WO2003073656A1

WO2003073656A1 - Optical communication network

Info

Publication number: WO2003073656A1
Application number: PCT/US2003/003329
Authority: WO
Inventors: Allan G. Whittaker; Michael Gregory Abernathy; John Edward Mc Ginnis; Louis Milioti; John J. Soderberg
Original assignee: Lockheed Martin Corporation
Priority date: 2002-02-20
Filing date: 2003-02-05
Publication date: 2003-09-04
Also published as: AU2003217320A1

Abstract

Optical networks may be deployed within hospitals and other structures for permitting bi-directional optical communication. The networks include couplers that permit the network to branch out into multiple sub-networks and hubs. Each of these couplers functions as a junction box and can be used to couple with other networks, such as the Internet or other third party service providers, and can also be used to branch off signals off o main backbone. Furthermore, these couplers may be used to couple signals off of the backbone or a subnetwork toward a specific individual unit. The networks include bi-directional optical amplifiers which compensate for losses associated with the various couplers dispersed throughout the network.

Description

OPTICAL NETWORKS AND METHODS FOR USE IN HOSPITALS AND OTHER STRUCTURES

CROSS-REFERENCED TO RELATED APPLICATION

This application claims priority to U.S. Serial No. 10/079,677 filed on February 20, 2002 entitled "Optical Networks and Methods for Use in Hospitals and Other Structures," now pending.

FIELD OF THE INVENTION

The invention relates to optical networks and methods for use in structures and, more particularly, to networks, systems, and methods for permitting communication between units within a hospital and other structures.

BACKGROUND

Many, if not most, businesses today employ at least one type of network in their facilities. These networks include telephony networks, from simple wiring within the facilities for telephones sharing a common line to more sophisticated networks involving a Private Branch Exchange (PBX) and voice message servers. Another prevalent network is a computer network, such as a Local Area Network (LAN). A LAN serves to interconnect the various computers that may be used within the facility and are often deployed in a client- server configuration. Many such LANs have a number of servers for shared applications, for e-mail servers, and for files and documents. In addition to LANs, many businesses also employ Wide Area Networks (WAN) that serve to interconnect separate offices thereby facilitating inter-office communication and exchange of data. These LANs and WANs may also include connections to other networks, such as the Internet.

Businesses may have networks in addition to or instead of telephony and data networks. One example of such a network is an intercom system. The intercom system may have intercom units dispersed throughout the facility to allow personnel to easily communicate with each other. Another example of an alternative network is one that distributes video and/or audio throughout a facility. These networks would include coaxial cables or other wiring as well as the associated splitters, taps, and amplifiers.

One consequence of these various networks that may be deployed through a facility is that the facility must accommodate all of the wiring and other components of these networks. Often, a facility may have a dedicated room or groups of rooms that house the wiring and permit personnel to route the wiring throughout the facility. As can be appreciated by the number of networks a facility may have, the facility often has a considerable amount of space dedicated to such rooms. Because space within a facility is frequently a valuable commodity, these interconnect rooms present a substantial cost to the business.

In addition to the cost of the space itself, these networks are not easily installed and maintained. One reason for such a difficulty is that the various cables associated with the different networks, if not properly managed and organized, can render it extremely difficult for someone to differentiate the cables from the different networks and furthermore renders it difficult for someone to isolate a desired cable. As can be appreciated, any work that needs to be performed on any one network can be hampered by cabling problems.

Networks that are deployed in facilities commonly experience other problems, both alone and in the aggregate. For example, many networks in a facility are actually comprised of a number of separate sub-networks or hubs. These hubs or sub-networks need to be coupled to a backbone that runs throughout the facility. These sub-networks or hubs can be connected to the backbone in various ways, such as through switches or bridges. These couplers not only increase the cost of such networks but also degrade the overall performance of the networks.

SUMMARY

The invention addresses the problems above by providing structures having networks for optical communication. Networks according to the invention comprise a bi-directional optical bus for carrying optical signals between a plurality of units. Each unit is coupled to the optical bus through a passive optical coupler which directs optical signals traveling in either direction along the bus toward the unit and which impresses optical signals from the unit onto the optical bus in both directions simultaneously. The networks also include amplifiers that perform bi-directional amplification of the optical signals.

Networks according to the invention are suitable for use in hospitals, universities, office towers, residential buildings, government buildings, military bases, and other types of structures. The networks are immune to electromagnetic radiation since the units transmit and receive optical signals. The networks also present a low weight and lower complexity due to the use of a bi-directional optical bus rather than point-to-point connections. The networks can therefore significantly reduce the amount of cabling required within a structure. Furthermore, the networks according to the invention can accommodate large numbers of units, such as to 256 or more units.

The units connected to the optical bus can form part of multiple sub-networks or hubs and may comprise separate systems. For example, rather than separately installing and wiring telephony, data, and entertainment systems, structures equipped with networks according to the invention can integrate these systems onto a single backbone. These networks are easily expandable to accommodate additional units or even additional subnetworks or hubs.

Other advantages and features of the invention will be apparent from the description below, and from the accompanying papers forming this application.

BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention and, together with the description, disclose the principles of the invention. In the drawings: Figure 1 is a diagram of a structure equipped with a network according to a preferred embodiment of the invention;

Figure 2 is a circuit diagram of a Optical Interface Device forming part of the network of Figure 1; and

Figure 3 is an exemplary component diagram of the coupler of Figure 2.

DETAILED DESCRIPTION Reference will now be made in detail to preferred embodiments of the invention, non- limiting examples of which are illustrated in the accompanying drawings.

I. Overview

An example of a structure 20 equipped with a network 10 according to a preferred embodiment of the invention is shown in Figure 1. The structure 20 in this example is a hospital but can be comprised of other types of structures, including but not limited to office towers, multi-unit residential buildings, universities, colleges, and other schools, military bases, government buildings, or any structure that is equipped with one or more networks. The networks 10 include a number of units 12 which are joined to a bi-directional optical bus 14 through Optical Interface Devices (OIDs) 16. In order to minimize the number of wavelengths used on the bus 14, the networks 10 preferably employ only one wavelength, although the networks 10 may operate at more than one wavelength. The networks 10 may alternatively, or additionally, provide time divisional multiplexing access, such as described in co-pending U.S. patent application Serial No. 09/924,651, filed August 8, 2001, which is incorporated herein by reference.

The OIDs 16 may comprise any suitable structure for directing optical signals from each unit 12 onto the optical bus 14 in both directions and for directing optical signals traveling along the optical bus 14 in both directions toward each unit 12. A preferred OID is described in U.S. Patent Nos. 5,898,801 and 5,901,260, which are incorporated herein by reference.

The networks 10 according to the invention can carry any type of data, such as analog, digitized analog, digital, discrete, radio frequency, video, and audio signals. The units 12 can also operate under any media access, network, transport, session, presentation, or application protocol. These protocols include, but are not limited to, the Ethernet standard, as specified by International Standards Organization (ISO) 802.3, Mil-Std 1553, ARINC-429, RS-232, NTSC, RS-170, RS-422, NTSC, PAL, SECAM, AMPS, PCS, TCP/IP, frame relay, ATM, fiber channel, SONET, WAP, PCI, and InfiniBand. The units 12 may operate in accordance an encapsulation method described in co-pending U.S. patent application Serial No. 09/924,037 filed August 7, 2001, which is incorporated herein by reference.

Each unit 12 comprises an optical-to-electrical converter and may also include an electrical-to-optical converter. The electrical-to-optical and optical-to-electrical converters may be provided as part of an electro-optical interface circuit (EOIC) as described in U.S. Patent Nos. 5,898,801 and 5,901,260. The invention is not limited to the type of optical transmitter but includes LEDs and lasers, both externally and directly modulated. As will be appreciated by those skilled in the art, each unit 12 may also include translation logic devices and other devices used in the processing or routing of the signals. A preferred network is described in U.S. Patent No. 5,898,801 entitled "Optical Transport System," which is incorporated herein by reference.

The optical bus 14 is preferably a single-mode fiber that carries optical signals in both directions simultaneously to all units 12 connected to the bus 14. The optical bus 14 also preferably provides bi-directional optical amplification of the signals traveling along the bus, such as described in U.S. Patent Nos. 5,898,801 and 5,901,260. Thus, the amplification of the optical signals may occur along a section 14a of the bus 14 with section 14a forming at least part of the interconnection between two of the units 12. The optical amplification need not occur along the interconnection sections 14a but alternatively may be provided along paths 18 which interconnect the units 12 to OIDs 16. Furthermore, the optical amplification may occur within the units 12 or within the OIDs 16. The optical amplification may be performed through fiber amplifiers, such as erbium-doped fibers or other rare-earth doped fibers, as described in U.S. Patent Nos. 5,898,801 and 5,901,260. The amplification may also be performed by devices separate from the fiber, such as any of the various discrete laser amplifiers.

Significantly, the amplification that occurs within the network 10 associated with each unit 12 compensates for splitting losses to and from that unit 12. In other words as optical signals travel down the bi-directional optical bus 14 and encounter an OID 16, a fraction of the optical signals is diverted to the unit 12. To compensate for this loss in signal strength, the optical signals are amplified, such as up to their original level, to maintain signal quality and strength. Thus, when the signals arrive at the next downstream unit 12, the optical signals are at a level which can be received and processed by the unit 12. This process of diverting signals to each unit 12 and amplifying the signals continues at each unit 12. While each unit 12 preferably has an associated amplifier, it should be understood that the amplifiers may not be associated with every unit 12 but should be dispersed throughout the network so as to ensure sufficient signal strength for each unit 12.

The units 12 can provide varying levels of communication functionality. The units 12 may include only a receiver for detecting communications from the other units 12 and may have a transmitter for sending communications to the other units 12. The units 12 may also include additional functionality, such as a display interface. Networks 10 according to the invention may include other numbers of units, may include additional or fewer types of units, and may include only one type of unit. Additional details of the units 12 will become apparent from the description below.

The optical network 10 provides a number of advantages over existing systems that are installed in structures. For one, the units 12 communicate with each other through optical signals. Consequently, the network 10 enjoys immunity from electromagnetic noise whereby electrical systems within the structure 20 do not cause interference with normal operation of any one of the units 12. Furthermore, the optical network 10 includes a single bi-directional bus 14 which can be used to interconnect a large number of units 12 that form part of one or more systems installed within the structure 20. For example, the network 10 can accommodate in the range of 256 units 12 on the single fiber 14. The network 10 therefore presents a viable solution for systems having more than eight to 10 components and, moreover, presents a single solution that can integrate multiple systems. Another advantage of the network 10 is that it greatly simplifies the amount of cabling that needs to be installed within the structure 20. As mentioned above, the network 10 employs a single bi-directional bus 14 with every unit 12 being connected to this one bus 14. This single bi-directional bus 14 greatly simplifies not only the installation of the network 10 into the structure 20 but also the maintenance and repair of the network 10. The network 10 also includes one or more Optical Junction Device (OJD) 17. The

OJDs 17 in effect couple the optical bus 14 to other buses. As shown in Figure 1, the OJDs 17 couple the backbone bus 14 to sub-networks 18, couple sub-networks 18 to sub subnetworks 19, and couple the backbone bus 14 to other networks 22.

In addition to physical connections to external systems or networks such as through the OJDs 17, the network 10 can also be coupled to external systems and networks through wireless interfaces. For instance, as shown in Figure 1, the network 10 may include a wireless input 22 and a wireless output 24. While the wireless input 22 and wireless output 24 have been shown as two separate components, it should be understood that the wireless input 22 and output 24 may be combined into a single unit. Furthermore, the wireless interface provided to the network 10 may include additional wireless inputs and outputs, such as to provide connectivity to different networks.

π. Optical Junction Devices (OJDs)

A schematic diagram of the OJD 17 will now be described in more detail with reference to Figure 2. As shown in Figure 2, optical signals directed into a first port are split and routed out of the other three ports two, three, and four. Similarly, signals that are directed in an opposite direction, such as into port two, are split and routed out of ports three, four, and one. Thus, the OJDs 17 enable the routing of optical signals from one bus that is defined by a path between ports one and two and a second bus defined between ports three and four.

The OJD 17 shown in Figure 2 is suitable for use throughout the network. Thus, the OJD 17 may be used to connect a backbone 14 to a third party network 22 and can be used internally to couple signals off of the backbone 14 onto sub-networks 18. In the example shown in Figure 1, the structure 20 is a three story structure with floors 1, 2, and 3. As shown in the first floor 1 of the structure 20, the OJDs 17 are used to connect a backbone 14 to the third party network 22, to join sub-networks 18 to the backbone, and to join sub-networks 18 to one or more sub sub-networks 19. III. Optical Interface Devices (OIDs)

A component diagram of the OID 16 is shown in Figure 3. It should be understood that the component diagram is one example of how a OID 16 may be fabricated and other methods of fabrication are encompassed by the invention. As shown in this diagram, the OID 16 includes a first coupler 32 that splits light traveling in a first direction A into two components with one being directed to a coupler 33 and another one being directed to a coupler 34. The coupler 34 diverts the optical signals into two components with one component being delivered out of port 3 and the other component out of port 4. The optical signals traveling through coupler 33 are directed out of port 2. Thus, optical signals input into coupler 32 are routed and diverted to each of the ports two, three, and four. Additional description of a suitable OID may be found in U.S. Patent Nos. 5,898,801 and 5,901,260.

The networks according to the invention greatly simplify installation and maintenance of networks within a structure. Whereas conventional networks would deploy multiple sets of wiring throughout the structure, which creates an organizational challenge, the networks according to the invention can use a minimum of one bus for all of the disparate systems within a structure. The networks according to the invention also enable the integration of multiple systems onto the same sub-networks 18 or sub sub-networks 19. Thus, while it is possible, networks according to the invention need not deploy separate sub-networks 18 for each system. This reduction in components translates not only to an improvement in installation and maintenance but also a direct savings in space and cost of operating the structure.

Networks according to the invention provide a number of advantages over existing networks. For example, the interconnection of units to the networks is greatly simplified. Whereas before units were typically hard wired to a bus or to specific hardware interfaces, units can be added to the networks according to the invention at virtually any location along the bus. The units need not be located in close proximity to other units forming a system and also need not be wired to any dedicated interface. Instead, the units can be coupled to the bus at a location determined to be most convenient. The units can also be formed to have common components. Reference is made to co- pending U.S. patent application Serial No. 09/924,651 filed August 8, 2001, entitled "Fiber Optic Communication and Utility Systems and Methods" for additional details on the units. This commonality between units not only reduces manufacturing costs, but also greatly reduces logistics and support costs. As another example, the networks according to the invention enables diagnostic of the systems and networks during operation. Some conventional networks require that the network be shut down to monitor operations and to perform maintenance or repairs. The networks allow for the monitoring of all communications being carried by the bus at any time and at any point along the bus. The networks according to the invention therefore enable non-invasive monitoring, maintenance, and repair.

The networks according to the invention also facilitates integration and cooperation among units and systems. Thus, each unit and each system can supplement and support other units or systems. The networks allow additional functionality to be provided in one system or in one unit at any time and to allow other units and systems to access the new functionality. In addition to relying on functionality provided in other units or systems, the units or systems can serve as a back-up or as additional capacity to the other units and systems. Thus, in the event of a failure or over-load situation, the units and systems can turn to the other units or systems on the bus for support. The flexibility of the bus also enables the networks to dynamically reconfigure themselves to optimize performance, such as based on the design of a structure or operating status of the structure.

The networks are easily upgradeable. Rather than rewiring the network to include an additional element, a new unit can be added to the bus, again at any location along the bus. This type of upgrade is easy in the sense that there is no need to wire to other systems; instead the networks have an easily extendible bus. In addition to hardware upgrades, units can also be upgraded through software. With both hardware and software upgrades, the units can be upgraded to have improved or new functionality.

The foregoing description of the preferred embodiments of the invention has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

CLAIMS What we claim:

1. A network for use in a structure, comprising: a bi-directional optical bus for carrying optical signals, the optical bus being placed within the structure; the bi-directional optical bus permitting optical signals to travel in both directions simultaneously along the optical bus; a plurality of units for performing at least one of transmitting optical signals onto or receiving optical signals from the bi-directional optical bus; a plurality of passive optical couplers with each optical coupler associated with a corresponding unit; the passive optical couplers and the plurality of units being contained within the structure; the optical couplers for: directing optical signals traveling along the bi-directional optical bus in either direction toward the corresponding unit; and directing optical signals from each unit onto the bi-directional optical bus in both directions; an optical amplifier for amplifying the optical signals, the optical amplifier being located within the structure; the optical amplifier for performing amplification of the optical signals traveling in both directions; wherein the passive optical coupler is also for coupling the bi-directional optical bus to a second optical bus associated with a second network.

2. The system as set forth in claim 1, wherein the second network comprises a third party network located outside of the structure.

3. The system as set forth in claim 1, wherein the second network comprises a sub-network located within the structure.

4. The system as set forth in claim 1, wherein the structure comprises a multi- level structure and the system further comprises sub-networks located on each level wherein each sub-network includes a secondary bi-directional optical bus and the passive optical coupler joining the secondary bi-directional optical bus to the bi-directional optical bus.

5. The system as set forth in claim 1, wherein the units comprise processors that form a data system.

6. The system as set forth in claim , wherein the units comprise telephony devices that form part of a telecommunication system.

7. The system as set forth in claim 1 , wherein the bi-directional optical bus comprises a plurality of bi-directional optical buses.