Abstract: An add-drop multiplexer has a group filter that divides an incoming WDM signal into several channel groups of corresponding adjacent WDM channels. A reconfiguration module is connected to each channel group. A first type of module makes it possible to perform a manual configuration of the Add-Drop channels and the coupled WDM channel while a second type of module makes it possible to carry out remote configuration. A fourth type of module enables remote configuration of the drop-continue channels.

Abstract: A tunable add/drop&continue or drop&continue module comprises two optical filters where at least one is tunable and that are arranged following one another between a branching unit for optical signals and an insertion unit follow a branching unit for optical signals. The reflection attenuation of the one tunable optical filter is lower and the transmission attenuation higher than that of the other optical filter, as a result of which the drop&continue function of the module can be realized without high circuit-oriented expense.

Abstract: The present invention relates to a network node that includes optical add/drop modules such that a module can be exchanged without disruption of the connections.

Abstract: An optical filter, adjustable add-drop-continue module and circuit for bundled cross-connect functionality, wherein the transmission response of the optical filter is varied by changing its temperature, tuning of the filter can be carried out by mechanical pressure or tension, the filter can be used to produce add-drop-continue modules which are suitable both for add-drop operation and for drop-continue operation, and cross-connect modules can be constructed from the optical filters.

Abstract: A pumping source for Raman amplification of an optical wavelength-division multiplex signal which has a number of pump lasers with different pumping wavelengths in each case. The pumping wavelengths are selected in such a way that mixing products from a four-wave mixing are minimized in or removed from the signal spectrum. Transmission bands for the channels of the WDM signal also can be defined in the signal spectrum such that the mixing products are situated between the transmission bands. Differences in the signal-to-noise ratios between the channels of the WDM signal on the basis of four-wave mixing are, therefore, efficiently minimized in the signal spectrum.

Abstract: A method and system for regulating the decision threshold and the sampling clock phase of a data regenerator for a binary signal, wherein error correction signals for erroneous 1-bits and 0-bits are used for regulating the decision threshold of a decision stage, and further phase correction signals between transitions of binary signals serve for the phase regulation of a sampling clock signal.

Abstract: An optical network node is provided having add-drop and/or cross-connect functions, wherein the optical network node includes a first optical line with a first drop branch and a first add branch, and a second optical line with a second drop branch and a second add branch, wherein the first drop branch and the second drop branch are in each case connected to a first cross-connect and to a second cross-connect, the first add branch is connected to the first cross-connect and to the second cross-connect via a first wavelength converter, and the second add branch is connected to the first cross-connect and to the second cross-connect via a second wavelength converter.

Abstract: A method and arrangement for the determination and separation of single channel effects “Group Velocity Dispersion” (GVD), “Self Phase Modulation” (SPM), “Intra Channel Cross-talk” (ICC) and “Stimulated Brillouin Scattering” (SBS) on optical transmission of a wavelength multiplex (WDM) signal which comprises several channels are disclosed. The channels are separated by a demultiplexer and fed to an electrooptical converter for the generation of electrical signals. The electrical signals comprising broadband frequency data contain distortions due to the single channel effects on optical transmission. The electrical signals are supplied to an electrical spectrum analyser and an electrical amplitude distributor for the analysis, determination and separation of the single channel effects.

Abstract: A method for determining interactions between a number of optical channels in a wavelength division multiplexed signal wherein, given that during broadband optical transmission, the quality of a “Dense Wavelength Division Multiplexed” signal is adversely affected by multiple channel interactions, the method is used to determine the governing effects, the Kerr effect and the non-linear scattering process by evaluating the spectral profile of the Q factor or of the bit error rate.

Abstract: An optical network node is provided having add-drop and/or cross-connect functions, wherein the optical network node includes a first optical line with a first drop branch and a first add branch, and a second optical line with a second drop branch and a second add branch, wherein the first drop branch and the second drop branch are in each case connected to a first cross-connect and to a second cross-connect, the first add branch is connected to the first cross-connect and to the second cross-connect via a first wavelength converter, and the second add branch is connected to the first cross-connect and to the second cross-connect via a second wavelength converter.

Abstract: Several wavelength multiplexers (WM1, WM2) to which optical signals (KS11-KS1n; KS21-KS2n) are supplied are interconnected by an optical coupler. Said optical signals (KS11-KS1n; KS21-KS2n) are interleaved in order to form wavelength-multiplex signal (WMS). The wavelength multiplexers (WM1, WM2) have double channel bandwidths in relation to a multiplexer used to produce the wavelength multiplex signal (WMS) in a single stage so that the quality of the optical signals (KS11-KS1n; KS21-KS2n) is not reduced through the limitation of their spectra.

Abstract: A method and system for regulating the decision threshold and the sampling clock phase of a data regenerator for a binary signal, wherein error correction signals for erroneous 1-bits and 0-bits are used for regulating the decision threshold of a decision stage, and further phase correction signals between transitions of binary signals serve for the phase regulation of a sampling clock signal.

Abstract: A method for determining interactions between a number of optical channels in a wavelength division multiplexed signal wherein, given that during broadband optical transmission, the quality of a “Dense Wavelength Division Multiplexed” signal is adversely affected by multiple channel interactions, the method is used to determine the governing effects, the Kerr effect and the nonlinear scattering process by evaluating the spectral profile of the Q factor or of the bit error rate.

Abstract: A pumping source for Raman amplification of an optical wavelength-division multiplex signal which has a number of pump lasers with different pumping wavelengths in each case. The pumping wavelengths are selected in such a way that mixing products from a four-wave mixing are minimized in or removed from the signal spectrum. Transmission bands for the channels of the WDM signal also can be defined in the signal spectrum such that the mixing products are situated between the transmission bands. Differences in the signal-to-noise ratios between the channels of the WDM signal on the basis of four-wave mixing are, therefore, efficiently minimized in the signal spectrum.

Abstract: In an optical plug-type connection between two optical conductors having an optical terminal which receives an optical plug-type member, an electrical connection is provided for verifying that the optical plug-type connection has been made and/or released. This verification reduces the likelihood of an optical plug-type connection being erroneously acquired in the network management system and, thus, significantly reduces problems in locating errors in the optical communication system.

Abstract: Connected into a wavelength division multiplex ring network is a filter arrangement which has a low attenuation only for the individual useful signals of the wavelength division multiplex signal and recombines these, along with launched signals to form a wavelength division multiplex signal.

Abstract: The invention relates to an electro-optically switchable columnar liquid-crystalline system wherein the columns have ferroelectric transverse polarization.The molecules in the columns of electro-optically switchable ferroelectric phases are tilted to or otherwise aligned with the longitudinal axis of the columns in such a manner than the columns are ferroelectrically polarized. The ferroelectric polarization is in a direction transverse to the column axis or has at least one transverse component. The polarization direction need not be the same for all columns of a columnar phase. The transverse polarization of the columns is fully or partially realigned by application of an electrical field to the liquid crystal.The liquid-crystalline system according to the invention can be used to produce electro-optical switching and display devices.

Abstract: A process for preparing hypericin comprises oxidative dimerization of emodin anthrone and conversion of the intermediate protohypericin to hypericin by irradiation with visible light.

Abstract: A method of operating a particle-treating apparatus having a hollow foraminous drum centered on and rotatable about an upright axis comprises the steps of feeding particles into the upper portion of the interior of the drum, rotating the drum about the axis at a speed sufficient to form the particles into an annular body lying on the inner surface of the drum, passing a drying gas radially inward through the drum into the interior thereof and withdrawing the gas axially from the interior to at least partially fluidize the body and dry the particles, and collecting the particles beneath the drum as the body moves off the lower edge thereof. The rate of gas flow through the drum and the rotation rate of the drum are such that the body moves axially down in the interior toward the lower edge of the drum.

Abstract: Particles to be dried are loaded into the bottom of an upwardly open vessel which is then spun about a central axis at a speed sufficient to form the particles into an annular body and to urge the particles radially outwardly with a centrifugal force greater than the force of gravity. The outer wall of the vessel is gas-pervious and drying gas is passed radially inwardly through this wall to contact the particles and at least partially fluidize the body of particles. The dried particles are drawn off out of the upper end of the rotating vessel as fresh wet particles are loaded into the lower end.