Ciena

About: Ciena is a company organization based out in Hanover, Maryland, United States. It is known for research contribution in the topics: Signal & Node (networking). The organization has 1259 authors who have published 1557 publications receiving 25989 citations.

System and method for enhancing the activation of DSL service

Abstract: A system enhances automation of activating network service between a customer modem and a central office modem over a digital subscriber line (DSL) link. The central office modem couples the customer modem to a network for providing the network service. The system comprises a polling system coupled with the central office modems. The polling system polls inactive central office modems in order to detect the presence of an associated customer modem. A discovery application is coupled with the polling system and the central office modems for selectively enabling ones of the central office modems in accordance with a result of the polling system. If the polling system detects the presence of the customer modem, the associated central office modem is enabled for providing network service to a customer.

Constrained continuous phase modulation and demodulation in an optical communications system

Abstract: A transmitter in an optical communications system includes a digital signal processor for processing a data signal to generate a sample stream encoding successive symbols in accordance with a constrained phase modulation scheme having a constellation of at least two symbols and a modulation phase constrained to a phase range spanning less than 4π. A digital-to-analog converter converts the sample stream into a corresponding analog drive signal. A finite range phase modulator modulates a phase of a continuous wavelength channel light in accordance with the analog drive signal, to generate a modulated channel light for transmission through the optical communications system. A receiver in the optical communications system includes an optical stage for detecting phase and amplitude of the modulated channel light and for generating a corresponding sample stream, and a digital signal processor for processing the sample stream to estimate each successive symbol of the modulated channel light.

Clock recovery from an optical signal with dispersion impairments

Abstract: A method of recovering a clock signal from an optical signal received through an optical communications system. A digital sample stream is processed to generate a dispersion compensated signal. The dispersion compensated signal is then tapped to obtain upper side band and lower side band signals of each received polarization of the optical signal. The upper side band and lower side band signals are then processed to compensate polarization dependent impairments, and the clock recovered from the resulting optimized.

Span management system for wavelength division multiplexed network

Abstract: The present invention is directed to an optical network management system in which each network element exchanges identification and status information for performing various monitoring and control functions in the optical network. A network communication system comprising an optical communication path and a plurality of network elements disposed along the optical communication path. A first network element coupled to the optical communication path includes a first processor and a first optical component. The status of the first optical component being monitored by the first processor. The first processor generates a first electrical signal in accordance with the status of the first optical component. The first network element also includes a service channel transmitter coupled to the first processor and emits a second optical signal to the optical communication path at a second wavelength different than the first plurality of wavelengths in response to the first electrical signal. The second optical signal being modulated in accordance with the second electrical signal. A second network element is coupled to the optical communication path and includes a second processor, and second optical component coupled to the second processor and a service channel receiver coupled to the first processor and to the optical communication path. The receiver senses the second optical signal. The service channel receiver outputs a second electrical signal to the second processor in response to the second optical signal. The second processor controls the second optical component in response to the second electrical signal.

Fabry-perot optical filter and method of making the same

Abstract: An optical filter having broad resonant frequency passbands for filtering an optical input including a plurality of multiplexed optical wavelengths into a first set of transmitted wavelengths and a second set of reflected wavelenghts. The filter has first and second inner mirrors separated substantially by an inner spacer, a first outer mirror separated from the first inner mirror substantially by a first outer spacer, and a second outer mirror separated from the second inner mirror substantially by a second outer spacer. The inner mirrors have reflectivity which is greater than the reflectivity of the outer mirrors, and are formed from layers of alternating high and low refractive index materials. The optical thicknesses of the spacers are substantially identical, and are sized to align the resonant frequency passbands of the filter with the first set of transmitted wavelengths. A method of making the filter using solid spacer(s) is disclosed wherein a plurality of spacers are formed from a single wafer of material. Also disclosed is a method of making a filter wherein the interfaces between filter segments are within the inner mirrors of the filter.