OTDR using an electro-absorption modulator for both pulse forming and pulse detection

    公开(公告)号:US11137317B2

    公开(公告)日:2021-10-05

    申请号:US15728974

    申请日:2017-10-10

    Inventor: Andreas Fricke

    Abstract: An optical time domain reflectometer for determining properties of an optical transmission fiber, the optical time domain reflectometer comprising an electro-absorption modulator comprising a waveguide and two electrodes, wherein the waveguide is arranged between the electrodes, a light source configured for emitting sampling light into the waveguide, wherein the waveguide is connected or to be connected between the fiber and the light source, and a control unit for controlling the operation of the light source and a modulation voltage between the electrodes. The electro-absorption modulator is capable of assuming an absorption state, wherein the electro-absorption modulator is further configured for receiving reflected light pulses resulting from the reflection of the pulses of sampling light in the fiber, wherein the absorption of reflected light pulses in the electro-absorption modulator results in the creation of a photocurrent between the electrodes.

    Detection of gainers and exaggerated losses in unidirectional OTDR traces

    公开(公告)号:US10753824B2

    公开(公告)日:2020-08-25

    申请号:US16341731

    申请日:2017-11-21

    Inventor: Lutz Rapp

    Abstract: A method of distinguishing whether a detected change in reflected power in an optical time domain reflectometer (OTDR) measurement carried out in a fiber optic transmission system (16) using an OTDR is caused by a an event causing actual attenuation or a change in a mode field diameter, comprising the steps of emitting a succession of first sampling light pulses of a first wavelength into the fiber optic transmission system (16) while a pumping signal with a second wavelength is emitted into the fiber optic transmission system (16), and measuring a first OTDR trace (34′) resulting from the reflection of the first sampling light pulses in the fiber optic transmission system (16), such that the first sampling light pulses and their reflections interact with the pumping signal via stimulated Raman scattering. The method further comprises a step (36) of determining, based at least on information extracted from the first OTDR trace (34′), whether the detected change is mainly due to an event causing actual attenuation or to a change in the mode field diameter in the fiber optic transmission system (16).

    Method and system for assigning resources in optical transport networks

    公开(公告)号:US10511402B2

    公开(公告)日:2019-12-17

    申请号:US16096215

    申请日:2017-11-21

    Abstract: The proposed invention is in the area of managing resources in optical transport networks, for example in the area of in-operation media channel format and spectrum management. For this purpose, the type of Media Channel Format is determined for each of a plurality of candidate paths, wherein each candidate path connects a pair of nodes in an optical transport network. Then, the expected weight describing traffic volume of each of the candidate paths is determined, and a spectrum share is assigned to each link of each of the candidate paths based on the determined Media Channel Formats and determined weights. In this way, spectrum shares assigned to different links and candidate paths can be used for efficiently assigning a band spectrum to each of the Media Channel Formats of the candidate paths.

    Encoder, decoder and encoding method with low error floor

    公开(公告)号:US10256841B2

    公开(公告)日:2019-04-09

    申请号:US15533912

    申请日:2015-12-18

    Abstract: An encoder encodes digital data, said encoder includes one or more component encoders, one or more interconnections between component encoders, one or more inputs and one or more outputs. The encoder is configured to carry out the following steps: combining internal input bits received via an interconnection and external input bits received via a corresponding input, to assemble a local information word, encoding the local information word such as to generate a local code word, outputting a reduced local code word and handling the same reduced local code word over to the interconnect for forwarding the same reduced local code word to another component encoder or to itself, wherein the encoder is configured to forward on each interconnect the bits of the reduced local code in parallel but with delays that are mutually different for at least a subset of the reduced local code word bits.

    RAMAN PUMPING ARRANGEMENT WITH IMPROVED OSC SENSITIVITY

    公开(公告)号:US20180083413A1

    公开(公告)日:2018-03-22

    申请号:US15661756

    申请日:2017-07-27

    Inventor: Lutz RAPP

    Abstract: A Raman pumping arrangement for amplifying a data optical signal (40) has a Raman pump (12) for generating a Raman pump signal (44;45), an optical supervisory channel receiver (14) for receiving an optical supervisory channel signal (42) an amplification fiber (15) arranged such that the data optical signal (40), the optical supervisory channel signal (42), and the Raman pump signal (44;45) are transmitted therethrough; and a control unit (13) configured for controlling the operation of the Raman pump (12); wherein the control unit (13) is configured for setting the Raman pump (12) in an operation mode or a start-up mode; wherein in the operation mode, the Raman pump (12) provides an operation pumping power (120), and wherein in the start-up mode, the Raman pump (12) provides a start-up pumping power (122).

    Dual parallel Mach-Zehnder-modulator device with pre-distorted driving voltages

    公开(公告)号:US11296796B2

    公开(公告)日:2022-04-05

    申请号:US16286147

    申请日:2019-02-26

    Abstract: Disclosed herein is a dual parallel Mach-Zehnder-modulator (DPMZM) device comprising a DPMZM 10 having first and second inner MZMs arranged parallel to each other. The first inner MZM generates an in-phase component EI of an optical signal in response to a first driving voltage VI, and the second inner MZM generates a quadrature component EQ of said optical signal in response to a second driving voltage VQ. Further disclosed is a calculation unit 52 configured for receiving an in-phase component yI and a quadrature component yQ of a desired base-band signal, and for calculating pre-distorted first and second driving voltages VI, VQ. The calculation of the pre-distorted first and second driving voltages VI, VQ is based on a model of said DPMZM 10 accounting for I-Q cross-talk, and using an algorithm that determines said first and second driving voltages VI, VQ each as a function of both of said in-phase and quadrature components yI, yQ of said base-band signal.

    OTDR with increased precision and reduced dead zone using superposition of pulses with varying clock signal delay

    公开(公告)号:US11287352B2

    公开(公告)日:2022-03-29

    申请号:US16093038

    申请日:2017-05-24

    Abstract: A method for determining the position of an irregularity in an optical transmission fiber using an optical time domain reflectometer, the method comprising the steps of emitting a succession of sampling light pulses into the optical transmission fiber, detecting reflected light pulses resulting from the reflection of the sampling light pulses at the irregularity in the optical transmission fiber and generating corresponding time-dependent detection signals, wherein different delays are associated with detection signals corresponding to different sampling light pulses, obtaining a combined signal from the detection signals, and analyzing the combined signal for determining the position of the irregularity in the optical transmission fiber with respect to the optical time domain reflectometer, wherein the combined signal corresponds to a superposition of the detection signals.

    Performance monitoring for a transmission system with forward error correction

    公开(公告)号:US11190306B2

    公开(公告)日:2021-11-30

    申请号:US16723462

    申请日:2019-12-20

    Inventor: Stefano Calabró

    Abstract: A system for determining a channel margin of a data transmission channel (DTC) using error correction under real-world channel conditions is described. The system includes a monitoring unit, an operating state determining unit and a data processing unit. The monitoring unit monitors data transmission along the DTC and estimates a statistical distribution of errors (H) in the transmission of data. The operating state determining unit determines a current value of an operating state parameter for the DTC. The data processing unit determines a reference channel margin associated with said current value of the operating state parameter for a reference channel and the error correction scheme employed, provides a statistical distribution of errors (HR) associated with said reference channel for said current value of said operating state parameter, compute a deviation of H and HR, and computes a reduction of the reference channel margin.

    METHOD AND SYSTEM FOR MANAGEMENT OF A LOCAL CRAFT TERMINAL APPLICATION EXECUTED BY A NETWORK ELEMENT

    公开(公告)号:US20210200557A1

    公开(公告)日:2021-07-01

    申请号:US16730219

    申请日:2019-12-30

    Abstract: A method and system for managing execution of a local craft terminal application on a local computer system comprising accessing one of the plurality of remote network elements and obtaining therefrom a launcher application program configured to manage execution of the local craft terminal application on the local computer system, launching the launcher application program on the local computer system and determining, using the launcher application program, whether the local computer system contains an appropriate copy of the local craft terminal application, and if the local computer system does not contain the appropriate copy of the local craft terminal application, obtaining the appropriate copy of the local craft terminal application from the first one of the plurality of remote network elements.

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