Abstract: A method and module for affecting controlled switching of optical signals having different modes of propagation, wherein the module being provided with at least two multi-mode ports MMPs and a plurality of single-mode ports SMPs, the method comprises: inputting at least one multimode optical signal to an MMP of said MMPs; inputting the single mode optical signals to the SMPs; performing mode processing of one or more of the single mode and multi mode optical signals within the switching module, controllably and selectively switching different optical signals inputted to different ports of the module, preferably based on received feedback related to quality information, thereby allowing switching between single mode ports, between multi-mode ports, and between single mode and multi mode ports.

Abstract: A technique for monitoring at least a network portion of an optical communication network, by monitoring changes of a decision threshold used for discriminating a digital optical signal being propagated via the network portion.

Abstract: For determining OSNRreal of a real optical signal carried in an optical network link, the following has been proposed: tapping a portion of the real optical signal, altering the tapped signal portion by adding to it in-band artificial noise signal, thus obtaining a combined signal, scattering the combined signal by stimulated Brillouin or Raman scattering (SBS or SRS) in an optical element, extracting a signal back reflected by SBS/SRS from the optical element, determining OSNRcomb of the back reflected signal and deriving the OSNRreal from the OSNRcomb knowing absolute and/or relative power of the added artificial noise.

Abstract: A reconfigurable wavelength selective dispersion compensation device RWSDCD for selective compensation of dispersion in optical channels having different wavelengths. The RWSDCD comprises a controllable wavelength selective unit WSU having a plurality of local, wavelength related input/output (I/O) ports. The RWDSD also comprises a dispersion compensation cascade comprising at least one chain of successively connected dispersion compensation units DCUs, wherein one or more of the DCUs in the chain are respectively connectable to one or more of the local I/O ports. The RWSDCD outputs one or more of the incoming optical channels upon selectively compensating chromatic dispersion in them, by controllably passing these channels via one or more DCUs of the dispersion compensation cascade.

Abstract: A simple and effective all-optical system, producing a multilevel coded optical signal based on the M-ASK technology and by the minimized equipment. The novel all-optical modulation technique for optical M-ASK generation is based on nonlinear interaction between optical signals, say between N 2-ASK modulated pump signals having extinction ratio ER1 and a single 2-ASK modulated optical probe signal having extinction ratio ER2. According to the invention, a 4-ASK optical signal can be obtained using just a single binary modulated pump optical signal and a single binary modulated probe optical signal.

Abstract: Technology for detecting an optical data signal carried in a combined optical signal that comprises a carrier optical signal modulated by the optical data signal and also comprises ASE noise. The proposed optical data detector/receiver is provided with an SHG device adapted to generate a second harmonic optical signal of the carrier optical signal modulated by the data signal. In the signal, generated by the SHG, the ASE noise will be essentially reduced.

Abstract: A method is provided for routing optical data, which method comprises transmitting optical addressing data to a first network element having routing capabilities, assigning an appropriate optical link connecting the first network element with a second network element where the assignment is based on the optical addressing data, and transmitting the optical data via the assigned optical link.

Abstract: A method and system are provided for improving bandwidth efficiency in an optical network by dynamically utilizing unused bandwidth located around preliminarily allocated optical channels. The method comprising monitoring actual bandwidth of the preliminarily allocated optical channels incoming to a node of the optical network, reporting the monitoring results to the controller of that node and further to a network controller, receiving at that node recommendations generated by the network controller, adjusting bandwidth of one or more of the allocated optical channels thereby releasing spare bandwidth for inserting one or more additional optical channels thereat.

Abstract: A technique for monitoring at least a network portion of an optical communication network, by monitoring changes of a decision threshold used for discriminating a digital optical signal being propagated via the network portion.

Abstract: A monitor for monitoring OSNR of data being carried via an optical network link, the monitor obtains an optical signal from the link, comprises a loop of a non-linear optical medium capable of producing a back reflected signal to the optical signal and of looping the back reflected signal; and comprises a device for extracting a portion of the looped back reflected signal from said loop. The monitor further comprises a first photodetector for measuring power of the optical signal and a second photodetector for measuring power of the extracted portion of the looped signal. Finally, there is a processing unit for determining OSNR of the optical signal based at least on readings of the first and the second photodetectors.

Abstract: A technique for securing data transmission via an optical communication line comprising an optical fiber extending between a first network element and a second network element; the technique comprises conveying a first optical signal carrying data via the optical fiber from the first network element towards the second network element at a predetermined optical wavelength, and conveying a second optical signal at the same predetermined optical wavelength via the same fiber in the opposite direction to create within the optical fiber a combined optical signal such that combination of the first and second optical signals is adapted to hamper an unauthorized non-intrusive extraction of the first optical signal from the combined optical signal.

Abstract: For determining OSNRreal of a real optical signal carried in an optical network link, real the following has been proposed: tapping a portion of the real optical signal, altering the tapped signal portion by adding to it in-band artificial noise signal, thus obtaining a combined signal, scattering the combined signal by stimulated Brillouin or Raman scattering (SBS or SRS) in an optical element, extracting a signal back reflected by SBS/SRS from the optical element, determining OSNRcomb of the back reflected signal and deriving the OSNRreal from the OSNRcomb knowing absolute and/or relative power of the added artificial noise.

Abstract: A technique is proposed for performing add/drop operations in an OADM assembly serving an optical network and comprising an add unit and a drop unit. With respect to at least one optical channel assigned to an optical wavelength ?, the OADM assembly is capable of dropping the channel from the network via the drop unit as a first signal, and adding the channel to the network via the add unit as a second signal. According to the technique, the OADM assembly additionally comprises an authentication and control unit ACU for authenticating the at least one optical channel and controlling the OADM assembly. The ACU is authenticates the optical channel by comparing one or more components of the first signal with one or more components of the second signal serving as a reference, and based on the authentication result, makes decisions whether to allow or block the dropping and/or adding of the optical channel.

Abstract: A reconfigurable wavelength selective dispersion compensation device RWSDCD for selective compensation of dispersion in optical channels having different wavelengths. The RWSDCD comprises a controllable wavelength selective unit WSU having a plurality of local, wavelength related input/output (I/O) ports. The RWDSD also comprises a dispersion compensation cascade comprising at least one chain of successively connected dispersion compensation units DCUs, wherein one or more of the DCUs in the chain are respectively connectable to one or more of the local I/O ports. The RWSDCD outputs one or more of the incoming optical channels upon selectively compensating chromatic dispersion in them, by controllably passing these channels via one or more DCUs of the dispersion compensation cascade.

Abstract: Technology for detecting an optical data signal carried in a combined optical signal that comprises a carrier optical signal modulated by the optical data signal and also comprises ASE noise. The proposed optical data detector/receiver is provided with an SHG device adapted to generate a second harmonic optical signal of the carrier optical signal modulated by the data signal. In the signal, generated by the SHG, the ASE noise will be essentially reduced.

Abstract: A technique for carrying out protection of data traffic in a multi-channel multi-section optical communications network by simultaneously using Optical Multiplexed Section (OMS) protection and Optical Channel (OCH) protection; the technique comprises selection of a working optical signal in an OCH protected optical channel, in case of a fault in a section of the network, by relying on an indication associated with OMS switching functionality that is required to overcome the mentioned fault.

Abstract: A simple and effective all-optical system, producing a multilevel coded optical signal based on the M-ASK technology and by the minimized equipment. The novel all-optical modulation technique for optical M-ASK generation is based on nonlinear interaction between optical signals, say between N 2-ASK modulated pump signals having extinction ratio ER1 and a single 2-ASK modulated optical probe signal having extinction ratio ER2. According to the invention, a 4-ASK optical signal can be obtained using just a single binary modulated pump optical signal and a single binary modulated probe optical signal.

Abstract: A technique for securing data transmission via an optical communication line comprising an optical fiber extending between a first network element and a second network element; the technique comprises conveying a first optical signal carrying data via the optical fiber from the first network element towards the second network element at a predetermined optical wavelength, and conveying a second optical signal at the same predetermined optical wavelength via the same fiber in the opposite direction to create within the optical fiber a combined optical signal such that combination of the first and second optical signals is adapted to hamper an unauthorized non-intrusive extraction of the first optical signal from the combined optical signal.

Abstract: A technique is described for controlling and optical network composed of network elements (NEs), with the aid of a network controller (NC) being in communication with the network elements. The technique includes collecting, by the network controller NC, information on the NEs therefrom, and, whenever a change in the network is requested, simulating within the NC operation of the network with the requested change and based on the collected information. The NC makes a decision on acceptability of the requested change, and may then cause implementation of the requested change in the network.

Abstract: For securing from invasion a group of network nodes in a multi-channel optical communication network, providing wavelength selective optical amplifiers WSOA in optical fiber links incoming network nodes of the group, and providing a network controller NC for holding and updating control information about optical channels allowed in specific optical fiber links incoming specific network nodes of the group, and for supplying each of the WSOAs with suitable control information concerning the incoming optical fiber links associated therewith. At each specific WSOA, in response to the received control information, blocking any incoming wavelength except for wavelengths assigned to the optical channels allowed in that specific incoming optical fiber link.