Abstract: Delivering multicast data traffic over a communication network includes a first network node delivering multicast data traffic to second network nodes. The first and second network nodes are connected by a transmission network in a ring architecture and implement a point-to-multipoint layer 2 protocol. A method includes at the first network node: collecting alarms signals indicative of a failure along the whole ring and of the second network nodes. Based on a current state of the alarm signals, delivering the multicast data traffic either in a first delivery direction along the ring, or in a second delivery direction along the ring opposite to the first delivery direction, or in both the first and second delivery directions. At each of the second network nodes: collecting alarm signals indicative of a failure of the transmission network locally to the second network node and of the second network node.

Abstract: Delivering multicast data traffic over a communication network includes a first network node delivering multicast data traffic to second network nodes. The first and second network nodes are connected by a transmission network in a ring architecture and implement a point-to-multipoint layer 2 protocol. A method includes at the first network node: collecting alarms signals indicative of a failure along the whole ring and of the second network nodes. Based on a current state of the alarm signals, delivering the multicast data traffic either in a first delivery direction along the ring, or in a second delivery direction along the ring opposite to the first delivery direction, or in both the first and second delivery directions. At each of the second network nodes: collecting alarm signals indicative of a failure of the transmission network locally to the second network node and of the second network node.

Abstract: The present invention relates to a new model for interpreting interferometric measurements, able to lead to a new method, system (10) and device (27) for measuring the PMD (Polarisation Mode Dispersion) of an optical fibre (11). The model, which is based on the theory of propagation of the optical signal as can be determined according to the socalled Prindpal States of Polarisation (PSPs) of the fibre, leads to a new interpretation of the interferogram generated with the interferometric measurements and is characterized in that it identifies in said interferogram a central peak and two side lobes. Thanks to this new model, it is possible to determine the PMD of the fibre based on the information content associated to at least one of the two side lobes identified in the interferogram.

Abstract: An apparatus and method for characterizing or measuring chromatic dispersion in an optical fiber segment. The fiber is accessed at one end with a signal generator injecting modulating pulsed signals which are reflected at the other end of the fiber, the apparatus determining the phase difference between the modulation signals and the reflected modulation signals and calculating the chromatic dispersion therefrom.

Abstract: The present invention relates to a new model for interpreting interferometric measurements, able to lead to a new method, system (10) and device (27) for measuring the PMD (Polarisation Mode Dispersion) of an optical fibre (11). The model, which is based on the theory of propagation of the optical signal as can be determined according to the socalled Prindpal States of Polarisation (PSPs) of the fibre, leads to a new interpretation of the interferognram generated with the interferometric measurements and is characterised in that it identifies in said interferogramn a central peak and two side lobes. Thanks to this new model, it is possible to determine the PMD of the fibre based on the information content associated to at least one of the two side lobes identified in the interferogram.

Abstract: The present invention relates to an apparatus and method for mitigating the effects of polarization mode dispersion (PMD) in high speed optical signal transmission systems. The apparatus comprises a concatenation of birefringent elements (11, 12, 16) of which at least two (11, 12) can be selectively controlled by means of a feedback device (15), and is capable of mitigating the effects of first- and second-order PMD even through the architecture used features a limited number of control connections (11a, 12a9 and corresponding control signals.

Abstract: The present invention relates to an apparatus (10) that allows to characterise or measure the chromatic dispersion in an optical fibre segment (50) by accessing a single end of the fibre itself (50) and measuring the phase shift between modulating signals of impulsive kind generated by a signal generator (12) and the same modulation signals reflected by a remote end of the fibre (51). The invention further relates to the method for measuring the chromatic dispersion of the optical fibre (50). Thanks to the invention, the apparatus (10) does not require an absolute external reference signal and allows to determine the chromatic dispersion of the fibre (50) being measured as the wavelength of the optical signals varies.

Abstract: The process and apparatus to enable measurement of polarization dispersion of a single-mode optical fibre by launching measurement light at one end of the fibre and analyzing polarization of the light reflected by the other end and collected at such launch end. Optical or electronic masking of light reflected by the near end of the fibre is performed during launch.