add/drop multiplexing system that adds, drops, or passes through optical signals at corresponding wavelengths and to the related methods for adding, dropping, and passing through WDM optical signals. In a typical optical communication system, a number of stations or nodes transmit data to and receive data from adjacent nodes in the system using optical signals. (9/23/09 Tech. Tutorial Tr. 46:25-47:5.) According to the '772 Patent, the prior art WDM systems required all wavelengths "to pass through from a source optical node to a predetermined sink optical node."'772 Patent, col.1 ll.38-40. The invention disclosed in the '772 Patent purports to advance the prior art by "selectively pass[ing]-through" individual wavelengths or "add[ing] or drop[ing] individual wavelengths at selected optical nodes." Id. at col.1 ll.41-43 (emphasis added). At a basic level, in a WDM system like the one disclosed in the '772 Patent, multiple optical signals are generated, multiplexed (i.e., combined) to form an optical signal comprised of the individual optical signal channel wavelengths, transmitted, and then demultiplexed (i.e., separated) into individual channel wavelengths. (See Case No. 08-3379, Dkt. No. 204 ("Willner Tutorial") 24-26.) The demultiplexed wavelengths can be added to or dropped from the node or passed through the node depending on their ultimate destination in the network. (See id.)

The Abstract for the '772 Patent provides the following description of the invention:

A wavelength division multiplexed optical communication system including a first optical line interface optically coupled to a first transponder and an optical demultiplexer through which the first optical line interface is not optically coupled to the first transponder. The system also includes a second optical line interface and at least one switch. The switch is operable to optically couple the second optical line interface to (a) the first optical line interface through at least the optical demultiplexer, and alternatively (b) the second transponder. A method for an optical add/drop multiplexing system also is provided. '772 Patent, Abstract.

Independent claim 1 of the '772 Patent is representative of the asserted apparatus claims: A wavelength division multiplexed optical communication system comprising: a first optical line interface optically coupled to a first transponder; a first local port optically coupled to the first transponder; an optical demultiplexer through which the first optical line interface is not optically coupled to the first transponder; a second optical line interface; a second local port optically coupled to a second transponder; and at least one switch operable to optically couple the second optical line interface to (a) the first optical line interface through at least the optical demultiplexer, and alternatively (b) the second transponder.

Id. at col.7 ll.1-17 (emphasis added).

Independent claim 17 of the '772 Patent is representative of the asserted method claims: A method for an optical add/drop multiplexing system in a wavelength division multiplexed (WDM) optical network environment, comprising the steps of: establishing at least a first optical path extending from a first optical line interface of the system to a local transponder; establishing at least a second optical path that in a first state of the system extends from a local transponder to a second optical line interface of the system and is established by at least an optical switch, and in a second state of the system the second optical path alternatively extends from the first optical line interface to the second optical line interface and is established by at least both the optical switch and an optical demultiplexer through which the first optical path does not extend; in the first state of the system, communicating a wavelength along the second optical path to add the wavelength to a WDM signal the system transmits to a WDM network from the second optical line interface; and in the second state of the system, alternatively communicating along the second optical path a wavelength of a WDM signal received from a WDM network at the first optical line interface to optically pass the wavelength to a WDM signal the system transmits to a WDM network from the second optical line interface. Id. at col.9 l.58-col.10 l.17.

B. Status of Reexamination Proceedings

Fujitsu filed a Request for Inter Partes Reexamination of the '772 Patent with the PTO on July 2, 2009, and the PTO granted that request. (Case No. 08-3379, Dkt. No. 322 ("Tellabs's Resp.") 1.) During the inter partes reexamination proceedings, Tellabs cancelled claims 1 and 3-5, and on June 24, 2010, the PTO issued an Action Closing Prosecution which confirmed the patentability of claims 2 and 6-24 without amendment. (Id. at 2.) Fujitsu has appealed that decision to the PTO Board of Patent Appeals and Interferences, and the appeal remains pending. (Case No. 08-3379, Dkt. No. 423 ("Tellabs's Reexam Status") at 2.)

Fujitsu also filed a Request for Ex Parte Reexamination of the '772 Patent on December 9, 2009, which the PTO ultimately granted in part with respect to claims 14-16 of the '772 Patent. (Case No. 09-4530, Dkt No. 298 ("Fujitsu's Reexam Status") 2-3.) The PTO issued an Ex Parte Reexamination Certificate dated May 27, 2011, reflecting Tellabs's cancellation of claims 14-16 of the '772 Patent during reexamination. (See Tellabs's Reexam Status 2.) To date, claims 2, 6-13, and 17-24 of the '772 Patent remain pending before this court. In the court's discussion below, the court must refer to now-cancelled independent claim 1 because claim 2, which Tellabs still asserts against Fujitsu, depends from claim 1.

C. Person of Ordinary Skill in the Art

After extensively reviewing the record, the court has been unable to locate any proposed definition of a person of ordinary skill in the art of the '772 Patent proposed by Fujitsu. The court accordingly adopts Tellabs's proposed definition, which provides that one of ordinary skill "had at least a Master's degree in electrical engineering, or the equivalent, and two to five years of experience researching or designing optical communication systems and the components" for such systems. (Tellabs's Resp. 3.)

D. Claim Constructions

The parties have identified the following eight claim terms in the '772 Patent for the court's construction: "optical demultiplexer" (claims 2, 6-13 & 17-24); "optical line interface" (claims 2, 6-13 & 17-24); "optical demultiplexer through which the first optical line interface is not optically coupled to the first transponder" (claim 2 & 6-13) and "optical demultiplexer through which the first optical path does not extend" (claims 17-24); "transponder" (claims 2, 6-13 & 17-24); "local port" (claim 2); "modular card" (claims 11-13, 22 & 24); and "office/reside in the same office (claims 8 & 21)."*fn4

1. "optical demultiplexer" (claims 2, 6-13 & 17-24)

The claim term "optical demultiplexer" appears in claims 2, 6-13, and 17-24 of the '772 Patent. In its preliminary construction, this court construed the claim term "optical demultiplexer" to mean "a device that receives a plurality of wavelengths multiplexed together as an optical signal and outputs each of the plurality of wavelengths as at least one of the following:

(a) individual wavelengths, (b) bands of wavelengths or (c) a combination of bands and individual wavelengths." (Prelim. Constr. Op. 10.)

Fujitsu argues that the court should modify its previous construction to require that the optical demultiplexer receives its input on a single optical waveguide and that the optical signal input be comprised of N optical wavelength channels. Fujitsu accordingly proposed the following construction of "optical demultiplexer": "a device that receives a single optical waveguide carrying an optical signal having N optical wavelength channels and outputs the N wavelength channels on individual optical waveguides, where the device outputs each of the N wavelengths as at least one of the following: (a) individual wavelengths, (b) bands of wavelengths or (c) a combination of bands and individual wavelengths." (Case No. 08-3379, Dkt. No. 335 ("Fujitsu's Reply") 33 & n.65.)*fn5 This amendment to the court's preliminary construction, Fujitsu contends, reflects the ordinary and customary meaning of "optical demultiplexer" and to prevents the optical demultiplexer from reading on an optical multiplexer or a router, which are devices having multiple inputs. (Case No. 08-3379, Dkt. No. 298 ("Fujitsu's Op. Br.") 38-42.)

Tellabs, however, argues that these limitations in Fujitsu's construction are not supported by either the intrinsic or extrinsic evidence and improperly impose structural limitations on the term. (Tellabs's Resp. 21-22.) Tellabs instead submits that the court should maintain its preliminary construction with minor amendment: "a device that receives a plurality of wavelengths multiplexed together as an optical signal and outputs each of separates the plurality of wavelengths as into at least one of the following: (a) individual wavelengths, (b) bands of wavelengths or (c) a combination of bands and individual wavelengths." (Tellabs's Resp. 19.) According to Tellabs, with this minor modification, its proposed construction differentiates a "optical demultiplexer," which separates the wavelengths, from an optical multiplexer which combines the wavelengths. Having reviewed the parties' respective positions, the court modifies its construction of the term "optical demultiplexer" to mean:

A device that receives a single optical waveguide carrying an optical signal having N optical wavelength channels and outputs the N wavelength channels on individual optical waveguides, where the device outputs each of the N wavelengths as at least one of the following: (a) individual wavelengths, (b) bands of wavelengths or (c) a combination of bands and individual wavelengths.

The court's construction of "optical demultiplexer" requires the resolution of two primary issues: first, whether the optical demultiplexer has a single input; and second, whether that input must be a waveguide. First addressing the claims, the plain language of the claims does not reference the optical demultiplexer's input. The specification, however, illustrates that a person of ordinary skill would understand the "optical demultiplexer" to have a single waveguide input.

In the "Background of Invention" section, the '772 Patent explains that "[i]n a WDM system optical signal channels are generated, multiplexed to form an optical signal comprised of the individual optical signal channels, transmitted over a single waveguide, and demultiplexed such that each channel wavelength is individually routed to a designated receiver." '772 Patent, col.1 ll.29-34 (emphasis added). The specification also discloses that optical demultiplexer receiving the optical signals over a "single optical fiber," which is a type of waveguide. (See 12/3/10 Markman Tr.490:3-6 (recognizing that "waveguides" is broader than "optical fibers").) The following embodiment, for example, includes optical wavelengths on "a single optical fiber" being demultiplexed:

The OLT 2 has an input/output line interface 4 which is connected to an external fiber facility and transmits/receives an optical signal having N optical wavelengths, for example 32 wavelengths, on a single optical fiber which is multiplexed/demultiplexed by a multiplexer/demultiplexer 6, which outputs demultiplexed wavelengths λ1-λN on individual optical fibers. '772 Patent, col.2 ll.38-46; see also id. at col.3 ll.61-63; col.4 ll.16-20. Tellabs has not directed the court to any evidence in the specification that identifies a non-waveguide input for the demultiplexer.

This interpretation of the customary meaning of optical demultiplexer to a person of ordinary skill is also consistent with Optical Networks, a cited prior art reference that was co-authored by Dr. Rajiv Ramaswami, one of the named inventors of the '772 Patent. The parties agree that Optical Networks reflects the understanding of a person of ordinary skill at the time of the invention. (See Fujitsu's Op. Br. 39; Tellabs's Resp. 25.) Optical Networks explains that "[a] multiplexer combines signals at different wavelengths on its input ports onto a common output port, and a demultiplexer performs the opposite function." Optical Networks 90 (1st ed. 1998) (attached as Ex. A-5 to Fujitsu's Op. Br). Optical Networks also explains that the demultiplexer receives the multiple wavelengths on a single fiber in describing Figure 3.6: "A multiplexer, which combines multiple wavelengths into a single fiber. In the reverse direction, the same device acts as a demultiplexer to separate the different wavelengths." Optical Networks 116 (2d ed. 2002) (attached as Ex. B-13 to Fujitsu's Op. Br.). Additionally, as Tellabs admits, Optical Networks "clearly discloses at least one embodiment of an optical demultiplexer that employs waveguides, not optical fibers, for coupling optical signals to and from the optical demultiplexer." (Tellabs's Resp. 25 (emphasis added).)

The requirement that the demultiplexer include a single input on a waveguide is further supported by the Fiber Optics Standard Dictionary (1997), which was cited by the PTO during the reexamination of the '772 Patent. (Tellabs's Resp. 19 n.86.) The Fiber Optics Standard Dictionary defines "demultiplex" as "[t]he inverse of multiplex, i.e., to separate two or more signals, such as optical pulses, that previously were combined, i.e., were multiplexed, by a compatible multiplexer and transmitted over a single channel, such as a fiber optical channel, for subsequent demultiplexing." Fiber Optics Standard Dictionary 209 (3d ed. 1997) (emphasis added) ...


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