Abstract: A method and apparatus for amplifying an optical signal in an optical network is provided. In an embodiment of the present invention, an optical amplifying module is disclosed for use in an optical network. The optical amplifying module comprises a variable optical attenuator (VOA), an optical amplifier and a controller. The VOA, optical amplifier and controller are coupled to each other and the optical network. The VOA attenuates the optical input signal to produce an attenuated output signal. The optical amplifier amplifies the attenuated output signal to produce an amplified output signal. The controller receives network operating parameters and also monitors the power levels of the attenuated and amplified signals. Based on the measured power levels and the received operating parameters, the controller adjusts the VOA such that the optical output power per channel is maintained at a constant value.

Abstract: To improve a power balance of an optical add multiplexer, an add amplifier is optically coupled to an add path of an optical add module. A through loss associated with a signal passing through the add module, and an add loss associated with a signal travelling an add path of the add module are known or otherwise calibrated values. An input power measurement of the signal input to the add module is used in conjunction with the through loss, add loss, and number of added channels to determine an add path amplification value. The gain of the add amplifier is controlled according to add path amplification value so that the power level of added channel(s) substantially matches the power level of the WDM signal output from the add multiplexer. Furthermore, the gain profile of the add amplifier preferably matches a gain profile of a signal input to the add module.

Abstract: An embodiment of the invention is a method of allocating protection path resources including defining a working path and obtaining a link vector for each of a plurality of protection paths. The link vector includes a plurality of link vector elements. A proposed link vector is determined for each of the protection paths. The proposed link vector includes a plurality of proposed link vector elements and is indicative of allocating a respective protection path to the working path. A maximum link vector element is determined and a maximum proposed link vector element is determined. A link cost is determined based on a difference between the maximum proposed link vector element and the maximum link vector element. A path cost is determined for at least two protection paths based on a sum of link costs associated with a respective protection path. One of the at least two protection paths having the minimum path cost is selected to provide protection for the working path.

Abstract: A three stage optical amplifier is disclosed having a substantially flat gain profile. The amplifier includes a variable optical attenuator coupled between second and third stages of the amplifier and a dispersion compensating element. The attenuation of the optical attenuator is adjusted in accordance with the loss across dispersion compensating element and the optical power input to the amplifier to thereby obtain a substantially flattened gain profile. An offset value can also be used to refine the variable optical attenuator control and minimize nonflatness. The first and second stages are preferably pumped to provide high gain and a low noise figure and the third stage is preferably pumped to provide a high optical conversion efficiency. In an additional example, received optical powers associated with each of the channels in a WDM system are monitored and the attenuators within each amplifier in the system are controlled so that the received powers are substantially equal.

Abstract: A system and method for staggering the starting of embedded system modules of an optical node is disclosed. The embedded system modules of an optical node may be communicatively coupled to a shared data resource required by the embedded system modules during a start/restart. The message traffic associated with the embedded system modules accessing the shared data resource is beneficially distributed by staggering the start process of each of a plurality of embedded system modules over a pre-selected time range.

Abstract: To improve a power balance of an optical add/drop multiplexer, an add amplifier is optically coupled to an add path of an optical add/drop module. A through loss associated with a signal passing through the add/drop module, a drop loss associated with a signal travelling a drop path of the add/drop module, and an add loss associated with a signal travelling an add path of the add/drop module are known or otherwise calibrated values. A dropped channel power measurement is used in conjunction with the through loss, add loss, drop loss, number of dropped channels and number of added channels to determine an add path amplification value. The gain of the add amplifier is controlled according to add path amplification value so that the power level of the added channel(s) substantially matches the power level of the WDM signal output from the add/drop multiplexer. Furthermore, the gain profile of the add amplifier preferably matches a gain profile of a signal input to the add/drop module.

Abstract: An optical receiver configuration and method of controlling an optical signal receiver adjusts a decision threshold to reduce the bit error rate (BER). The receiver includes a comparator having a data input and a digital data output. An error detection & correction circuit provides an error signal representative of the number of corrected “1”s and “0”s in the data output from the comparator. Based on the error signal, a control circuit modifies the comparator decision threshold in a direction to reduce the BER of the receiver. Dynamic modification of the decision threshold may also be accomplished. A total percentage error indicator is preferably used as the basis of changing the decision threshold value. The total percentage error indicator may be used to variably adjust the decision threshold by an amount that varies according to the magnitude of the total percentage error indicator to thereby more quickly arrive at an acceptable decision threshold and prevent overshoot.

Abstract: In a ring having first and second adjacent nodes, and two fibers carrying information between the first and second nodes, the first fiber carries information in one direction, while the second fiber carries information in another direction. Each fiber includes wavelength capacity allocated to working and protection traffic. The working and protection wavelength capacities in the first fiber are respectively assigned to first and second disjoint sets of wavelengths, while the working and protection wavelength capacities in the second fiber are respectively assigned to the second and first disjoint sets of wavelengths.

Abstract: A tool kit for servicing a telecommunications device that utilizes pin connectors connecting electronic modules to the backplane. The tool kit includes one or more pin insertion tools for inserting new pins into pin connectors disposed on the backplane. One or more guide shrouds attachable to the backplane which isolate specified portions of the backplane to make pin insertion easier. The head of the pin insertion tool is preferably fittable into the frame of the shroud. Preferably, all of the components of the tool kit are asymmetric so that only one pin insertion tool may be fitted into only one shroud in only one orientation, to insure proper pin placement.

Abstract: An optical receiver configuration and method of controlling an optical signal receiver adjusts a decision threshold to reduce the bit error rate (BER). The receiver includes a comparator having a data input and a digital data output. An error detection & correction circuit provides an error signal representative of the number of corrected “1”s and “0”s in the data output from the comparator. Based on the error signal, a control circuit modifies the comparator decision threshold in a direction to reduce the BER of the receiver. Dynamic modification of the decision threshold may also be accomplished. A relative percentage error indicator is preferably used as the basis of changing the decision threshold value. The relative percentage error indicator may be used to determine how much to adjust the decision threshold at each iteration of the method to more quickly arrive at an acceptable decision threshold and prevent overshoot.

Abstract: A semi-transparent time division multiplexer/demultiplexer that transmits low rate tributaries from one location to another using a high rate aggregate connection, while preserving substantially all of the TOH and payload for each tributary signal. Transparency of the tributary TOH is accomplished by interleaving both the TOH and the Payload of each tributary into the high rate aggregate signal. Some TOH bytes may be tunneled or re-mapped into unused/undefined TOH locations in the aggregate signal to allow transparency of the TOH without corrupting the aggregate. Errors may be handled by tunneling BIP bytes into unused/undefined aggregate locations and updating the tunneled bytes with error masks calculated at each network elements. Alternatively errors may be forwarded by using an error mask generated from the tributary BIP locations and inserting the mask into the associated aggregate BIP locations. The mask in the aggregate BIP is updated with error masks calculated at each network elements.

Abstract: A defect management system and method includes a centralized database operatively connected to operator, troubleshooter, reworker and inspector workstations via a network. A defect information management application program is installed on the workstations and generates graphical user interfaces that permits the operator, troubleshooter, reworker, and inspectors to log and coordinate defect information. Modules being manufactured may exhibit symptoms of a defect. The symptom and symptom category are logged into the database by the operator. A troubleshooter reviews the logged symptom information to aid in the diagnosis and entry of defect category and defect information. The symptom and defect information are associated with various processes and process steps to accurately track defect module information. A reworker reviews the logged symptom and defect information to determine appropriate repairs. Repair action categories and repair actions are then logged by the reworker.

Abstract: A method for routing network switching information includes generating at one Time Slot Network (TS Net) data firame from at least one data frame of a first type. The TS Net data frame comprises switching event information. The TS Net data frame is transferred and stored among a number of network elements using a backplane network. Compare operations are performed among prespecified data frames of the TS Net data frame, and at least one interrupt signal is generated in response to detected changes resulting from the compare operations. Information routing is controlled in at least one network and the associated network elements in response to the interrupt signals.

Abstract: Faceplate, energy-attenuating, waveguide extensions are provided for use with an optical communications module having a circuit board. The circuit board has a plurality of transceivers adjacent to corresponding openings in a front portion of a faceplate, outside a protective zone of a Faraday cage created by the faceplate and adjacent modules, exposing the transceivers to electrostatic discharge (ESD), electromagnetic interference (EMI) or other destructive energy created by the faceplate openings. To attenuate the ESD, EMI, or other energy emanating through the faceplate openings, an integral, waveguiding, snout-like extension (or protrusion) is provided around the periphery of each of the faceplate openings. A removable waveguide extension to the snout-like extension may also be provided to further attenuate ESD, EMI or other energy. The longer the waveguide created by the combined removable extension and the integral snout-like extension, the greater the ESD, EMI, or other energy attenuation.

Abstract: A method of improving the quality of manufactured modules includes logging manufacturing information to a database and utilizing a knowledge base to determine defects of a manufactured module. A quality ticket is issued for defective modules that is used to log and store defect symptom information in the database. Defects may be determined based on the quality ticket and by utilizing the knowledge base. Repair suggestions may be made and logged to the quality ticket based on the defect determination. Repairs are performed and repair actions logged to the quality ticket. Tests are then performed on the repaired modules. Based on the test results, the knowledge base is updated. In other words, the knowledge base learns over time as more modules, symptoms, defects and actions are tracked. The knowledge base aids during troubleshooting by providing a list of repair actions and frequency of such repair actions that successfully repaired the defect identified in the quality ticket.

Abstract: A system and method for automatically generating a protection route as an alternative to a working route through a network of switches prior to network failure. A switch selects the proposed protection route so that the protection route is disjoint from the working route. Next, a switch or switches determines whether bandwidth is available for the proposed protection route. If so, the protection route is set-up for activation when needed.

Abstract: A memory management system, method and computer readable medium for use in a circuit pack or circuit card such as in a node in an optical network are described. The memory management system includes memory that provides persistent storage over a reboot and a memory manager for directly controlling access to the reboot persistent memory. The memory manager processes requests received from one or more applications executing on the circuit card for storage of a set of data. The request indicates during which type of reboot, cold or warm, the data is to be received and may also indicate a particular state during a reboot in which the data is to be received. The manager responds to a reboot of the circuit card by providing a set of data from the reboot persistent memory to the application during the reboot.

Abstract: A frame relay (FR) protection method generates an OAM frame to other nodes upon detecting a defect on a SONET ring. The protection frame comprises a type of failure and a location of failure. A node that detected the defect transmits the protection frame to other nodes about the location of the failure and the type failure. Protection tables are provided for switching a working fiber link to a protection fiber link. A protection switching provides a method re-establish FR traffic in spite of a detected failure on a SONET ring.

Abstract: An embodiment of the invention is a network element including a monitor module for monitoring received network traffic on a uni-directional, first working link and detecting a failure in the first working link. A controller in communication with the monitor module is notified of a failure in the first working link. A mesh protection service (MPS) module is in communication with the controller. The MPS module transmits an MPS message signal using uni-directional communications. The MPS message signal identifies the first working link.

Abstract: An exemplary embodiment of the invention is an optical filter including a mirror including a plurality of first dielectric layers having a first index of refraction and a plurality of second dielectric layers having a second index of refraction. A plurality of the first dielectric layers have an integer quarter wave optical thickness and at least one of the first dielectric layers has a non-integer quarter wave optical thickness. A plurality of the second dielectric layers have an integer quarter wave optical thickness and at least one of the second dielectric layers has a non-integer quarter wave optical thickness. In an exemplary embodiment, the non-integer quarter wave optical thickness first layer and the non-integer quarter wave optical thickness second layer are determined so as to enhance transmission at a predetermined wavelength.

Abstract: Engine control apparatus for use in passenger cars and other applications includes a special calibration of the intake mixture preparation system. Although this calibration duplicates the optimum calibration for use with a continuously variable transmission (CVT), the apparatus instead includes, for reasons of practicality, a discrete-ratio powershift transmission. Also included is a feedback control system which dispenses with the conventional mechanical connection between accelerator pedal and engine throttle valve. This drive-by-wire control system operates the engine as closely as is practical to the optimum CVT engine operating schedule, a predominantly wide-open-throttle engine operating schedule. The overall combination of special engine calibration and drive-by-wire control with a discrete-ratio transmission can offer the majority of the fuel economy advantage available with a CVT.