Abstract:
An optical transceiver device having multiple communication related functions is integrated into a single module, as well as capabilities for integrating a DSP and optical side send/receive processing. The optical transceiver device provides client-access and line-access operations on the optical layers for traffic control and security, and enables parallel implementation.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to methods and systems for providing optical communications. In particular, the present invention relates to a multiport optical transceiver having multiple communication related functions, as well as functionalities for interfacing a DSP and optical side send/receive processing into a single multi-interface module.  
       BACKGROUND OF THE INVENTION  
       [0002]     Optical communication networks facilitate the transmission of digital data using optical signals which are formatted to conform to several different synchronous and asynchronous communication standards. A very well known synchronous optical communications standard is Synchronous Optical Network (SONET). SONET systems require a synchronous transport signal which has associated with it section overhead (SOHO) bytes, frames, transport overhead and payload/data bytes.  
         [0003]     SONET systems also allow branching of various DS-1 (i.e., T1 data streams) of 1.54 Mb/s lines, Digital Multiplex Hierarchy (DMH), add/drop multiplexers (ADMs), etc. into the system to interface the transport layer. ADMs may have cross-connect matrices (i.e., switch fabrics) for directing synchronous transferred signals from one interface to another interface within the system or to other systems in the network.  
         [0004]     A very common asynchronous protocol, called Asynchronous Transfer Mode (ATM), provides a cell-based transport and switching technology for high-capacity transmission of voice, data and video, in 53-byte cells. By using ADMs with appropriately formatted DS-1 channels, it is well known that ATM cells may be transmitted over SONET. The plethora of details regarding these standards and other communication standards and features are well known in the art and, therefore, are not discussed herein.  
         [0005]     Optical communication networks are also understood to require an assortment of dedicated equipment such as optical transceivers, data processors, routers, switches, multiplexers, traffic management servers, control units, network interfaces, etc., all of which in one form or another support a designated communication standard(s) for maintaining communication fidelity and client services.  
         [0006]     One critical hardware component for an optical communication system is the optical transceiver. It is well known that the primary function of conventional optical transceivers is to convert optical signals into electrical signals and convert electrical signals into optical signals. The converted signals, if optical, are usually transmitted over the optical network. If electrical, the converted signals are usually digitally processed by a processor or conveyed to other devices, for example, a signal conditioning system or switch. Accordingly, optical transceivers are usually provided with adjunct capabilities, such as, for example, digital signal processing (DSP) or switch fabric interfaces to adapt data received from the optical network for signal conditioning or routing on the client side.  
         [0007]     DSPs are typically integrated into optical transceivers to pre or post-condition the signals to adjust the received or transmitted signals to account for propagation distortion, pre-emphasis, chromatic distortion, error correction, birefringent effects, connection or traffic related interferences, etc. DSPs also permit monitoring and control of connection issues or traffic issues for more fault resistant network management.  
         [0008]     Concomitant with optical systems utilizing a time-division multiplexing (TDM) paradigm is the implementation of modified optical transceivers to synchronize optical signals of different input data streams with a common clock. In this regard, it is well known that systems are capable of synchronizing the clocks of different input streams with a common clock or with one of the clocks recovered from the input streams.  
         [0009]     On the line side of conventional optical transceivers is usually implemented conventional Serdes-Framer Interfaces (SFI4) which electrically restore the signals. However, these and conventional signal conditioning capabilities in optical transceivers tend to operate on the aggregate send or aggregate receive signal rather than on individual optical side access send or receive signals. Moreover, conventional optical transceivers are not provided with interfaces for processors which would render them more intelligent and more independent.  
         [0010]     As a result, all of the above paradigms for optical communication systems are, in one form or another, accomplished by connecting physically separate systems or subassemblies into a turnkey or hybridized optical transceiver system. Due to the independent operations of these adjunct systems or subassemblies within the optical transceiver, there is the requirement that these adjunct systems or subassemblies must have compatible interfaces designed for the particular optical transceiver being modified. Further, this adjunct systems or subassemblies must be staged with control/operation priorities to perform proper sequencing of the respective operations within the transceiver system. This process of developing such a hybridized optical transceiver system has imposed an increased cost for optical communication providers when upgrading transceiver systems and designing transceiver system configurations for desired operational functionalities.  
         [0011]     Therefore, there has been a longstanding need in the optical transceiver community for a single module, transceiver system with easily interfacable, DSP processing capabilities adaptable to an optical line layer, and client-side optical input/output signal manipulation capabilities.  
       SUMMARY OF THE INVENTION  
       [0012]     According to a first aspect, the invention relates to a multi-port transceiver system interfacable with an optical transceiver, comprising a signal processor coupled to an optical transceiver, a processor interface coupled to the signal processor, an external interface coupled to the signal processor interface, and a client-side optical transceiver coupled to the signal processor, wherein the processor interface enables communication between the signal processor and an external device coupled to the external interface, and the client-side optical transceiver interface enables transceiving of signals between the signal processor and a client-side optical transceiver coupled to the client-side optical transceiver interface.  
         [0013]     According to another aspect, the invention relates to a multi-port transceiver system interfacable with optical transceivers, comprising signal processing means for processing optical transceiving signals, processor interfacing means for interfacing with the signal processing means, external interfacing means for interfacing the processor interfacing means with an external device, and client-side optical transceiver for interfacing the signal processing means with a client-side optical transceiver.  
         [0014]     According to another aspect, the invention relates to a method of transceiving optical signals in a multi-port transceiver system having an internal processor and an internal processor interface coupled to an external interface, the method comprising the steps of processing by the internal signal processor, signal received by or for transmission by optical transceivers, providing additional processing to the internal signal processor by coupling an external processor to the external interface and processing by the internal signal processor, a signal communicated by a client-side optical transceiver interface. 
     
    
       [0015]     Other features and advantages of the invention are described below and are apparent from the accompanying drawings and from the following detailed description.  
         [0016]      FIG. 1  is a block diagram of an exemplary multiport optical transceiver system according to this invention.  
         [0017]      FIG. 2  is a block diagram of the exemplary multiport optical transceiver system of  FIG. 1  in multi-gigabit configuration. 
     
    
     DETAILED DESCRIPTION  
       [0018]     Typical optical transceiver systems utilizing SONET, SDH, ATM, etc. networks are developed as turnkey systems wherein most or all of the desired functionalities are provided by connecting separate independent systems to form the desired optical transceiver system. Therefore, conventional optical transceiver systems do not provide a single module capable of performing the desired functionalities, having client side optical inputs/outputs, an optional integrated DSP, or interfacing/deinterfacing capabilities, etc. Accordingly, this invention provides methods and systems for addressing these and other shortcomings in the prior art.  
         [0019]      FIG. 1  is a block diagram of an exemplary optical transceiver system  200  according to an embodiment of this invention. The exemplary optical transceiver system  200  includes a digital signal processor (DSP)  240 , a processor interface  250 , an external interface  260 , a power supply  270 , and optical transceiver interfaces  280   1 - 280   K .  
         [0020]     The DSP  240  is coupled to external optical transceivers  210   1 - 210   N  on the line side of the optical transceiver system  200  via bi-directional lines  215   1 - 215   N . The DSP  240  is also coupled to the processor interface  250  via a bi-directional line  245  and also coupled to the optical transceiver interfaces  280   1 - 280   K  via bi-directional lines  275   1 - 275   K .  
         [0021]     The power supply  270  may be coupled to the DSP  240 , optical transceiver interfaces  280   1 - 280   K , and the processor interface  250  via (dashed) lines  265 . The power supply  270  may be coupled to the external interface  260  via a bi-directional line  275 . The external interface  260  may be coupled to the processor interface  250  and the power supply  270  via bi-directional lines  255 .  
         [0022]     In operation, multiple signals from the optical transceivers  210   1 - 210   N  ingress or egress the line side of the optical transceiver system  200  via lines  215   1 - 215   N . The signals on the lines  215   1 - 215   N  may be transmitted and/or received by the optical transceiver system  200  and may be formatted according to SONET, ATM, etc. or according to any known or future developed information transport protocol.  
         [0023]     In the optical transceiver system  200 , the signals on lines  215   1 - 215   N  are processed by the DSP  240 , as desired. The DSP  240  performs processing operations on one or more of the forwarded/received signals including, for example, error correction, pre-emphasis, dispersion compensation, optical adaptation, overhead processing, interlacing, de-interlacing, control operations, etc.  
         [0024]     The DSP  240  may facilitate various synchronization modes for a TDM configuration, with respect to the signal(s) on lines  215   1 - 215   N  or  275   1 - 275   K . For example, the DSP  240  may synchronize the signal(s) on lines  215   1 - 215   N  with a local clock (not shown), or a dock recovered from one of the signal(s) on lines  215   1 - 215   N , or an external clock (not shown) via, for example, the external interface  260 . Once a clock has been selected, the data streams or signals on lines  215   1 - 215   N  can be synchronized to the selected clock. The above operation may similarly be performed for signals on lines  275   1 - 275   K .  
         [0025]     It should be understood by one of ordinary skill that the DSP  240  may be represented by any combination of one or more programmable or special purpose computing devices such as, for example, microprocessors, micro-controllers, transputers, ASIC, PLD, PLA, FPGA&#39;s, sequential or parallel computing devices, etc. that is capable of manipulating data. Additionally, the plethora of digital signal processing systems or functions that digital signal processing can perform are well known in the art and, therefore, are not elucidated in any further detail. Thus, it should be apparent to one of ordinary skill that digital signal processing methods or systems for incorporation into the invention are not limited to the examples or functions provided above.  
         [0026]     Signals processed by the DSP  240  are bi-directionally transmitted, as desired, to the processor interface  250  via the line  245  for processing by an optional secondary processor (not shown). The optional secondary processor (not shown) may be incorporated into the processor interface  250 . That is, the processor interface  250  may simply be an interface for mating or connecting the optional secondary processor. Additionally, signals from the processor interface  250  may be bi-directionally transmitted to the DSP  240  for additional or independent processing, as desired. Therefore, the processor interface  250  may accommodate interlacing operations and/or de-interlacing operations on the signals, as desired, as well as any function capable of being performed by the DSP  240 . Thus, load sharing or task sharing between the DSP  240  and the processor interface  250  may be performed.  
         [0027]     The processor interface  250  may also operate as a signal conditioning or buffering device, permitting the signal on line  245  to be processed by an external system (not shown), connected to the external Interface  260 .  
         [0028]     The power supply unit  270  supplies power, as needed, to any device connected to the external interface  260 . Therefore, the power supply unit  270  may optionally provide power in any combination of a steady state, variable, or pulse form to the DSP  240 , processor interface  250 , etc., or to any device (not shown) connected to the external interface  260 . The power supply unit  270  may incorporate signal or power filtering capabilities, for example, for reducing external or internal power noise. Additionally, control of the power supply unit  270  may be accomplished by any of the devices connected to it as well as by control signals from an external controller (not shown) connected to the external interface  260 .  
         [0029]     The external interface  260  may take the form of an electrical connector and facilitate the transfer of data or control signals via line  275  to and from the processor interface  250  to any device (not shown) connected to the external interface  260 . The external interface  260  also may accommodate the delivery of external feeds, add/drop links, clock synchronization signals, temperature compensation signals, data buses, and optical transceivers, etc., for example.  
         [0030]     Of course, it is appreciated by one of ordinary skill that the advantages provided by incorporating an external interface  260 , as in the present optical transceiver system  200 , is not limited to the examples provided above, as innumerable devices or systems may be mated to an appropriately configured external interface  260 . Any such device or system may include any of the components or system(s) already described above or any other device or system suitable for operation with the optical transceiver system  200 . For example, an external controller (not shown) may be connected to the external interface  260  and provide controlling functions for any of the devices of the optical transceiver system  200  connected directly or indirectly to the external interface  260 .  
         [0031]     In addition to the signals conveyed via line  245 , between the DSP  240  to the processor interface  250 , additional signals to and from the DSP  240  may be conveyed over lines  275   1 - 275   K  to optical transceiver interfaces  280   1 - 280   K . The optical transceiver interfaces  280   1 - 280   K  may contain optical transceivers (not shown) or may be connected to external optical transceivers (not shown) to provide independent processing, operation and controlling of access, etc. to separate client-side optical line layer(s),  285   1 - 285   K , for example. The DSP  240  may interlace or de-interlace the processed signals from lines  215   1 - 215   N  onto lines  275   1 - 275   K , or vice versa. Optionally, the optical transceiver interfaces  285   1 - 285   K , individually or corporately, may interlace or de-interlace the signals on line(s)  275   1 - 275   K  onto lines  285   1 - 285   K .  
         [0032]     Due to the modularity inherently available in using an optical transceiver interface, versus an optical transceiver, the optical transceiver interfaces  280   1 - 280   K  may separately accommodate Wavelength-Division-Multiplexing (WDM) capabilities by incorporating, such as, for example, WDM transceivers for WDM multiplexing in a client-side downstream or upstream path.  
         [0033]     Accordingly, the provision(s) for an external interface  260 , with a processor interface  250  and the transceiver interfaces  280   1 - 280   K , multiple modes for interfacing various systems as well as client-side processing can be accommodated in a convenient single module system.  
         [0034]      FIG. 2  is a block diagram of the exemplary embodiment shown in  FIG. 1  operating with a multi-gigabit physical layer capacity. Particularly, the embodiment of  FIG. 1  is adapted to support an OC192 layer capable of sustaining a 9.6 gigabits per second (Gbps) data rate.  
         [0035]     System  300  contains an exemplary optical transceiver system  350 , an external controller  390 , a client layer  395 , and a physical line OC192 layer  305  connected to a plurality of OC48 (2.4 gigabit capable) bi-directional optical transceivers  301   1 - 301   4 , shown in this example as having four optical transceivers. It should be appreciated that while  FIG. 2  illustrates four optical transceivers  301   1 - 301   4 , this embodiment may employ more or less optical transceivers, as desired.  
         [0036]     In operation, optical signals communicated over the OC192 layer  305  are transceived by the OC48 optical transceivers  301   1 - 301   4  into electrical data signals. The transceived electrical data signals are communicated to the optical transceiver system  350 , via bi-directional lines  310   1 - 310   4 . The optical transceiver system  350  operates on the signals to perform any one or more of numerous functions that comport with the capabilities and description provided herein for the optical transceiver system described in  FIG. 1 .  
         [0037]     The processed signals may be re-transmitted over lines  310   1 - 310   4  and/or communicated over lines  385   1 - 385   2  to the client layer  395 . The optical transceiver system  350  may be controlled by the controller  390 , via line  361 , to provide external clocking information, traffic flow monitoring, etc. It should be appreciated by one of ordinary skill that the list of operations that can be performed by the controller  390  are considerable. Therefore, one of ordinary skill should recognize that innumerable other examples of externally controlling or communicating with the optical transceiver system  350  are available and, thus, the scope of the invention is not limited to the examples provided above.  
         [0038]     It is emphasized that the above-detailed examples are intended only to be exemplary and not limiting. Accordingly, various modifications may be made to the system without departing from the spirit and scope of the invention. For example, each of the lines coupling the various devices in  FIGS. 1-2  may comprise several lines, either in parallel or series, or mixed in form. Also, while  FIG. 1  illustrates a single processor interface  250 , connected to the DSP  240  by a single, bi-directional line  245 , multiple processor interfaces or DSPs may be utilized in a master-slave configuration or in a parallel configuration. Additionally, the exemplary optical transceiver systems may be implemented in series or parallel having communication/processing buses between the systems. That is, for example, the controller  390  of the system in  FIG. 3 , may bridge additional exemplary optical transceiver systems (not shown).  
         [0039]     Further, while  FIG. 1  illustrates the invention as containing separate optical transceivers  210   1 - 210   N  and the power supply unit  270 , one of ordinary skill could arrange the optical transceivers  210   1 - 210   N  (or a subset thereof) and/or the power supply unit  270 , to be situated internally or externally from the system, as desired. Similarly, one of ordinary skill could incorporate or arrange the various components of the invention to increase or decrease the number of discrete components. As an illustrative example, the power supply unit  270  may be integrated into the processor interface  250 , as desired, etc.  
         [0040]     Therefore, while this invention has been described in conjunction with the specific embodiments discussed above, it is evident that many alternatives, modifications and variations will be apparent to those of skill in the art.