摘要:
An optical communications system is adapted for connection to an optical fiber link of an optical communications network. The system obtains a fiber identifier respecting the optical fiber link; a respective optimum setting of one or more parameters of the optical communications system; and adjusts a respective value of each parameter in accordance with the respective optimum setting. The fiber identifier can be obtained from a value of at least one fiber transmission property of the optical fiber link. The fiber transmission property value is used to search a look-up table of class definitions, each class definition including a respective class identifier and at least one corresponding characteristic transmission property value. A class identifier is selected as the fiber identifier from the class definition for which each characteristic transmission property value most closely matches a corresponding fiber transmission property value. Each class definition may also include an optimum setting for each parameter.
摘要:
A digital instruction is generated regarding one or more electrical-to-optical conversion impairments induced at the transmitter of an optical communication system. The digital instruction may be used by the transmitter to reduce the impairments. Alternatively, or additionally, the digital instruction may be used by the receiver of the optical communication system to compensate for the impairments.
摘要:
Optical dispersion imposed on a communications signal conveyed through an optical communications system is compensated by modulating the communications signal in the electrical domain. A compensation function is determined that substantially mitigates the chromatic dispersion. The communications signal is then modulated in the electrical domain using the compensation function. In preferred embodiments, compensation is implemented in the transmitter, using a look-up-table and digital-to-analog converter to generate an electrical predistorted signal. The electrical predistorted signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system.
摘要:
A method of processing a stream of digital samples of an optical signal received by a coherent optical receiver. The digital sample stream is processed to generate a dispersion compensated sample stream. The dispersion compensated sample stream is then processed to compensate polarization dependent impairments of the optical signal.
摘要:
Laser line-width compensation is performed by detecting noise in an optical signal output by a laser of an optical communications system and controlling a complex modulator to cancel the detected noise. Line-width compensation can be performed for both amplitude and phase noise in the optical signal. Noise measurements are used to compute a complex scalar. The complex scalar is used by a compensation processor to modify an input signal that is to be transmitted by the optical communications system. The modified input signal controls the complex modulator, which modulates the output signal to cancel the noise.
摘要:
An optical spike is generated at an arbitrarily selected location within an arbitrary optical link. The optical spike is generated by deriving a spike signal having a plurality of components, and launching the spike signal into the a transmitter end of the optical link. An initial phase relationship between the components is selected such that the involved signal components will be phase aligned at the selected location. In order to achieve this operation, the initial phase relationship between the components may be selected to offset dispersion induced phase changes between the transmitter end of the link and the selected location. One or more optical spikes can be generated at respective arbitrarily selected locations within the link, and may be used for performance monitoring, system control, or other purposes.
摘要:
An optical spike is generated at an arbitrarily selected location within an arbitrary optical link. The optical spike is generated by deriving a spike signal having a plurality of components, and launching the spike signal into the a transmitter end of the optical link. An initial phase relationship between the components is selected such that the involved signal components will be phase aligned at the selected location. In order to achieve this operation, the initial phase relationship between the components may be selected to offset dispersion induced phase changes between the transmitter end of the link and the selected location. One or more optical spikes can be generated at respective arbitrarily selected locations within the link, and may be used for performance monitoring, system control, or other purposes.
摘要:
Accelerated protection switching in a multi-platform network switch may be achieved by allocating connectivity slots from the port cards to the switch cards for all states of a connection through the switch and forming maps of the allocations for use by the port cards and switch cards. By allocating connectivity slots to all states of the connection, the connection will not be blocked in connection with a state change. By storing the slot allocation in maps a connection state change may be implemented by the switch by causing traffic on the connection to be transported using the allocated slots. Various protection modes can use the same connectivity slots with collision avoidance via prepared maps Thus, having predefined paths via allocated slots provisioned through the network element enables the network element to switch very quickly from working to protection to comply with applicable standards and minimize disruption of network traffic.
摘要:
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 sand lower side band signals are then processed to compensate polarization dependent impairments and the clock recovered from the resulting optimized.
摘要:
A stent graft system for intraluminal deployment in an aorta and a branch vessel that includes an aorta stent graft for deployment within the aorta and defining a lumen for the passage of blood therethrough, and having a fenestration positioned and sized so as to allow blood to flow to a contiguous branch vessel. The system also includes a branch vessel prosthesis, preferably a stent graft, having a tubular portion and a flaring portion, such that, when deployed, the flaring portion is located within the lumen of the aorta stent graft and the tubular portion passes through the fenestration and into the branch vessel. A balloon expansion catheter expands the tubular portion and flare the flaring portion. The expansion of the tubular portion and the flaring of the flaring portion may occur sequentially or simultaneously.