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公开(公告)号：IT1182686B
公开(公告)日：1987-10-05
申请号：IT6796685
申请日：1985-11-15
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： CAPONI RENATO , COPPA GIANNI , DI VITA PIETRO
Abstract: The method of measuring mode field radius in single-mode optical fibres comprises the modulation of an optical beam by means of a spatial filter with radial-distribution of transmittivity of Gaussian type. Modulated beam intensity is measured in correspondence with the beam axis for different widths of the Gaussian curve, and the mode field radius is derived from both such intensity values and a parameter dependant on the Gaussian width. The apparatus which implements the method is also provided.
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12.发明专利
公开(公告)号：CA1203702A
公开(公告)日：1986-04-29
申请号：CA442465
申请日：1983-12-02
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO
Abstract: A method of measuring the cut-off wavelength of the first higher order mode in optical fibres, in which linearly polarized light is launched into one end of a fibre sample, the light being at successively different wavelengths and the light leaving the fibre being passed through an analyzer crossed with the polarization axis of the light input. The cut-off wavelength is that at which the output signal from the analyzer becomes zero.
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13.发明专利
公开(公告)号：CA1195858A
公开(公告)日：1985-10-29
申请号：CA419994
申请日：1983-01-21
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , GREGO GIORGIO
Abstract: A method of measuring the thickness and refractive index of a transparent material is based on phase difference measurements. A Zeeman effect laser generates a light beam containing two radiation components with slightly different frequencies which produce a first beat with one another at the end of an optical path external to the material. The beam is also split into its two radiation components and two further beats are generated between a first radiation component, which is made to follow a path outside the material, and second radiation components obtained by making the second component follow two different paths within the material. The phase differences between these further beats with respect to the first beat are measured by a phase-comparison system, and refractive index values as well as the thickness values can be computed.
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公开(公告)号：CA1264960A
公开(公告)日：1990-01-30
申请号：CA507721
申请日：1986-04-28
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： CALZAVARA MASSIMO , COPPA GIANNI , DI VITA PIETRO
Abstract: A method and apparatus are provided for measuring optical coupling losses between single-mode optical fibres, wherein an optical beam is injected into a length of optical fibre, the optical beam exiting from a fibre end face being reflected by a reflecting optical system back into said fibre through said face, and reemerging its injection point, and wherein the optical power of the reflected beam is measured, under a reference condition in which the core portion of the end face and its image produced by the optical beam reflected by the reflecting optical system coincide at the optical centre of the reflecting optical system, as well as under conditions of transverse or longitudinal offset from the reference condition. Various types of reflecting optical systems and arrangements for aligning the apparatus prior to a measurement are described.
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公开(公告)号：CA1260065A
公开(公告)日：1989-09-26
申请号：CA497157
申请日：1985-12-09
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO
Abstract: A method and an apparatus are provided for measuring the transverse moments of the electromagnetic field associated with an optical beam, wherein the beam is caused to pass through a slit, perpendicular to the beam propagation direction, a scanning of the beam is effected relative to the slit to generate a relative oscillatory motion between the beam and the slit in a direction perpendicular to the slit and to the propagation direction of the beam, a periodic electrical signal is generated consisting of pulses at a frequency half the frequency of the oscillatory motion, and whose amplitude and shape is dependent on the intensity distribution of the beam fraction which has passed through the slit, the periodic signal is resolved into its spectral components,the amplitude values of such components are measured, and the moment values are derived from the amplitude values so measured.
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Patent Agency Ranking
公开(公告)号：DE3477265D1
公开(公告)日：1989-04-20
申请号：DE3477265
申请日：1984-11-07
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO , ROSSI UMBERTO
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.
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17.发明专利
公开(公告)号：DE3374216D1
公开(公告)日：1987-12-03
申请号：DE3374216
申请日：1983-02-07
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , GREGO GIORGIO
Abstract: The invention is based on phase difference measurements. A Zeeman effect laser (3) generates a light beam (4) containing two radiations with slightly different frequencies whose beat is generated at the end of a path external to the material (1, 2a, 101). The same beam is split into the two component radiations (4c, 4d); the beats are generated between the first radiation, which is made to follow a path outside the material, and two radiations obtained by making the second radiation follow two different paths inside the material. The phase differences of these two beats with respect to the first are measured by a phase-comparison system (20, 21), and the refractive-index values as well as the thickness values are obtained by suitable computing means.
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公开(公告)号：IT1179854B
公开(公告)日：1987-09-16
申请号：IT6822484
申请日：1984-12-10
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO
Abstract: A method and an apparatus are provided wherein a light beam is passed through a slit (7) oscillating with respect to the beam, and a periodic signal is obtained from the beam portion traversing the slit and is split into its spectral components. Moment values are derived from the values of the amplitudes of such components.
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19.发明专利
公开(公告)号：CA1225843A
公开(公告)日：1987-08-25
申请号：CA480517
申请日：1985-05-01
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO
Abstract: A process for measuring the cut-off wavelength of higher order propagation modes in optical fibres is based on the fact that the introduction of perturbations in the transmission characteristics of an optical fibre can generate greater losses in higher order modes. A spectral scanning of the fibre output power is effected under a number of different perturbation conditions and the values obtained are combined so as to determine the fraction of power propagated in the fundamental mode. The cut-off wavelength is defined as that where this fraction exceeds a certain value.
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20.发明专利
公开(公告)号：DE3365484D1
公开(公告)日：1986-09-25
申请号：DE3365484
申请日：1983-12-12
Applicant: CSELT CENTRO STUDI LAB TELECOM
Inventor： COPPA GIANNI , DI VITA PIETRO
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