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    2.
    发明专利
    未知

    公开(公告)号：DE3864743D1

    公开(公告)日：1991-10-17

    申请号：DE3864743

    申请日：1988-05-18

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： CALVANI RICCARDO ,  CAPONI RENATO ,  CISTERNINO FRANCESCO ,  COPPA GIANNI

    IPC: G01M11/00 ,  G01M11/02 ,  G01N21/23 ,  G02B6/00

    Abstract: A constant force perpendicular to the fibre axis is applied to the fibre (2) so as to cause a power coupling from the fundamental mode, which is guided, to a secondary mode which is irradiated, and the intensity of the scattered radiation associated with that secondary mode is measured. Such intensity depends on the local state of polarization. By displacing the force application point step by step along the fibre axis and by measuring for each point the intensity of the scattered radiation, beat length is obtained as the distance between two consecutive points where the scattered radiation has the same intensity.

    3.
    发明专利
    未知

    公开(公告)号：IT1180071B

    公开(公告)日：1987-09-23

    申请号：IT6758084

    申请日：1984-06-05

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： COPPA GIANNI ,  DI VITA PIETRO

    IPC: G01M11/00 ,  G01M11/02 ,  G01M11/08 ,  H01P

    Abstract: The process is based on the fact that the introduction of perturbations in an optical fibre can generate greater losses on higher order modes. Therefore, a spectral scanning of the fibre output power is effected under a certain number of different perturbation conditions and the values obtained are combined so as to determine the fraction of power guided in the fundamental mode. The cut-off wavelength is that where this fraction exceeds a certain value. The equipment implementing the process is also provided.

    4.
    发明专利
    未知

    公开(公告)号：IT1171039B

    公开(公告)日：1987-06-10

    申请号：IT6817183

    申请日：1983-11-10

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： COPPA GIANNI ,  DI VITA PIETRO ,  ROSSI UMBERTO

    IPC: G01J1/02 ,  G01J1/42 ,  G01J9/00 ,  G01M11/00 ,  G01R29/08 ,  G01R

    Abstract: The value of a transverse moment of any order of the electromagnetic field associated with an optical beam (and in particular the spot-size of such a beam) is determined by two successive measurements of the optical power of the beam: one measurement is a direct measurement, the other is effected after spatially modulating the transverse distribution of the electromagnetic field by a factor proportional to the n-th power of the transverse coordinate of the beam, n being the moment order. The moment can be obtained from the ratio between the two measurements. The invention includes also the apparatus for carrying out the method.

    METHOD OF MEASURING POLARIZATION AND BIREFRINGENCE IN SINGLE MODE OPTICAL FIBRES
    7.
    发明专利
    METHOD OF MEASURING POLARIZATION AND BIREFRINGENCE IN SINGLE MODE OPTICAL FIBRES 未知

    公开(公告)号：CA1313055C

    公开(公告)日：1993-01-26

    申请号：CA567120

    申请日：1988-05-18

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： CALVANI RICCARDO ,  CAPONI RENATO ,  CISTERNINO FRANCESCO ,  COPPA GIANNI

    IPC: G01M11/00 ,  G01M11/02 ,  G01N21/23 ,  G02B6/00

    Abstract: In a method of measuring the local polarization state within a fibre, or measuring the beat length characterizing the birefringence of an optical fibre, a constant force is applied to the fibre, perpendicular to its axis, to cause a coupling of energy from the fundamental radiation propagation mode of the fibre into a secondary mode which is radiated. The intensity of the scattered radiation associated with the secondary mode is then measured. This intensity is a function of the local state of polarization of radiation in the fibre. By displacing the point at which the force is applied stepwise along the axis of the fibre and by measuring at each point the intensity of the scattered radiation, the beat length is obtained as the distance between two consecutive points at which the scattered radiation has the same intensity.

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