DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

[0068] With the present invention, video signaling processing hardware that is present within the subscriber's premises for tuning video programs can be minimized or reduced without sacrificing a range of services available to a subscriber from a fiber-to-the-home optical network. In other words, the size and complexity of a set-top box can be reduced and in some cases, the set-top box can be eliminated. It is recognized that set-top boxes are frequently needed because most conventional television sets, at the time of this writing, cannot tune digital channels or Internet Protocol (IP) broadcasts.

[0069] Some components of the present invention may be physically located in a subscriber's premises but would have the main purpose of relaying information back to the subscriber optical interface that is physically located external to a subscriber's premises such as a house. In this way, a service provider can update or maintain more complex network equipment that is accessible on the outside of a subscriber's premises such as a single family home or office.

[0070] Exemplary Base Optical Architecture

[0071] Referring now to the drawings, in which like numerals represent like elements throughout the several Figures, aspects of the present invention and the illustrative operating environment will be described.

[0072] FIG. 1 is a functional block diagram illustrating an exemplary optical network architecture 100 according to the present invention. The exemplary optical network architecture 100 comprises a data service hub 110 . Further details of the data service hub 110 will be discussed in detail below with respect to FIG. 3 .

[0073] The data service hub 110 is coupled to a plurality of outdoor laser transceiver nodes 120 . The laser transceiver nodes 120 , in turn, are each coupled to a plurality of optical taps 130 . The optical taps 130 can be coupled to a plurality of subscriber optical interfaces 140 . Coupled to each subscriber optical interface 140 can be a broadcast receiver 117 such as a television (TV) set, a remote control interface 108 , and a remote control 108 . One focus of the present invention is on the hardware and software used to support communications between the subscriber optical interface (SOI) 140 , the remote control interface 108 , and the remote control 103 .

[0074] Between respective components of the exemplary optical network architecture 100 are optical waveguides such as optical waveguides 150 , 160 , 170 , and 180 . The optical waveguides 150 - 180 are illustrated by arrows where the arrowheads of the arrows illustrate exemplary directions of data flow between respective components of the illustrative and exemplary optical network architecture 100 .

[0075] While only an individual laser transceiver node 120 , an individual optical tap 130 , and an individual subscriber optical interface 140 are illustrated in FIG. 1 , as will become apparent from FIG. 2 and its corresponding description, a plurality of laser transceiver nodes 120 , optical taps 130 , and subscriber optical interfaces 140 can be employed without departing from the scope and spirit of the present invention. Typically, in many of the exemplary embodiments of the multiple service provider system of the present invention, several subscriber optical interfaces 140 can be coupled to one or more optical taps 130 .

[0076] The outdoor laser transceiver node 120 can allocate additional or reduced bandwidth based upon the demand of one or more subscribers that use the subscriber optical interfaces 140 . The outdoor laser transceiver node 120 can be designed to withstand outdoor environmental conditions and can be designed to hang on a strand or fit in a pedestal or “hand hole (underground vault).” The outdoor laser transceiver node can operate in a temperature range between minus 40 degrees Celsius to plus 60 degrees Celsius. The laser transceiver node 120 can operate in this temperature range by using passive cooling devices that do not consume power.

[0077] Unlike the conventional routers disposed between the subscriber optical interface 140 and data service hub 110 , the outdoor laser transceiver node 120 does not require active cooling and heating devices that control the temperature surrounding the laser transceiver node 120 . The RF system of the present invention attempts to place more of the decision-making electronics at the data service hub 110 instead of the laser transceiver node 120 . Typically, the decision-making electronics are larger in size and produce more heat than the electronics placed in the laser transceiver node of the present invention. Because the laser transceiver node 120 does not require active temperature controlling devices, the laser transceiver node 120 lends itself to a compact electronic packaging volume that is typically smaller than the environmental enclosures of conventional routers. Further details of the components that make up the laser transceiver node 120 will be discussed in further detail below with respect to FIG. 4 .

[0078] In one exemplary embodiment of the present invention, three trunk optical waveguides 160 , 170 , and 180 (that can comprise optical fibers) can propagate optical signals from the data service hub 110 to the outdoor laser transceiver node 120 . It is noted that the term “optical waveguide” used in the present application can apply to optical fibers, planar light guide circuits, and fiber optic pigtails and other like optical waveguide components that are used to form an optical architecture.

[0079] A first optical waveguide 160 can carry downstream broadcast analog video and control signals. The analog signals can be carried in a traditional cable television format wherein the broadcast signals are modulated onto analog optical carriers with an optical transmitter (not shown in this Figure) in the data service hub 110 . The first optical waveguide 160 can also carry upstream RF signals that are generated by respective video Broadcast receivers 117 .

[0080] A second optical waveguide 170 can carry upstream and downstream targeted services such as data and telephone services to be delivered to or received from one or more subscriber optical interfaces 140 . In addition to carrying subscriber-specific optical signals, the second optical waveguide 170 can also propagate internet protocol broadcast packets, as is understood by those skilled in the art.

[0081] In one exemplary embodiment, a third optical waveguide 180 can transport data signals upstream from the outdoor laser transceiver node 120 to the data service hub 110 . The optical signals propagated along the third optical waveguide 180 can also comprise data and telephone services received from one or more subscribers. Similar to the second optical waveguide 170 , the third optical waveguide 180 can also carry IP broadcast packets, as is understood by those skilled in the art.

[0082] The third or upstream optical waveguide 180 is illustrated with dashed lines to indicate that it is merely an option or part of one exemplary embodiment according to the present invention. In other words, the third optical waveguide 180 can be removed. In another exemplary embodiment, the second optical waveguide 170 propagates optical signals in both the upstream and downstream directions as is illustrated by the double arrows depicting the second optical waveguide 170 .

[0083] In such an exemplary embodiment where the second optical waveguide 170 propagates bidirectional optical signals, only two optical waveguides 160 , 170 would be needed to support the optical signals propagating between the data server's hub 110 in the outdoor laser transceiver node 120 . In another exemplary embodiment (not shown), a single optical waveguide can be the only link between the data service hub 110 and the laser transceiver node 120 . In such a single optical waveguide embodiment, three different wavelengths can be used for the upstream and downstream signals. Alternatively, bi-directional data could be modulated on one wavelength.

[0084] In one exemplary embodiment, the optical tap 130 can comprise an 8-way optical splitter. This means that the optical tap 130 comprising an 8-way optical splitter can divide downstream optical signals eight ways to serve eight different subscriber optical interfaces 140 . In the upstream direction, the optical tap 130 can combine the optical signals received from the eight subscriber optical interfaces 140 .

[0085] In another exemplary embodiment, the optical tap 130 can comprise a 4-way splitter to service four subscriber optical interfaces 140 . Yet in another exemplary embodiment, the optical tap 130 can further comprise a 4-way splitter that is also a pass-through tap meaning that a portion of the optical signal received at the optical tap 130 can be extracted to serve the 4-way splitter contained therein while the remaining optical energy is propagated further downstream to another optical tap or another subscriber optical interface 140 .

[0086] The present invention is not limited to 4-way and 8-way optical splitters. Other optical taps having fewer or more than 4-way or 8-way splits are not beyond the scope of the present invention. The outdoor laser transceiver node 120 , the optical tap 130 , and the optical waveguide disposed between the laser transceiver node and the optical tap 130 can form and can be referred to as a proximate optical network 135 that is close to subscribers.

[0087] Referring now to FIG. 2 , this Figure is a functional block diagram illustrating an exemplary optical network architecture 100 that further includes subscriber groupings 200 that correspond with a respective outdoor laser transceiver node 120 . FIG. 2 illustrates the diversity of the exemplary optical network architecture 100 where a number of optical waveguides 150 coupled between the outdoor laser transceiver node 120 and the optical taps 130 is minimized. FIG. 2 also illustrates the diversity of subscriber groupings 200 that can be achieved with the optical tap 130 .

[0088] Each optical tap 130 can comprise an optical splitter. The optical tap 130 allows multiple subscriber optical interfaces 140 to be coupled to a single optical waveguide 150 that is coupled to the outdoor laser transceiver node 120 . In one exemplary embodiment, six optical fibers 150 are designed to be coupled to the outdoor laser transceiver node 120 . Through the use of the optical taps 130 , sixteen subscribers can be assigned to each of the six optical fibers 150 that are coupled to the outdoor laser transceiver node 120 .

[0089] In another exemplary embodiment, twelve optical fibers 150 can be coupled to the outdoor laser transceiver node 120 while eight subscriber optical interfaces 140 are assigned to each of the twelve optical fibers 150 . Those skilled in the art will appreciate that the number of subscriber optical interfaces 140 assigned to a particular waveguide 150 that is coupled between the outdoor laser transceiver node 120 and a subscriber optical interface 140 (by way of the optical tap 130 ) can be varied or changed without departing from the scope and spirit of the present invention. Further, those skilled in the art recognize that the actual number of subscriber optical interfaces 140 assigned to the particular fiber optic cable is dependent upon the amount of power available on a particular optical fiber 150 .

[0090] As depicted in subscriber grouping 200 , many configurations for supplying communication services to subscribers are possible. For example, while optical tap 130 _A can connect subscriber optical interfaces 140 _A1 through subscriber optical interface 140 _AN to the outdoor laser transmitter node 120 , optical tap 130 _A can also connect other optical taps 130 such as optical tap 130 _AN to the laser transceiver node 120 . The combinations of optical taps 130 with other optical taps 130 in addition to combinations of optical taps 130 with subscriber optical interfaces 140 are limitless. With the optical taps 130 , concentrations of distribution optical waveguides 150 at the laser transceiver node 120 can be reduced. Additionally, the total amount of fiber needed to service a subscriber grouping 200 can also be reduced.

[0091] With the active laser transceiver node 120 of the present invention, the distance between the laser transceiver node 120 and the data service hub 110 can comprise a range between 0 and 80 kilometers. However, the present invention is not limited to this range. Those skilled in the art will appreciate that this range can be expanded by selecting various off-the-shelf components that make up several of the devices of the present system.

[0092] Those skilled in the art will appreciate that other configurations of the optical waveguides disposed between the data service hub 110 and outdoor laser transceiver node 120 are not beyond the scope of the present invention. Because of the bi-directional capability of optical waveguides, variations in the number and directional flow of the optical waveguides disposed between the data service hub 110 and the outdoor laser transceiver node 120 can be made without departing from the scope and spirit of the present invention.

[0093] Referring now to FIG. 3 , this functional block diagram illustrates an exemplary data service hub 110 of the present invention for an individual service provider. If an optical network supports another individual service provider within the data service hub 110 as illustrated in FIG. 3 , then all of the components illustrated in FIG. 3 would be replicated to support the other service provider. That is, each service provider would include its own modulators 310 , 315 , an internet router 340 , a telephone switch 345 , laser transceiver node routing device 355 , and optical transmitters 325 and receivers 370 .

[0094] For data services that will be modulated on a single digital optical carrier by time division multiplexed electrical digital data signals received from different service providers, the service providers can share much of the equipment illustrated in FIG. 3 . That is, equipment between the laser transceiver node routing device 355 and the ports 365 and including the laser transceiver node routing device 355 can have inputs for each service provider (not shown in FIG. 3 ).

[0095] The exemplary data service hub 110 illustrated in FIG. 3 is also designed for a two trunk optical waveguide system. That is, this data service hub 110 of FIG. 3 is designed to send and receive optical signals to and from the outdoor laser transceiver node 120 along the first optical waveguide 160 . With this exemplary embodiment, only the second optical waveguide 170 supports bi-directional data flow. In this way, the third optical waveguide 180 discussed above is not needed.

[0096] The data service hub 110 can comprise one or more modulators 310 , 315 that are designed to support television broadcast services. The one or more modulators 310 , 315 can be analog or digital type modulators. In one exemplary embodiment, there can be at least 78 modulators present in the data service hub 110 . Those skilled in the art will appreciate that the number of modulators 310 , 315 can be varied without departing from the scope and spirit of the present invention.

[0097] The signals from the modulators 310 , 315 are combined in a first combiner 320 . The combined video services controller signals and broadcast video signals are supplied to an optical transmitter 325 where these signals are converted into optical form.

[0098] Those skilled in the art will recognize that a number of variations of this signal flow are possible without departing from the scope and spirit of the present invention. For example, some portion of the video signals may be generated and converted to optical form at a remote first data service hub 110 . At a second data service hub 110 , they may be combined with other signals generated locally.

[0099] The optical transmitter 325 can comprise one of Fabry-Perot (F-P) laser, distributed feedback laser (DFB), or Vertical Cavity Surface Emitting Laser (VCSEL). However, other types of optical transmitters are possible and are not beyond the scope of the present invention. With the aforementioned optical transmitters 325 , the data service hub 110 lends itself to efficient upgrading by using off-the-shelf hardware to generate optical signals.

[0100] The optical signals generated by the optical transmitter 325 are propagated to amplifier 330 such as an Erbium Doped Fiber Amplifier (EDFA) where the optical signals are amplified. The amplified optical signals are then propagated out of the data service hub 110 via a video signal input/output port 335 which is coupled to one or more first optical waveguides 160 .

[0101] The data service hub 110 illustrated in FIG. 3 can further comprise an Internet router 340 . The data service hub 110 can further comprise a telephone switch 345 that supports telephony service to the subscribers of the optical network system 100 . However, other telephony service such as Internet Protocol telephony can be supported by the data service hub 110 . If only Internet Protocol telephony is supported by the data service hub 110 , then it is apparent to those skilled in the art that the telephone switch 345 could be eliminated in favor of lower cost VoIP equipment. For example, in another exemplary embodiment (not shown), the telephone switch 345 could be substituted with other telephone interface devices such as a soft switch and gateway. But if the telephone switch 345 is needed, it may be located remotely from the data service hub 110 and can be coupled through any of several conventional methods of interconnection.

[0102] The data service hub 110 can further comprise a logic interface 350 that is coupled to a laser transceiver node routing device 355 . The logic interface 350 can comprise a Voice over Internet Protocol (VOIP) gateway when required to support such a service. The laser transceiver node routing device 355 can comprise a conventional router that supports an interface protocol for communicating with one or more laser transceiver nodes 120 . This interface protocol can comprise one of gigabit or faster Ethernet, Internet Protocol (IP) or SONET protocols. However, the present invention is not limited to these protocols. Other protocols can be used without departing from the scope and spirit of the present invention.

[0103] The logic interface 350 and laser transceiver node routing device 355 can read packet headers originating from the laser transceiver nodes 120 and the internet router 340 . The logic interface 350 can also translate interfaces with the telephone switch 345 . After reading the packet headers, the logic interface 350 and laser transceiver node routing device 355 can determine where to send the packets of information.

[0104] The laser transceiver node routing device 355 can also supply downstream data signals to respective optical transmitters 325 . The data signals converted by the optical transmitters 325 can then be propagated to a bi-directional splitter 360 . The optical signals sent from the optical transmitter 325 into the bi-directional splitter 360 can then be propagated towards a bi-directional data input/output port 365 that is coupled to a second optical waveguide 170 that supports bi-directional optical data signals between the data service hub 110 and a respective laser transceiver node 120 .

[0105] Upstream optical signals received from a respective laser transceiver node 120 can be fed into the bi-directional data input/output port 365 where the optical signals are then forwarded to the bi-directional splitter 360 . From the bi-directional splitter 360 , respective optical receivers 370 can convert the upstream optical signals into the electrical domain. The upstream electrical signals generated by respective optical receivers 370 are then fed into the laser transceiver node routing device 355 . As noted above, each optical receiver 370 can comprise one or more photoreceptors or photodiodes that convert optical signals into electrical signals.

[0106] When distances between the data service hub 110 and respective laser transceiver nodes 120 are modest, the optical transmitters 325 can propagate optical signals at 1310 nm. But where distances between the data service hub 110 and the laser transceiver node are more extreme, the optical transmitters 325 can propagate the optical signals at wavelengths of 1550 nm with or without appropriate amplification devices.

[0107] According to one exemplary embodiment, most of the data services are transported by a digital optical carrier having a wavelength of 1310 nm. Meanwhile, the broadcast services are transported by analog optical carriers in the 1550 nm wavelength region. An optical diplexer 515 (discussed below and illustrated in FIG. 5 ) will separate the digital optical carrier from the one or more analog optical carriers according to the carriers respective wavelength.

[0108] Those skilled in the art will appreciate that the selection of optical transmitters 325 for each circuit may be optimized for the optical path lengths needed between the data service hub 110 and the outdoor laser transceiver node 120 . Further, those skilled in the art will appreciate that the wavelengths discussed are practical but are only illustrative in nature. In some scenarios, it may be possible to use communication windows at 1310 and 1550 nm in different ways without departing from the scope and spirit of the present invention. Further, the present invention is not limited to a 1310 and 1550 nm wavelength regions. Those skilled in the art will appreciate that smaller or larger wavelengths for the optical signals are not beyond the scope and spirit of the present invention.

[0109] Referring now to FIG. 4 , this Figure illustrates a functional block diagram of an exemplary outdoor laser transceiver node 120 of the present invention. In this exemplary embodiment, the laser transceiver node 120 can comprise an optical signal input port 405 that can receive optical signals propagated from the data service hub 110 that are propagated along a first optical waveguide 160 . The optical signals received at the optical signal input port 405 can comprise downstream broadcast video data.

[0110] The downstream broadcast video data can also comprise downstream video service control signals. The downstream broadcast video data is typically modulated on an analog optical carrier.

[0111] The downstream optical signals received at the input port 405 are propagated through an amplifier 410 such as an Erbium Doped Fiber Amplifier (EDFA) in which the optical signals are amplified. The amplified optical signals are then propagated to an optical splitter 415 that divides the downstream broadcast video optical signals (that may also include video service control signals if sent on modulated carriers) among diplexers 420 that are designed to forward optical signals to predetermined subscriber groups 200 .

[0112] The laser transceiver node 120 can further comprise a bi-directional optical signal input/output port 425 that connects the laser transceiver node 120 to a second optical waveguide 170 that supports bi-directional data flow between the data service hub 110 and laser transceiver node 120 . Downstream optical signals flow through the bi-directional optical signal input/output port 425 to an optical waveguide transceiver 430 that converts downstream optical signals into the electrical domain.

[0113] The optical waveguide transceiver 430 further converts upstream electrical signals into the optical domain. The optical waveguide transceiver 430 can comprise an optical/electrical converter and an electrical/optical converter. Downstream and upstream electrical signals are communicated between the optical waveguide transceiver 430 and an optical tap routing device 435 .

[0114] The optical tap routing device 435 can manage the interface with the data service hub optical signals and can route or divide or apportion the data service hub signals according to individual tap multiplexers 440 that communicate optical signals with one or more optical taps 130 and ultimately one or more subscriber optical interfaces 140 . It is noted that tap multiplexers 440 operate in the electrical domain to modulate laser transmitters in order to generate optical signals that are assigned to groups of subscribers coupled to one or more optical taps.

[0115] Optical tap routing device 435 is notified of available upstream data packets and upstream RF packets as they arrive, by each tap multiplexer 440 . The optical tap routing device is coupled to each tap multiplexer 440 to receive these upstream data and RF packets. The optical tap routing device 435 can relay upstream video control return packets and information packets that can comprise data and/or telephony packets to the data service hub 110 via the optical waveguide transceiver 430 and bidirectional optical signal input/output 425 . The optical tap routing device 435 can build a lookup table from these upstream data packets coming to it from all tap multiplexers 440 (or ports), by reading the source IP address of each packet, and associating it with the tap multiplexer 440 through which it came.

[0116] The aforementioned lookup table can be used to route packets in the downstream path. As each downstream data packet comes in from the optical waveguide transceiver 430 , the optical tap routing device looks at the destination IP address (which is the same as the source IP address for the upstream packets). From the lookup table the optical tap routing device 435 can determine which port (or, tap multiplexer 440 ) is coupled to that IP address, so it sends the packet to that port. This can be described as a normal layer 3 router function as is understood by those skilled in the art.

[0117] The optical tap routing device 435 can assign multiple subscribers to a single port. More specifically, the optical tap routing device 435 can service groups of subscribers with corresponding respective, single ports. The optical taps 130 coupled to respective tap multiplexers 440 can supply downstream optical signals to pre-assigned groups of subscribers who receive the downstream optical signals with the subscriber optical interfaces 140 .

[0118] In other words, the optical tap routing device 435 can determine which tap multiplexers 440 is to receive a downstream electrical signal, or identify which tap multiplexer 440 propagated an upstream optical signal (that is received as an electrical signal). The optical tap routing device 435 can format data and implement the protocol required to send and receive data from each individual subscriber coupled to a respective optical tap 130 . The optical tap routing device 435 can comprise a computer or a hardwired apparatus that executes a program defining a protocol for communications with groups of subscribers assigned to individual ports. Exemplary embodiments of programs defining the protocol is discussed in the following copending and commonly assigned non-provisional patent applications, the entire contents of which are hereby incorporated by reference: “Method and System for Processing Downstream Packets of an Optical Network,” filed on Oct. 26, 2001 in the name of Stephen A. Thomas et al. and assigned U.S. Ser. No. 10/045,652; and “Method and System for Processing Upstream Packets of an Optical Network,” filed on Oct. 26, 2001 in the name of Stephen A. Thomas et al. and assigned U.S. Ser. No. 10/045,584.

[0119] The single ports of the optical tap routing device 435 are coupled to respective tap multiplexers 440 . With the optical tap routing device 435 , the laser transceiver node 120 can adjust a subscriber's bandwidth on a subscription basis or on an as-needed or demand basis. The laser transceiver node 120 via the optical tap routing device 435 can offer data bandwidth to subscribers in pre-assigned increments. For example, the laser transceiver node 120 via the optical tap routing device 435 can offer a particular subscriber or groups of subscribers bandwidth in units of 1, 2, 5, 10, 20, 50, 100, 200, and 450 Megabits per second (Mb/s). Those skilled in the art will appreciate that other subscriber bandwidth units are not beyond the scope of the present invention.

[0120] Electrical signals are communicated between the optical tap routing device 435 and respective tap multiplexers 440 . The tap multiplexers 440 propagate optical signals to and from various groupings of subscribers by way of laser optical transmitter 525 and laser optical receiver 370 . Each tap multiplexer 440 is coupled to a respective optical transmitter 325 . As noted above, each optical transmitter 325 can comprise one of a Fabry-Perot (F-P) laser, a distributed feedback laser (DFB), or a Vertical Cavity Surface Emitting Laser (VCSEL). The optical transmitters produce the downstream optical signals that are propagated towards the subscriber optical interfaces 140 . Each tap multiplexer 440 is also coupled to an optical receiver 370 . Each optical receiver 370 , as noted above, can comprise photoreceptors or photodiodes. Since the optical transmitters 325 and optical receivers 370 can comprise off-the-shelf hardware to generate and receive respective optical signals, the laser transceiver node 120 lends itself to efficient upgrading and maintenance to provide significantly increased data rates.

[0121] Each optical transmitter 325 and each optical receiver 370 are coupled to a respective bi-directional splitter 360 . Each bi-directional splitter 360 in turn is coupled to a diplexer 420 which combines the optical signals received from the splitter 415 with the downstream optical signals received from respective optical receivers 370 . In this way, broadcast video services as well as data services can be supplied with a single optical waveguide such as a distribution optical waveguide 150 as illustrated in FIG. 2 . In other words, optical signals can be coupled from each respective diplexer 420 to a combined signal input/output port 445 that is coupled to a respective distribution optical waveguide 150 .

[0122] Unlike the conventional art, the laser transceiver node 120 does not employ a conventional router. The components of the laser transceiver node 120 can be disposed within a compact electronic packaging volume. For example, the laser transceiver node 120 can be designed to hang on a strand or fit in a pedestal similar to conventional cable TV equipment that is placed within the “last,” mile or subscriber proximate portions of a network. It is noted that the term, “last mile,” is a generic term often used to describe the last portion of an optical network that connects to subscribers.

[0123] Also because the optical tap routing device 435 is not a conventional router, it does not require active temperature controlling devices to maintain the operating environment at a specific temperature. Optical tap routing device 435 does not need active temperature controlling devices because it can be designed with all temperature-rated components. In other words, the laser transceiver node 120 can operate in a temperature range between minus 40 degrees Celsius to 60 degrees Celsius in one exemplary embodiment.

[0124] While the laser transceiver node 120 does not comprise active temperature controlling devices that consume power to maintain temperature of the laser transceiver node 120 at a single temperature, the laser transceiver node 120 can comprise one or more passive temperature controlling devices 450 that do not consume power. The passive temperature controlling devices 450 can comprise one or more heat sinks or heat pipes that remove heat from the laser transceiver node 120 . Those skilled in the art will appreciate that the present invention is not limited to these exemplary passive temperature controlling devices. Further, those skilled in the art will also appreciate the present invention is not limited to the exemplary operating temperature range disclosed. With appropriate passive temperature controlling devices 450 , the operating temperature range of the laser transceiver node 120 can be reduced or expanded.

[0125] In addition to the laser transceiver node's 120 ability to withstand harsh outdoor environmental conditions, the laser transceiver node 120 can also provide high speed symmetrical data transmissions. In other words, the laser transceiver node 120 can propagate the same bit rates downstream and upstream to and from a network subscriber. This is yet another advantage over conventional networks, which typically cannot support symmetrical data transmissions as discussed in the background section above. Further, the laser transceiver node 120 can also serve a large number of subscribers while reducing the number of connections at both the data service hub 110 and the laser transceiver node 120 itself.

[0126] The laser transceiver node 120 also lends itself to efficient upgrading that can be performed entirely on the network side or data service hub 110 side. That is, upgrades to the hardware forming the laser transceiver node 120 can take place in locations between and within the data service hub 110 and the laser transceiver node 120 . This means that the subscriber side of the network (from distribution optical waveguides 150 to the subscriber optical interfaces 140 ) can be left entirely intact during an upgrade to the laser transceiver node 120 or data service hub 110 or both.

[0127] The following is provided as an example of an upgrade that can be employed utilizing the principles of the present invention. In one exemplary embodiment of the invention, the subscriber side of the laser transceiver node 120 can service six groups of 16 subscribers each for a total of up to 96 subscribers. Each group of 16 subscribers can share a data path of about 450 Mb/s speed. Six of these paths represents a total speed of 6×450=2.7 Gb/s. In the most basic form, the data communications path between the laser transceiver node 120 and the data service hub 110 can operate at 1 Gb/s. Thus, while the data path to subscribers can support up to 2.7 Gb/s, the data path to the network can only support 1 Gb/s. This means that not all of the subscriber bandwidth is useable. This is not normally a problem due to the statistical nature of bandwidth usage.

[0128] An upgrade could be to increase the 1 Gb/s data path speed between the laser transceiver node 120 and the data service hub 110 . This may be done by adding more 1 Gb/s data paths. Adding one more path would increase the data rate to 2 Gb/s, approaching the total subscriber-side data rate. A third data path would allow the network-side data rate to exceed the subscriber-side data rate. In other exemplary embodiments, the data rate on one link could rise from 1 Gb/s to 2 Gb/s then to 10 Gb/s, so when this happens, a link can be upgraded without adding more optical links.

[0129] The additional data paths (bandwidth) may be achieved by any of the methods known to those skilled in the art. It may be accomplished by using a plurality of optical waveguide transceivers 430 operating over a plurality of optical waveguides, or they can operate over one optical waveguide at a plurality of wavelengths, or it may be that higher speed optical waveguide transceivers 430 could be used as shown above. Thus, by upgrading the laser transceiver node 120 and the data service hub 110 to operate with more than a single 1 Gb/s link, a system upgrade is effected without having to make changes at the subscribers' premises.

[0130] Referring now to FIG. 5 , this Figure is a functional block diagram illustrating an optical tap 130 coupled to a subscriber optical interface 140 by a single optical waveguide 150 according to one exemplary embodiment of the present invention. The optical tap 130 can comprise a combined signal input/output port 505 that is coupled to another distribution optical waveguide that is coupled to a laser transceiver node 120 . As noted above, the optical tap 130 can comprise an optical splitter 510 that can be a 4-way or 8-way optical splitter. Other optical taps having fewer or more than 4-way or 8-way splits are not beyond the scope of the present invention.

[0131] The optical tap can divide downstream optical signals to serve respective subscriber optical interfaces 140 . In the exemplary embodiment in which the optical tap 130 comprises a 4-way optical tap, such an optical tap can be of the pass-through type, meaning that a portion of the downstream optical signals is extracted or divided to serve a 4-way splitter contained therein, while the rest of the optical energy is passed further downstream to other distribution optical waveguides 150 .

[0132] The optical tap 130 is an efficient coupler that can communicate optical signals between the laser transceiver node 120 and a respective subscriber optical interface 140 . Optical taps 130 can be cascaded, or they can be coupled in a star architecture from the laser transceiver node 120 . As discussed above, the optical tap 130 can also route signals to other optical taps that are downstream relative to a respective optical tap 130 .

[0133] The optical tap 130 can also connect to a limited or small number of optical waveguides so that high concentrations of optical waveguides are not present at any particular laser transceiver node 120 . In other words, in one exemplary embodiment, the optical tap can connect to a limited number of optical waveguides 150 at a point remote from the laser transceiver node 120 so that high concentrations of optical waveguides 150 at a laser transceiver node can be avoided. However, those skilled in the art will appreciate that the optical tap 130 can be incorporated within the laser transceiver node 120 .

[0134] The subscriber optical interface 140 functions to convert downstream optical signals received from the optical tap 130 into the electrical domain that can be processed with appropriate communication devices. The subscriber optical interface illustrated in FIG. 5 is a basic unit. Further details of a preferred unit will be described below with respect to FIG. 7 . The subscriber optical interface 140 functions to convert upstream electrical signals into upstream optical signals that can be propagated along a distribution optical waveguide 150 to the optical tap 130 . The subscriber optical interface 140 can comprise an optical diplexer 515 that divides the downstream optical signals received from the distribution optical waveguide 150 between a bi-directional optical signal splitter 520 and an analog optical receiver 525 .

[0135] The optical diplexer 515 can separate or divide downstream optical signals based on wavelength. Typically, digital optical carriers will be propagated at a first wavelength while analog optical carriers will be propagated at second and third wavelengths different from the first wavelength.

[0136] The optical diplexer 515 can receive upstream optical signals generated by a digital optical transmitter 530 . The digital optical transmitter 530 converts electrical binary/digital signals to optical form so that the optical signals can be transmitted back to the data service hub 110 . Conversely, the digital optical receiver 540 converts optical signals into electrical binary/digital signals so that the electrical signals can be handled by processor 550 .

[0137] The analog optical receiver 525 can convert the downstream, analog broadcast optical video signals into modulated RF television signals that are propagated out of the modulated RF signal output 535 . The modulated RF signal output 535 can feed Broadcast receivers 117 such as video service terminals like television sets and radios. The analog optical receiver 525 could process analog modulated RF transmission as well as digitally modulated RF transmissions for digital TV applications.

[0138] The bi-directional optical signal splitter 520 can propagate combined optical signals in their respective directions. That is, downstream optical signals entering the bi-directional optical splitter 520 from the optical diplexer 515 , are propagated to the digital optical receiver 540 . Upstream optical signals entering the splitter 520 from the digital optical transmitter 530 are sent to optical diplexer 515 and then to optical tap 130 . The bi-directional optical signal splitter 520 is coupled to a digital optical receiver 540 that converts downstream data optical signals into the electrical domain. Meanwhile the bi-directional optical signal splitter 520 is also coupled to a digital optical transmitter 530 that converts upstream electrical signals into the optical domain.

[0139] The digital optical receiver 540 can comprise one or more photoreceptors or photodiodes that convert optical signals into the electrical domain. The digital optical transmitter can comprise one or more lasers such as the Fabry-Perot (F-P) Lasers, distributed feedback lasers, and Vertical Cavity Surface Emitting Lasers (VCSELs).

[0140] The digital optical receiver 540 and digital optical transmitter 530 are coupled to a processor 550 that selects data intended for the instant subscriber optical interface 140 based upon an embedded address. The data handled by the processor 550 can comprise one or more of telephony and data services such as an Internet service. The processor 550 is coupled to a telephone input/output 555 that can comprise an analog interface.

[0141] The processor 550 is also coupled to a data interface 560 that can provide a link to computer devices, set top boxes, ISDN phones, and other like devices. Alternatively, the data interface 560 can comprise an interface to a Voice over Internet Protocol (VoIP) telephone or Ethernet telephone. The data interface 560 can comprise one of Ethernet's (10BaseT, 100BaseT, Gigabit) interface, HPNA interface, a universal serial bus (USB) an IEEE1394 interface, an ADSL interface, and other like interfaces.

[0142] Exemplary Equipment Supported by SOI

[0143] Referring now to FIG. 6 , this Figure is a functional block diagram illustrating exemplary subscriber equipment that can be serviced by the subscriber optical interface 140 according to an exemplary embodiment of the present invention. The subscriber optical interface 140 may service data equipment such as computers 562 and telephones 564 . For video equipment, the subscriber optical interface 104 can support digital video interfaces 619 that relay signals between the SOI 140 and a TV. For other video equipment, the output from the modulated RF signal output 535 may be split among a plurality of TV sets 117 and other devices such as recorders 119 that can include personal video recorders or video cassette recorders and other like equipment. An electrical splitter 605 can be used to split or divide the RF signals, and to combine return control signals as described below.

[0144] The signals propagating along the electrical waveguide may comprise analog-modulated RF carriers that may be tuned directly by a TV 117 . In certain cases, control interfaces 108 between the Subscriber Optical Interface 140 and the TV may be used. Their operation will be described in greater detail below.

[0145] In order to effect control of a TV 117 and the decoding and tuning devices in the Subscriber Optical Interface 140 , a remote control handheld unit 103 can be used. The remote control 103 may communicate with the TV 117 using the TV's remote control receiver (usually but not necessarily, the remote control operates using infrared—IR—signals. Other signaling, such as RF or ultrasonic, may be used and is not beyond the scope and spirit of the present invention).

[0146] The remote control handheld unit 103 is designed to communicate with the Subscriber Optical Interface 140 , and may do so via a control interface 108 connected to the RF cable 610 from the Subscriber Optical Interface 140 to the TV 117 . A number of variations on the construction and operation of the remote control handheld unit 103 and the control interface 108 will be described in greater detail below. According to one preferred and exemplary embodiment, a control interface 108 is not used.

[0147] Those skilled in the art will appreciate that the same remote control hand-held unit 103 that controls the TV 117 can control the recorder 119 and other consumer electronics devices. This detailed description will primarily discuss controlling the TV, but it is understood that other devices may also be controlled by the same remote control hand-held unit 103 .

[0148] Exemplary Hardware of the Subscriber Optical Interface 140

[0149] Referring now to FIG. 7 , this Figure is a functional block diagram illustrating a several additional exemplary components that may be contained in the subscriber optical interface 140 according to one preferred and exemplary embodiment of the present invention. From analog optical receiver 525 , the modulated RF signals may be split along several paths of which three are shown by way of example but not limitation. The splitting is performed in an electrical RF splitter 605 that can split or divide the RF signals. The top direct path 702 is for signals that are to be tuned directly by the TV set 117 . As of this writing, these signals are standard analog-modulated TV signals according to the NTSC standard in North America, and according to either the PAL or SECAM standards in other countries. These standards are well known to those skilled in the art.

[0150] These signals are supplied directly to the TV set(s) 117 by way of diplexers 720 A and 720 B. The functionality of these two diplexers 720 A, 720 B will be described below, where a plurality of embodiments will be shown. The signals are output to the TV set(s) 117 through the Modulated Signal Output 535 . (In rare cases a set top terminal, STT, may be used at the TV 117 , but in general, this invention removes the need for a conventional STT.)

[0151] The second signal path is supplied to an RF tuner 704 A, which converts the modulated RF signal to baseband for further processing. The tuner 704 A may be used for either analog-modulated or digital-modulated RF signals as is understood by those skilled in the art. Analog-modulated signals are demodulated in analog demodulator 310 A. The main reason why an analog signal may be modulated at this point is if it is to be displayed on a TV 117 that is not capable of tuning the channel in question. Another reason would be if it is desired to display the channel on a display, such as a home theater, that is connected via a digital interface and does not have an RF tuner associated with it.

[0152] The demodulated analog signal from analog demodulator 310 A is supplied to a VBI decoder 710 , which is used to recover VBI data such as closed captioning information, well known to those skilled in the art. This data is used primarily to add captioning for hearing impaired viewers. The VBI decoder 710 recovers the VBI data and supplies it to a multimedia processor 714 A that can add the closed captioning information to the programming signal. The multimedia processor 714 A is also capable of adding text and graphics to the video signal, among other tasks. It is also connected to processor 550 , and can be used to supply messages to viewers in the form of on-screen text and graphics as will be described below.

[0153] From the multimedia processor 714 A, the signal is supplied to an agile RF modulator 718 A, another component well known to those skilled in the art. It modulates the video and audio signals onto an RF carrier for transmission to the TV set 117 .

[0154] The signal from RF tuner 704 A may also go to digital demodulator 706 A, which is used in place of analog demodulator 310 A if the tuned signal is digitally modulated. From the digital demodulator 706 A, the signal may be supplied to a POD 708 A, or Point of Deployment module 708 A. This module 708 A can descramble a signal if it is transmitted scrambled over the fiber optic plant. The inner functionality of the POD module 708 A is shown for POD module 708 B, and will be explained below. A POD module is also known commercially as a CableCard.

[0155] The descrambled digital signal from POD module 708 A can be passed to an MPEG decoder 712 A that can recover an analog picture from the digital signal. Alternatively, it can output an MPEG-decoded digital signal ready to have any overlay information added in the multimedia processor 714 A and passed through to a digital display output such as the DVI interface (HDCP) 740 . As another option, the video signal can be outputted to an S-video interface 738 . Further details of the S-Video interface will be described below with respect to FIG. 19 . Finally, the MPEG decoder 712 A may do nothing except to pass through the MPEG encoded signal, if that signal is to be delivered on an interface designed to accommodate MPEG signals to the display device. Such an output is the DTCP 742 and 1394 interface. These output types are understood by those skilled in the art, and will be explained more fully below.

[0156] To explain in more detail, Cable Television Laboratories (CableLabs), has specified standard interfaces between a host device, which the Subscriber Optical Interface 140 is acting as in this case, and a display device such as a TV. The OpenCable™ Host Device core Functional Requirements document, OC-SP-HOSTCFR-I11-021126, calls for analog and two (including HDTV) types of digital video connections. The first digital interface is the DVI interface 740 , specified as applying only for a high definition display.

[0157] The high definition display requires the compressed MPEG signal to be decompressed and converted to video components by the host device, in this case, the Subscriber Optical Interface 140 . This requirement includes the requirement to verify the display device to show that it is permitted to display the output, and then to encrypt the display data so that it cannot be supplied to any other devices. This specification requires that the multimedia processor 714 to add any graphic elements to the video. The interface is called the DVI interface, and the verification and encryption is called HDCP.

[0158] The other digital video interface is called 1394, after the IEEE specification used for communications. The corresponding verification and encryption system is known as DTCP 742. This interface 1394 is transmitted in MPEG compressed format, relying on the using device, such as a TV or VCR, to decompress the video. This specification also allows for transmission of a separate graphic to overlay the video, relying on the TV to merge the overlay with the picture.

[0159] Thus, MPEG decoder 712 A and multimedia processor 714 A are not needed for output material intended for output on the 1394/DTCP output 742 , but they are required for material intended for output on the DVI/HDCP output 740 . They also would be required for output on any analog outputs, such as that going to an agile RF modulator 718 A. (Other analog outputs such as composite and YPrPb are not shown, but are within the scope of the invention. They are well known to those skilled in the art.) The output going to the multiplexing and format conditioning 746 is video and audio display data that is to be delivered over a data path, such as data interface 560 . This is possible and is within the scope of the instant invention, but as of this writing, there are no industry standards for doing so.

[0160] A second RF tuner 704 B is illustrated and is intended to allow the Subscriber Optical Interface 140 to serve two or more TVs simultaneously, one being served via tuner 704 A and one being served by tuner 704 B. Yet another one or more TVs can be served directly via the direct path 702 . Furthermore, more than two RF tuners 704 may be used. It is possible to provide some tuners 704 built into the Subscriber Optical Interface 140 , and to provide provisions for additional tuners 704 and associated components to be plugged in for those subscribers demanding more service.

[0161] The second tuner 704 B is connected to a second digital demodulator 706 B. It could also be connected to another analog demodulator 310 A. However, in most instances, few analog signals would be handled on other than the direct path 702 , so it is generally not necessary to provide for a lot of analog demodulators 310 A. The output of digital demodulator 706 B is supplied to a second POD module 708 B.

[0162] This second module 708 B is identical to POD module 708 A described above. The POD module 708 B is defined in the specifications OpenCable™ POD Copy Protection System, OC-SP-PODCP-IF-108-021126 and OpenCable™ Host-POD Interface Specification, OC-SP-HOSTPOD-IF-I11-021126, well known to those skilled in the art. The purpose of the POD modules 708 is to provide for communications between the Subscriber Optical Interface 140 and control systems located at the data service hub 110 . It also provides descrambling of the incoming digital modulated signal when it is scrambled, and handles copy protection for the descrambled MPEG signal it passes to the remainder of the Subscriber Optical Interface 140 .

[0163] The POD module 708 B comprises an out-of-band (OOB) processing submodule 728 that handles communications between the data service hub 110 and the Subscriber Optical Interface 140 . This is done via the OOB channel 730 . The OOB channel 730 comprises QPSK tuner 732 and QPSK demodulator 734 . These components recover downstream control information transmitted according to one of two SCTE specifications, SCTE-167 or SCTE 178. These specifications are well known to those skilled in the art, and prescribe ways to transmit control data to set top terminals, STTs. The same control channel can transmit control data to the Subscriber Optical Interface 140 in the instant invention.

[0164] The two SCTE specifications also prescribe upstream communications paths that are not practical in FTTH systems such as the instant system. Rather, upstream communications may be effected or achieved by putting the upstream data in packets and sending them back to the data service hub 110 on the normal data path. At the data service hub 110 the data packets are converted to RF signals for delivery to the control system. A similar technology is taught in the commonly-owned application, entitled, “Method and System for Providing a Return Path for Signals Generated by Legacy Terminals in an Optical Network,” Non-provisional patent application No. 10/041,299. For these communications to take place, the return data path 752 from the OOB processing module 728 to processor 550 is utilized. There is no need in the instant invention to actually generate the RF signal at the Subscriber Optical Interface 140 .

[0165] Besides the OOB processing submodule 728 , the POD module comprises a conditional access module 726 , which handles authorization of reception of individual channels and programs, including descrambling the signal transmitted over the fiber. Finally, the second POD module 708 B also comprises copy protection module 724 A, which verifies that the POD module 708 B is plugged into an acceptable host (in this case the Subscriber Optical Interface 140 ), and which encrypts the video at its output to prevent unauthorized detection of the output. All of this is described in the document, OpenCable™ HOST-POD Interface Specification, cited above.

[0166] Operation of the signal flow from second POD module 708 B is identical to that described above for the first POD module 708 A. Additional signal chains may be added as desired.

[0167] In addition to the delivery of broadcast material over RF carriers as described above, it is p