Abstract: A method for detecting defects in an optical device. The method includes obtaining an optical device that is a component of an optical communications system carrying information signals at a communications wavelength. Infrared light is applied to the optical device. The infrared light has a wavelength corresponding to the communications wavelength. An image of the optical device is obtained while the optical device is transmitting the infrared light. The image provides multidimensional data including positional values and intensity values. The image is then analyzed to detect defects in the optical device.

Abstract: A module housing apparatus protects modules having sensitive electrical, optical, and/or electro-optical components from physical and electrostatic discharge (ESD). The module housing apparatus includes a box constructed or coated with a conductive material and having an open end. Module board guides are formed in opposing inside surfaces of the conductive box and include slots that accept and guide the board edges of the module. The conductive module faceplate mates with the conductive box to form a Faraday cage that protects the components of the module from ESD. The module board guide may be modified to accept the module faceplate inner profile including, for example, a recess that accepts a module holding clip and/or an insertion guide to guide the board edges into the slot. A retaining mechanism such as a strap may be used to hold the module in the housing.

Abstract: An optical fiber ring is provided carrying a plurality of WDM optical signals, each at a respective one of a plurality of wavelengths. Each optical signal carries data associated with a corresponding group of TDM add/drop multiplexers coupled to an optical path spaced from the optical fiber ring. The optical signals are extracted from the fiber ring with optical add/drop multiplexers, and the data carried by the optical signals is then supplied to the corresponding group of TDM add/drop multiplexers. Accordingly, instead of assigning an optical add/drop multiplexer to each TDM add/drop multiplexer, the optical add/drop multiplexers are assigned to respective groups of TDM add/drop multiplexers. As a result, optical loss as well as cost of the WDM ring are minimized.

Abstract: At least one protection line is shared among SONET rings. Identification and availability information of the shared protection line is distributed among the switches of the SONET rings using K-byte data in the SONET overhead.

Abstract: An apparatus that mass polishes a variety of fiber optic cable connectors simultaneously. The apparatus includes a plurality of polishing plates, each capable of holding its own polishing film and pad, and having a varying height. The apparatus further includes a plurality of connector fixtures that may receive a variety of connectors at varying angles. Each connector fixture communicates with a corresponding polishing pad. Thus, fiber optic cable connectors having a variety of polished end faces may be provided with the apparatus. The apparatus also eliminates the potential for contamination among polishing films, reduces polishing steps, and saves labor and maintenance costs.

Abstract: A fiber optic cable saddle for securing and routing fiber optic cables on a printed circuit board (PCB) or other component used in the communications field. The fiber optic cable saddle includes a body portion that may be connected to a post having a barb at one end. The saddle may be mounted in a PCB by forcing the barb in an opening provided in the PCB. The fiber optic cable saddle is formed from a soft, resilient material that permits the body portion to flex open and return back to its original shape. The profile of the body portion is a thin, closely spaced spiral. Each of the free ends of the body portion has a cylindrical projection integrally formed thereon. In a closed position of the saddle, the cylindrical projections are partially disposed within corresponding recesses formed in the body portion. Before securing the fiber optic cables within the saddle, a user will preferably mount the saddle on the PCB.

Abstract: A method and apparatus for generating massive interrupts in random access memory (RAM) are provided, comprising receiving and storing Time Slot network (TS Net) data frames comprising switching event information in a first RAM area. Compare operations are performed among prespecified ones of the TS Net data frames. Unit interrupt bits are set in a corresponding location of a second RAM area in response to detected bit differences resulting from the compare operations. Interrupt status bits are set in a corresponding location of a third RAM area in response to set unit interrupt bits. Massive interrupt signals are generated in response to set unit interrupt bit.

Abstract: A frequency of an ultrasonic cleaner for cleaning an optical fiber can be varied, thereby facilitating removal of particles of various sizes. The control of the varying may be predetermined or may be closed loop. The control may also alter the duration of the application of the frequency. A container which insures a set position of the fiber and/or immersion of the fiber in a cleaning solution may be employed. The sizes of particles on the fiber to be cleaned may be determined and parameters for cleaning may be selected in accordance with the determined sizes.

Abstract: A method for operating a redundant optical communication network has at least two network transmission paths, assigns first and second protection protocols to switched signals and secondary signals respectively, adds and drops the switched signals and secondary signals on the at least two network transmission paths, makes the switched signals and the secondary signals to counter-propagate along the at least two network transmission paths, therefore, the redundant optical communication network can support different data types and different protection mechanisms.

Abstract: The invention includes a method for controlling amplifier output power in an optical communications network. A first transmission parameter is determined at a first amplifier. In an exemplary embodiment, the first transmission parameter is a composite express signal to noise ratio. The total output power of a downstream amplifier is adjusted in response to the first transmission parameter. A system for implementing the method is also disclosed.

Abstract: An optical filter including a plurality of dielectric layers is provided between first and second substrates. The substrates have a coefficient of thermal expansion that is greater than that of the dielectric layers, and the thicknesses of the substrates are selected to provide compensation for temperature-dependant variations in the center wavelength of the filter. A variety of substrate materials may be used. Quartz is advantageous as a substrate material because it has relatively low loss at wavelengths commonly used in telecommunication systems. Moreover, it is thermally and chemically stable, and has good adhesion to most dielectric films used as quarter and half wave layers. Further, quartz is mechanically tough, relatively inexpensive and readily available. The quartz substrate is cut from a crystal and has an orientation with reduced birefringence.

Abstract: The invention includes a method for controlling amplifier output power in an optical communications network having channel add/drop capability. A first transmission parameter and a second transmission parameter are determined at a first amplifier. In an exemplary embodiment, the first transmission parameter is a composite express signal-to-noise ratio and the second transmission parameter is a composite signal-to-noise ratio. The total output power of a downstream amplifier is adjusted in response to the first transmission parameter and second transmission parameter. A system for implementing the method is also disclosed.

Abstract: A clock signal is received. A synchronization signal is compared to the clock signal to determine whether the synchronization signal is asserted within a predetermined period of time with respect to clock signal cycles. The synchronization signal assertion is used to synchronize a circuit to an external event, if the synchronization signal assertion is received within the predetermined period of time. If the synchronization signal assertion is not received within the predetermined period of time the circuit is not synchronized.

Abstract: An apparatus for managing and measuring fiber optic cable includes a mounting base for receiving and retaining a variety of fiber cassettes capable of holding optical components having fiber optic cables emanating therefrom. The apparatus includes a pair of interchangeable marking mandrels spaced from the fiber cassette and having circumferences that exceed the minimum bend radius of the fiber optic cables. Each marking mandrel has marking grooves formed on its periphery so that the fiber optic cable may be marked at a predetermined location for future splicing of the cable. The apparatus further includes fiber take up mandrels connected to the mounting base, each fiber take up mandrel having a circumference that exceeds the minimum bend radius of the fiber optic cables. The marked fiber optic cables may be temporarily wound around the circumference of the fiber take up mandrels to prevent entanglement and keep the fiber out of the operator's way while another cable is being marked.

Abstract: A system for calibrating a plurality of optical modules includes a plurality of optical signal sources and optical signal degradation elements optically communicating with input switches. The input switches supply optical test signals to optical modules (units under test) plugged into a common shelf. Calibration switches including variable optical attenuators may be used to adjust the input signal levels and alternately supply adjusted signals to an optical power meter and the units under test. A controller is used to control the adjustment and thereby provide defined, measured signal levels to the units under test. By reading data from the units under test and using these defined signal levels, the optical modules may be calibrated or diagnosed. Output optical switches are used in a similar fashion to calibrate or diagnose the outputs of the units under test. In addition to input/output power calibration, the invention may also perform wavelength calibrations.

Abstract: A connect and disconnect assembly for connecting and disconnecting a laser diode having leads to a printed circuit board (PCB). The assembly includes a heatsink that connects with the printed circuit board by providing cap screws through the PCB which are threadably received in spacers connected to the heatsink. A connection assembly made up of a retainer block and screws connects the laser diode to the heatsink. The laser diode is provided through a cutout portion of the PCB, and connects to the heatsink by providing the screws through the retainer block and the laser diode, the screws being threadably received in the heatsink. A pair of fuzz button carriers are interposed between the laser diode and the PCB. Each fuzz button carrier has a body portion, spaced guide portions extending above the body portion, and fuzz buttons extending through the body portion.

Abstract: The invention includes a method for determining channel power in an optical communications network. The method includes determining at least one transmission parameter for a channel. Exemplary transmission parameters include transmission rate and transmission format. A number of channel units is determined in response to the transmission parameter. Channel power is then determined for the channel in response to the number of channel units. A system for implementing the method is also disclosed.

Abstract: A system detects potentially dangerous conditions, prevents damage to optical components, and prevents humans from being physically harmed by stray pumping light. Optical systems employing distributed amplification such as Raman amplification utilize pumps having high output powers. These high output powers create dangerously high power densities in the optical fiber. If a connection is imperfect a hot spot may develop and the connection damaged by the pumping light. Fiber damage, disconnections and component degradations or failures may also permit the pumping light to escape the intended path and cause physical harm to humans as well as equipment. Pumping light backreflections caused by such imperfect connections, degraded/failed components, and fiber damage are detected. A controller compares the backreflection amount against a threshold to determine whether a precautionary measure should be taken such as shutting down the pump, decreasing pump power to a safe level or setting a maintenance flag.

Abstract: An apparatus and method are provided for monitoring the Q-factor of a plurality of main signals that are simultaneously transmitted across a fiber optic line using wave division multiplexing. In particular, the includes an optical tap, a tunable optical bandpass filter, and a Q-detection circuit. The optical tap operates to tap the fiber optic line to provide a plurality of tapped signals corresponding to the plurality of main signals. The tunable optical bandpass filter acts to select one of the plurality of tapped signals, by only passing a selected signal in a chosen channel frequency band. The Q-detection circuit then determines the Q-factor of the selected signal. This operation can be performed sequentially for each of the plurality of tapped signals to provide a measure of the Q-factor for each of the plurality of main signals. This operation can also be continually repeated to provide a constant measurement of the Q-factor of each of the plurality of main signals.

Abstract: An exemplary embodiment of the invention is a Raman amplifier for use in an optical communications network. The Raman amplifier includes a plurality of pump lasers and a plurality of wavelength control modules, each associated with one of the pump lasers. Each wavelength control module includes a fiber Bragg grating optically coupled to a respective one of the plurality of pump lasers. The fiber Bragg grating receives a pump laser output from one of the pump lasers and generates a wavelength control module output. A temperature sensor is in thermal contact with the fiber Bragg grating and generates a temperature signal indicative of a temperature of the fiber Bragg grating. A controller is operatively connected to the temperature sensor and generates a control signal in response to the temperature signal. A thermal regulator is in thermal contact with the fiber Bragg grating and adjusts the temperature of the fiber Bragg grating in response to the control signal.