Abstract: Techniques, apparatus and systems to provide adjustable bit rate optical transmission using programmable signal modulation in optical communication systems.

Abstract: An optical duobinary transmitter. The transmitter uses a half-rate precoder, half-rate non-linear modulation drive circuits and a multiplex modulator for generating duobinary modulation on an optical signal from which full-rate data can be detected without decoding. The intensity of the optical signal is modulated to be zero between data symbols.

Abstract: Associated with an optical transport system, a packet oriented supervisory network provides differentiated classes of service (CoS) for a plurality of WDM layer applications on diverse nodes such that as soon as a higher priority application or packet arrives, the lower priority application is affected in favor of the higher one. One or more optical control channels (OSC) are used as the physical medium for implementing the packet oriented supervisory network of the invention. This new functionality of the optical control channel (OSC) enables multiple services by allowing each application to use up to 100% of the OSC bandwidth, if no other application is using it.

Abstract: An iterative process is used to set the phase prechirp of a WDM optical transport system to a system's optimal level that maximizes the signal quality. A signal degradation factor takes into account linear and non-linear effects along the optical path and is used as a receive end feedback signal to control the phase prechirp level at the transmitter site. By using the FEC corrected errors rate as the feedback signal, optimization of signal quality is performed even when the system is running error free. By using an adaptive phase prechirp transmitter, signal degradation compensation can be also performed on a per wavelength basis to compensate for the residual dispersion slope and to allow optimization of individual channels independently of the net link dispersion value.

Abstract: An integrated OTDR/OSC mechanism for monitoring an optical transport system without disrupting the normal service. The invention combines two essential network components in an integrated mechanism. These components are the mandatory OSC function as part of any DWDM network, and the in-skin, in-service attributes of the OTDR engine. One pair of control wavelengtbs is sufficient to perform both OSC and OTDR functionalities. In this way, distributed control function, OTDR procedures, and fiber monitoring is achieved, while trace acquisition from anywhere in the network becomes possible. By bringing these two essential network components together, the invention allows for superior network management and reduction in maintenance costs. This is primarily due to the fact that the invention allows to use and control the OTDR engine remotely, while the combination with the OSC function allows rapid implementation of the OTDR procedures on operating channels within each fiber of a cable.

Abstract: An embodiment includes an admission control program of a router in a transmission system. A router includes a dither signal (a periodic timing signal) at a frequency causing the IP flow to organize into a periodic and deterministic pattern. The frequency is selected to maximize IP flow rate. Multiple, independent input paths may be combined into a single output path using the dither signal to regulate when the paths are alternately combined into the single output path.

Abstract: An embodiment includes an optical source, an optical receiver, and an interconnecting optical fiber. A data sequence is received and encoded or formatted as an IP packet using an encoding format capable of returning a signal representing the IP packet to a predetermined value at the beginning of each bit period of the IP packet at a physical layer of the network. The encoded IP packet is then transmitted directly over an optical layer of the network without adapting the IP packet to another encoding format or using an adaptation layer in the network (e.g., at a data link layer or higher). The optical receiver receives the IP packet and then a clock signal is extracted without the overhead and costs associated with additional adaptation or encoding of the IP packet.

Abstract: An integrated OTDR/OSC mechanism for monitoring an optical transport system without disrupting the normal service. The invention combines two essential network components in an integrated mechanism. These components are the mandatory OSC function as part of any DWDM network, and the in-skin, in-service attributes of the OTDR engine. One pair of control wavelengths is sufficient to perform both OSC and OTDR functionalities. In this way, a distributed control function, OTDR procedures, and fiber monitoring is achieved, while trace acquisition from anywhere in the network becomes possible.

Abstract: An embodiment includes a polarization beam splitter and a feedback unit, preferably having an autocorrelator, a processing unit and a polarization controller. Polarized splitter separates the lower-speed tributary signals out of the higher-speed optical signal based upon a polarization relationship (e.g., orthogonal) between the tributary signals. The feedback unit, typically an autocorrelator and a polarization adjustment device, adjusts the higher-speed signal's state of polarization based upon an autocorrelation value of one of the lower-speed tributary signals. The autocorrelation value of one of the lower-speed tributary signals is provided to the polarization adjustment device, which typically includes a processing unit and a polarization controller. The polarization adjustment device adjusts the higher-speed signal's polarization state based upon the autocorrelation extinction ratio value.

Abstract: Associated with an optical transport system, a packet oriented supervisory network provides differentiated classes of service (CoS) for a plurality of WDM layer applications on diverse nodes such that as soon as a higher priority application or packet arrives, the lower priority application is affected in favor of the higher one. One or more optical control channels (OSC) are used as the physical medium for implementing the packet oriented supervisory network of the invention. This new functionality of the optical control channel (OSC) enables multiple services by allowing each application to use up to 100% of the OSC bandwidth, if no other application is using it.

Abstract: A multiplexer demultiplexer for conversion of optical data between a serial bit stream having a bit rate in excess of that of conventional photodetection devices and multiple bit streams at a bit rate that may be serviced using conventional photodetection devices. A wavelength conversion element uses four-wave mixing to produce from a single high rate data stream multiple intermodulation products that together represent the input serial data stream in wavelength division multiplexed (WDM) form. A related device multiplexes multiple WDM data streams provided at conventional bit rates to a serial bit stream having a bit rate in excess of that of conventional photodetection devices.

Abstract: An iterative process is used to set the phase prechirp of a WDM optical transport system to a system's optimal level that maximizes the signal quality. A signal degradation factor takes into account linear and non-linear effects along the optical path and is used as a receive end feedback signal to control the phase prechirp level at the transmitter site. By using the FEC corrected errors rate as the feedback signal, optimization of signal quality is performed even when the system is running error free. By using an adaptive phase prechirp transmitter, signal degradation compensation can be also performed on a per wavelength basis to compensate for the residual dispersion slope and to allow optimization of individual channels independently of the net link dispersion value.

Abstract: An embodiment includes an optical source, an optical receiver, and an interconnecting optical fiber. A data sequence is received and encoded or formatted as an IP packet using an encoding format capable of returning a signal representing the IP packet to a predetermined value at the beginning of each bit period of the IP packet at a physical layer of the network. The encoded IP packet is then transmitted directly over an optical layer of the network without adapting the IP packet to another encoding format or using an adaptation layer in the network (e.g., at a data link layer or higher). The optical receiver receives the IP packet and then a clock signal is extracted without the overhead and costs associated with additional adaptation or encoding of the IP packet.

Abstract: An embodiment includes a gating device, a feedback device and a control device. Soliton pulses are received by the gating device, which detects and monitors a dispersive-wave between adjacent soliton pulses using a timing circuit. The timing circuit typically provides a gating signal offset in phase from the soliton pulses in order to trigger the gating device. Triggering the gating device allows the dispersive-wave to be accessed and monitored between adjacent soliton pulses. The feedback device, typically using detectors and processing circuitry, measures the energy of the soliton pulses and the energy of dispersive wave. The feedback determines a ratio of the energy levels as an indication of soliton-pulse transmission performance. The indication is provided to the control device as a feedback signal so that the control device can appropriately adjust characteristics of the soliton pulses and improve or optimize transmission performance.

Abstract: In a WDM transmission system carrying amplitude modulated traffic in which significant cross-phase modulation occurs, each of the individual channels is pre-chirped at the transmitter with replicas, or low-pass filtered replicas of the amplitude modulation applied to each of the other channels. Prechirping of each individual channel with a replica of the amplitude modulation applied to that channel may be added in order additionally to provide compensation for self-phase modulation.

Abstract: An optical interferometer incorporating a signal strength modulated optical phase delay, such as a Kerr effect element in one of its arms is employed to improve the cross-talk isolation/extinction ratio of an optical switch, amplitude modulator, or amplitude modulated optical transmitter. The Kerr element is constructed so that its intensity dependent optical path length is such as to provide destructive interference at the interferometer output when the light input to the interferometer is low, and constructive interference when the input is high. The place of the Kerr effect element can alternatively be taken by an electro-optic modulator driven with an electrical version of the data modulation appearing on the optical signal.