Pirelli Cable Corp. v. Ciena Corp., CIV. A. No. 96-625 MMS.

• Decision Date: 17 November 1997
• Docket Number: CIV. A. No. 96-625 MMS.
• Citation: 988 F.Supp. 424
• Parties: PIRELLI CABLE CORPORATION, Plaintiff, v. CIENA CORPORATION, Defendant. CIENA CORPORATION, Counterclaim Plaintiff, v. PIRELLI CABLE CORPORATION, Pirelli S.p.A., and Pirella Cavi S.p.A., Counterclaim Defendants.
• Court: U.S. District Court — District of Delaware

988 F.Supp. 424

PIRELLI CABLE CORPORATION, Plaintiff, v. CIENA CORPORATION, Defendant.

CIENA CORPORATION, Counterclaim Plaintiff, v. PIRELLI CABLE CORPORATION, Pirelli S.p.A., and Pirella Cavi S.p.A., Counterclaim Defendants.

CIV. A. No. 96-625 MMS.

United States District Court, D. Delaware.

November 17, 1997.

Opinion Granting Reargument in Part February 18, 1998.

COPYRIGHT MATERIAL OMITTED

COPYRIGHT MATERIAL OMITTED

Robert W. Whetzel, Francis DiGiovanni, Richards, Layton & Finger, Wilmington, DE (Michael A. Epstein, Alan J. Weinschel, Steven D. Glazer, Daniel A. DeVito, Weil, Gotshal & Manges LLP, New York, NY, of counsel), for plaintiff and counterclaim defendants.

Jack B. Blumenfeld, Morris, Nichols, Arsht & Tunnell (Albert E. Fey, W. Edward Bailey, A. Peter Adler, Fish & Neave, New York, NY, of counsel), for defendant and counterclaim plaintiff.

OPINION

MURRAY M. SCHWARTZ, Senior District Judge.

I. INTRODUCTION

Pirelli Cable Corporation ("Pirelli") filed a complaint against Ciena Corporation ("Ciena") alleging infringement of five of its United States Patents concerning fiber optic technology. See Docket Item ("D.I.") 1, at ¶ 1. Ciena answered Pirelli's complaint and brought a counterclaim for a declaratory judgment that the patents in suit are invalid and not infringed by Ciena, and joined Counter Defendants Pirelli S.p.A., Pirelli Cavi S.p.A. and Pirelli General plc. D.I. 9, at ¶ 19.¹ Subsequently, two of the patents in suit, U.S. Patent No. 5,282,079 and U.S. Patent No. 5,355,250, have been dismissed. The remaining patents are U.S. Patent No. 5,113,459 ("the '459 Patent"), U.S. Patent No. 5,267,073 ("the '073 Patent"), and U.S. Patent No. 5,278,686 ("the '686 Patent").

Pursuant to Markman v. Westview Instruments, Inc., 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996), the Court scheduled briefing and oral argument for purposes of construing the disputed claim language of these three remaining patents in suit. The Court's construction of the disputed claim language follows.

II. FACTUAL BACKGROUND

Telecommunications is an important part of the global infrastructure of the Information Age. Communication by wire remains an important part of that infrastructure. The three patents remaining in suit relate to a specific type of telecommunications technology, "fiber optic telecommunications". Initially, telephone companies used copper wires to transmit electrical signals. However, the need for a more efficient method of transmitting telecommunication signals arose with the rise of the personal computer and associated modem, fax and Internet technologies. Because copper wire is limited in its ability and capacity to carry high speed communications, telecommunications companies turned to ultra-thin strands of ultra-pure glass, or "optical fibers," which have a higher capacity and are a faster transport medium than copper.

In an optical fiber telecommunication system, information is carried by an optical, light signal rather than an electrical signal. Because much of the world's telecommunication systems run on the old copper wires that carry electrical signals, the electrical signals must be converted to optical signals by an optical transmitter, which is usually a laser. The laser works by converting these electrical signals into light pulses of a certain wavelength that carry the encoded information down the optical fiber. At the other end of an optical fiber, the optical signals are then reconverted back into electrical signals by a photo detector, where they then can travel to individual telephones, computers, etc.

However, as optical signals travel down an optical fiber, the signal fades. As a result, optical amplifiers must be added to the line every so often so that the signal strength is maintained. Different optical signals can travel different distances down an optical fiber before fading depending on the optical signal's wavelength. This characteristic of the optical fiber is referred to as "attenuation". The lower the attenuation, the farther the optical signal can travel; the higher the attenuation, the shorter the distance.

Silica gel fiber, of which fiber optic lines are made, have a particular attenuation curve which allow certain optical wavelengths to travel further before fading. Those portions of the curve where the attenuation is relatively low, compared to proximate regions of the attenuation curve, are referred to as "silica gel attenuation windows". These windows represent those wavelengths at which the attenuation characteristics are most favorable in allowing the optical signals to travel the furthest. There are three such windows on the silica gel attenuation curve.

One way that optical amplifiers can operate is by seasoning or doping the fiber inside an amplifier with the rare-earth element, erbium. An erbium-doped fiber amplifier ("EDFA") works by producing an exact but amplified replica of the incoming light signals, which include the information encoded on them. However, these EDFAs are not compatible with the existing line terminal equipment (LTE), which collects transmitted electrical information signals and converts them to optical signals that can then be sent over the long-distance fiber optic system. The heart of the problem is that LTEs and EDFAs operate on different wavelengths. When a LTE sends out a light signal of a certain wavelength it cannot be properly amplified by the EDFA operating at a different wavelength. As a result, the signal would fade before it arrived at its terminal point.

In addition to the EDFA compatibility problem, increased demand since the time of the development of fiber optic cables has forced telecommunication companies to find a method to squeeze more capacity from their existing optical strands. The way that they eventually increased capacity was through a process called wavelength-division multiplexing ("WDM"). Instead of sending one information-encoded light signal over an optical fiber, WDM operates by combining several encoded light signals into one composite signal and then sending the resulting composite signal over the optical fiber. This process vastly increases the amount of optical signals that can travel down the line at any one time thereby increasing the capacity of the telecommunication system. In addition, telecommunication companies have used WDM to send both optical communication signals and optical service signals, which help monitor the proper functioning of the system, down the fiber optic line simultaneously.

However, the WDM process did not solve the incompatibility between the LTEs and the EDFA amplifiers. The three patents in suit involve technology that both makes LTEs compatible with EDFA amplifiers and advancements related to this new fiber optic technology. These advances allow telecommunication companies to send optical signals further distances, while monitoring the system and protecting maintenance personnel from injury.

The '459 Patent

Whereas normal communication signals for telephones, personal computers, faxes, etc., use optical light signals at a given wavelength, optical signals of another wavelength are used to carry service signals. In fiber optical communications systems that use EDFA optical amplifiers, there is no break in the optical fiber whereby optical service signals can be taken out of the cable and transformed into electrical signals. Optical service signals must be extracted and converted into electrical signals because the monitoring system can only read electric signals. In addition, these electrical signals need to be separately amplified so that when they are reinjected into the fiber optic line down-stream from the EDFA amplifier, they are at the same amplitude as the optical communication signals. Further, the utilization of electrical signals must be done without disturbing the on-going optical communication signals that are associated with the optical service signals.

The problem that the '459 Patent solves is devising a process which is able to separate the optical service signal from the optical communications signal without disturbing the transmission of the communications signal. The '459 invention developed a process which utilizes a device, an optical coupler, which is able to separate the optical service signals from the optical communication signals along different points on the line so that the optical service signal may be converted to an electrical signal. The optical coupler per se is not the invention claimed under the '459 Patent. Optical couplers were known devices before this patent issued. What is patented under this invention is the process by which optical service signals are separated from optical communication signals so that they can be converted into electrical signals and, thereafter, be amplified and monitored without disturbing the corresponding optical communication signal.

The parties' claim construction dispute is two-fold. First, whether the optical communication signal and the optical service signal wavelengths must be substantially different or just sufficiently different so that the optical coupler can separate the two signals. Second, whether the optical coupler must have three ports with the following characteristics: one input, one output, and one bidirectional input/output.

The '073 Patent

Because EDFA optical amplifiers are incompatible with LTEs, the '073 Patent describes a system in which adapters are inserted between the LTE and the amplifier in order to bridge this incompatibility. The invention operates by having an adapter at the sending terminal convert the signal produced by the transmitter to a signal having the parameters appropriate for the EDFA optical amplifier. A second adapter at the receiving terminal then reconverts the signal into a signal with the parameters appropriate for the receiver.

There are currently two claim construction disputes between the parties concerning the '073 Patent. First, whether...