公开(公告)号：IT8467580D0

公开(公告)日：1984-06-05

申请号：IT6758084

申请日：1984-06-05

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： VITA GIANNI COPPA PIETRO DI

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.

公开(公告)号：IT8267735D0

公开(公告)日：1982-06-09

申请号：IT6773582

申请日：1982-06-09

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： VITA GIANNI COPPA PIETRO DI ,  POTENZA MARCELLO ,  ROSSI UMBERTO

IPC: G01M11/02 ,  G01N21/41 ,  G02B6/00 ,  G01N

公开(公告)号：IT8368171D0

公开(公告)日：1983-11-10

申请号：IT6817183

申请日：1983-11-10

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： VITA GIANNI COPPA PIETRO DI ,  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.