Abstract: An optical PON network comprises a central office which generates N DPSK modulated optical signals, where N is an integer greater than 1, an optical coupling which connects the N signals to at least one optical fibre, a passive distribution mode located remotely from the central office which has at least one input port that is coupled to the fibre and a plurality of output node being arranged to transmit a first wavelength of the N signals to at least one of its output ports, and at least one optical network unit connected through a respective optical fibre to the first output port of the passive distribution node. The passive distribution node comprises an arrayed waveguide grating which provides a passive optical connection between its input port and the first output port and which for that connection functions as a bandpass filter having a profile and bandwidth selected such that the DPSK optical signal passed to the input node is converted to an intensity modulated signal at the output port.

Abstract: A signal processor for compensating for optical fibre chromatic dispersion comprising encoding means (5) for encoding a source signal (2) received from a data source (6), splitting means (8) to separate the encoded signal (7) from the encoding means (5) into an in-phase component (10) and an in-quadrature component (11), a first filter means (12) adapted to receive the in-phase component (10) and a second filter means (13) adapted to receive the in-quadrature component (11), the first filter means (12) and second filter means (13) being adapted to filter the in-phase and in-quadrature components respectively. The outputs (14, 15) from the filter means form the input to the optical modulator means (3).

Abstract: A method of assessing the feasibility of a composite optical path in an optical communications network in which the composite path is composed of two optical paths k1 and k2 is described. The method comprising the steps of defining, for each individual optical path k and with type i interface, at least one parameter indicating its feasibility, calculating a quality Q factor Q?_i,k1+k2 of the signal for the composite path, estimated considering the deterioration which affects transmission over the paths k1 and k2 and comparing this quality Q?_i,k1+k2 with a value Qbare_i which is defined as the lowest value which can be taken on by a mapping function Q_i(.) for interface i and which gives the Q factor as a function of the OSNR received evaluated under the conditions that are considered to be the worst case that can be accepted while ensuring the desired signal quality.

Abstract: A method and apparatus for compensating for channel depletion of a multi-channel signal in an optical link or optical network comprising a chain of optical amplifiers. The method comprises determining channel depletion for each amplifier from the power of the input signal to the optical amplifier and the power of the output signal from the previous amplifier. Each amplifier is then controlled to amplify the signal to a level equal to the nominal (ideal) power plus the calculated channel depletion for that amplifier.

Abstract: A method of assessing the feasibility of a composite optical path in an optical communications network in which the composite path is composed of two optical paths k1 and k2 is described. The method comprising the steps of: defining, for each individual optical path k and with type i interface, at least one parameter indicating its feasibility, calculating a quality Q factor Q?_i,k1+k2 of the signal for the composite path, estimated considering the deterioration which affects transmission over the paths k1 and k2 and comparing this quality Q?_i,k1+k2 with a value Qbare_i which is defined as the lowest value which can be taken on by a mapping function Q_i(.) for interface i and which gives the Q factor as a function of the OSNR received evaluated under the conditions that are considered to be the worst case that can be accepted whilst ensuring the desired signal quality and wherein the composite connection is considered feasible if Q?_i,k1+k2>=Qbare_i.

Abstract: A method for optimisation of the number and location of regenerative or non-regenerative repeaters in a WDM link made up of N spans connected in a succession of N?1 intermediate sites to form link sections separated by sites containing regenerative repeaters, comprises a step for defining the number of regenerative repeaters needed and giving them a first location. Said step comprises the phases of defining targets OSNRs (VOSNRT) as a function of the number of spans and the type of fibre used in the spans, and defining a possible section between an initial site and a final site, appraising a metric function VM for said possible section obtained as a function of the difference between the OSNR (VOSNR) at the final end of the first span of said possible section and the corresponding target OSNR (VOSNRT) given by the number of spans in said possible section.

Abstract: An iterative method for power pre-emphasis of N optical channels in a Wavelength Division Multiplex (WDM) signal in an optical communication systems in accordance with which representative Xi characteristics are defined for the channels with among the characteristics there being included at least one characteristic that is a function of the Bit Error Rate (BER).

Abstract: Data transmitted on optical fiber over long distances is subject to the introduction of errors at the receiving end, caused by distortions and alterations of the original data. Raising the transmission power to increase the level of signals at the receiving end also increases errors due to non-linear characteristics of the fiber. The invention optimizes launch power by assessing error rates due to amplified spontaneous emissions and due to four wave mixing, so that signal to noise ratios due to these causes exceed threshold levels while enabling launch power to be maximized.

Abstract: Data transmitted on optical fiber over long distances is subject to the introduction of errors at the receiving end, caused by distortions and alterations of the original data. Raising the transmission power to increase the level of signals at the receiving end also increases errors due to non-linear characteristics of the fiber. The invention optimizes launch power by assessing error rates due to amplified spontaneous emissions and due to four wave mixing, so that signal to noise ratios due to these causes exceed threshold levels while enabling launch power to be maximized.

Abstract: The present invention refers to a centralized system and process for measuring, registering, reading and billing data referring to electric energy consumption of a plurality of consumers (14-17), which receive the electric energy through a plurality of respective consumer connecting cables (18-21), connected to a main electric energy inlet cable (12) which, in turn, is connected to the electric energy distributing network (11).