公开(公告)号：DE2960261D1

公开(公告)日：1981-05-07

申请号：DE2960261

申请日：1979-04-25

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： DI VITA PIETRO

IPC: G02B6/28 ,  H04B10/213 ,  G02B5/14

Abstract: The coupler comprises one or more optical systems formed by or equivalent to a set of reflecting surfaces (4,5,6) whose sections are segments of ellipses having two by two a common focus (1A, 2A, 3A); each focus lies in the centre of the end face of an optical waveguide (1,2,3) able both to launch a light beam to be shared among other waveguides, and to collect either a light beam resulting from a sharing or more light beams to be combined.

公开(公告)号：CA1072790A

公开(公告)日：1980-03-04

申请号：CA282705

申请日：1977-07-14

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： DI VITA PIETRO

IPC: G02B6/14 ,  H04B10/2507 ,  G02B3/08 ,  G02B3/14 ,  G02B5/32

Abstract: An optical equalizer is provided which connects two segments of a multimode optical waveguide in such a manner that the path length of all rays passing through the guide can be equalized regardless of their guidance angle. The equalizer comprises two identical lenses, or equivalent structure, the lenses having a variable focal length which varies according to the distance r from the axis of the system according to the relation where s is the distance between each lens, and the adjacent waveguide segment, d is the separation of the lenses and ?M is the maximum guidance angle of the waveguide segments.

公开(公告)号：DE3865627D1

公开(公告)日：1991-11-21

申请号：DE3865627

申请日：1988-11-02

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： DI VITA PIETRO

IPC: G02B6/00 ,  C03B37/14 ,  C03B37/15 ,  G02B6/02 ,  C03B37/10 ,  G02B6/16

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

IPC: G02B6/24 ,  G01M11/00 ,  G01N21/84

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.

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

IPC: G01J1/00 ,  G01J1/02 ,  G01J1/42 ,  G01J4/00 ,  G01M11/00 ,  G01R29/08

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.

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

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

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.

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

IPC: G01J1/00 ,  G01J1/02 ,  G01J1/42 ,  G01J4/00 ,  G01M11/00 ,  G01B

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.

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

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

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.

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

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

公开(公告)号：CA1141188A

公开(公告)日：1983-02-15

申请号：CA363897

申请日：1980-11-03

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： DI VITA PIETRO

IPC: G01M11/02 ,  G01N21/41 ,  G01N21/01

Abstract: The determination of the refractive index profile of an optical fibre by the near-field technique is made possible for any kind of fibre by introducing the fibre into a transparent capillary tube, with refractive index lower than the minimum refractive index of the fibre and filled with a liquid with refractive index higher than the maximum refractive index of the fibre.