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    METHOD OF AND DEVICE FOR REAL TIME MEASUREMENT OF THE STATE OF POLARIZATION OF A QUASI-MONOCHROMATIC LIGHT BEAM
    2.
    发明专利
    METHOD OF AND DEVICE FOR REAL TIME MEASUREMENT OF THE STATE OF POLARIZATION OF A QUASI-MONOCHROMATIC LIGHT BEAM 未知

    公开(公告)号：CA1240174A

    公开(公告)日：1988-08-09

    申请号：CA485943

    申请日：1985-06-28

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： CALVANI RICCARDO ,  CISTERNINO FRANCESCO ,  CAPONI RENATO

    IPC: G01J4/04 ,  G01J4/00 ,  G01J9/04 ,  G01N21/21

    Abstract: An interference technique is used to measure the state of polarization of a quasi-monochromatic light beam. Two quasi-monochromatic radiations with slightly different optical frequencies are generated. One radiation is converted into a 45.degree. linearly polarized radiation, whilst the other presents the polarization state imposed by a body under test. In each radiation, horizontal and vertical polarization components are separated, and the horizontal and vertical components are then respectively recombined into two different beams each comprising radiations at both frequencies, polarized in the same plane. Beats between the two components in each beam are generated and used to generate two electrical signals in the radio frequency range, from which information is extracted as to the relative phase and the amplitude of the two components of that radiation whose polarization is imposed by the body under test.

    3.
    发明专利
    未知

    公开(公告)号：IT1303598B1

    公开(公告)日：2000-11-14

    申请号：ITTO981032

    申请日：1998-12-10

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： CALVANI RICCARDO ,  CISTERNINO FRANCESCO ,  RICCARDI EMILIO ,  GIRADI RAFFAELE

    IPC: G02F1/35 ,  H04J3/00 ,  H04J14/08

    Abstract: This invention concerns a method of and a device for optical demultiplexing that are based on the four wave mixing between the signals to be demultiplexed and pump signals. The two signals are fed into a polarisation maintaining fibre (14), which divides them into two components with orthogonal polarisation, separated in time; and the four wave mixing is performed separately on the two components, thereby originating two separate signals that are polarisation-rotated and re-combined.

    4.
    发明专利
    未知

    公开(公告)号：IT1266016B1

    公开(公告)日：1996-12-16

    申请号：ITTO940443

    申请日：1994-05-30

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： ARTIGLIA MASSIMO ,  CAPONI RENATO ,  CISTERNINO FRANCESCO ,  NADDEO CLAUDIO ,  ROCCATO DIEGO

    IPC: G01M11/02 ,  G01M11/00

    Abstract: To measure the nonlinear refractive index of an optical fibre, each pulse emitted by a source (L) is split into a pair of pulses which are sent in opposite directions into an optical-fibre Sagnac interferometric loop (AS) which includes the fibre under test (F). One of the pulses of the pair is attenuated before passing through the fibre (F) in such a way that only the other one has such a power as to induce nonlinear effects in the fibre (F). The interference between parts of pulses is analysed at the output of the loop (AS) and the nonlinear refractive index is derived from a measurement of the phase shift between the two pulses of the pair.

    5.
    发明专利
    未知

    公开(公告)号：ITTO940443D0

    公开(公告)日：1994-05-30

    申请号：ITTO940443

    申请日：1994-05-30

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： ARTIGLIA MASSIMO ,  CAPONI RENATO ,  CISTERNINO FRANCESCO ,  NADDEO CLAUDIO ,  ROCCATO DIEGO

    IPC: G01M11/02 ,  G01M11/00 ,  G01N2

    Abstract: To measure the nonlinear refractive index of an optical fibre, each pulse emitted by a source (L) is split into a pair of pulses which are sent in opposite directions into an optical-fibre Sagnac interferometric loop (AS) which includes the fibre under test (F). One of the pulses of the pair is attenuated before passing through the fibre (F) in such a way that only the other one has such a power as to induce nonlinear effects in the fibre (F). The interference between parts of pulses is analysed at the output of the loop (AS) and the nonlinear refractive index is derived from a measurement of the phase shift between the two pulses of the pair.

    OPTO-ELECTRONIC FREQUENCY DIVIDER CIRCUIT AND METHOD OF OPERATING SAME
    7.
    发明专利
    OPTO-ELECTRONIC FREQUENCY DIVIDER CIRCUIT AND METHOD OF OPERATING SAME 未知

    公开(公告)号：CA2256188A1

    公开(公告)日：1999-06-16

    申请号：CA2256188

    申请日：1998-12-15

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： ROEMISCH STEFANIA ,  GIRARDI RAFFAELE ,  CISTERNINO FRANCESCO ,  DE MARCHI ANDREA

    IPC: G02F1/03 ,  H04B10/155 ,  H04J14/08 ,  H04L7/00 ,  G02F2/02 ,  H04J14/02

    Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator, with non-linear behaviour. The modulator receives as input an optical signal at the frequency to be divided, in addition to an electric signal at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal from modulator exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal, the output signal of the mixer is subjected to a filtering action to extract the above frequency difference component. This latter one is then used both as electrical signal for the mixing, and as output signal from the divider. The preferred application is to OTDM systems, to extract a synchronism signal at tributary signal frequency.

    METHOD OF MEASURING POLARIZATION AND BIREFRINGENCE IN SINGLE MODE OPTICAL FIBRES
    9.
    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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