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公开(公告)号：BR9404948A
公开(公告)日：1995-10-31
申请号：BR9404948
申请日：1994-12-12
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: Simple methods for magneto-optical current measurement and magneto-optical ammeters are specified, which are independent of temperature influences on the measurement result and require no compensation device for the light intensities of the light sources (LD1, LD2) used. Light beams (1, 2) from the two laser light sources (LD1, LD2) are alternately polarised orthogonally to each other by means of a beam splitter (3) and transmitted, via collimators (4, 6) which are connected via a polarisation-maintaining high-birefringence HB fibre (5), through a magneto-optical current sensor (7), an analyser (10), 2 collimators (11, 12) and multimode fibres (13) and (14) to photodetectors (DA, DB). 1st and 2nd light-power signals SA1, SB1, respectively, and 3rd and 4th light-power signals SA2, SB2, respectively, are derived one after the other from the photodetectors (DA, DB). Using a function generator (22) of a control and evaluation device (15), a current density I detected by the magneto-optical current sensor (7) is calculated according to: I = [SA1 . SB2/(SA2 . SB1) - 1]/(8 . V), V being the magneto-optical Verdet constant. It is possible to work with frequency-division multiplexing instead of time-division multiplexing. A low-birefringence LB fibre can be used instead of a solid-optical current sensor (7), light being propagated in both directions and evaluated separately.
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公开(公告)号：CZ9403235A3
公开(公告)日：1995-12-13
申请号：CZ323594
申请日：1994-12-19
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
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公开(公告)号：CZ323594A3
公开(公告)日：1995-12-13
申请号：CZ323594
申请日：1994-12-19
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: In order to make evaluation of polarisation-modulated light signals independent of temperature, direct and alternating parts of light-power signals (S1, S2) are evaluated separately. The algorithm required for this is specified.
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公开(公告)号：DE4344856A1
公开(公告)日：1995-07-06
申请号：DE4344856
申请日：1993-12-29
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
IPC: G01C19/72 , G01D5/34 , G01D5/353 , G01N21/21 , G01N21/41 , G01R15/24 , G01N21/59 , G01J4/00 , G02B6/00
Abstract: Fibre-optic sensors are used in reflection or transmission mode in almost all fields of measuring technology, among others, for monitoring industrial plants, in medical diagnostics and in aerospace. In these applications, the effects of mechanical, electrical, magnetic, acoustic, thermal and chemical signals are analysed. To provide for simpler signal analysis, laser light is coupled from a light source (1) into an optical feed line fibre (2) parallel to one of its two major axes. In a first splice (3), the light is introduced into a first optical reference fibre (4), the major axes of which are rotated by 45 DEG compared with those of the optical feed line fibre (2). In a second splice (5), the light passes into a second optical reference fibre (6) which has the same length as the first optical reference fibre (4) and which is rotated by 90 DEG with its major axes with respect to the first optical reference fibre (4). At a third splice (7), the light is coupled into an optical fibre (8) with low birefringence, which first forms a lambda /4 optical fibre loop (9) and then an optical sensor (10). The phase shift of the light can be statically or dynamically influenced by means of a phase modulator (M) in conjunction with the first optical reference fibre (4).
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公开(公告)号：DE4342410A1
公开(公告)日：1995-06-14
申请号：DE4342410
申请日：1993-12-13
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: Simple methods for magneto-optical current measurement and magneto-optical ammeters are specified, which are independent of temperature influences on the measurement result and require no compensation device for the light intensities of the light sources (LD1, LD2) used. Light beams (1, 2) from the two laser light sources (LD1, LD2) are alternately polarised orthogonally to each other by means of a beam splitter (3) and transmitted, via collimators (4, 6) which are connected via a polarisation-maintaining high-birefringence HB fibre (5), through a magneto-optical current sensor (7), an analyser (10), 2 collimators (11, 12) and multimode fibres (13) and (14) to photodetectors (DA, DB). 1st and 2nd light-power signals SA1, SB1, respectively, and 3rd and 4th light-power signals SA2, SB2, respectively, are derived one after the other from the photodetectors (DA, DB). Using a function generator (22) of a control and evaluation device (15), a current density I detected by the magneto-optical current sensor (7) is calculated according to: I = [SA1 . SB2/(SA2 . SB1) - 1]/(8 . V), V being the magneto-optical Verdet constant. It is possible to work with frequency-division multiplexing instead of time-division multiplexing. A low-birefringence LB fibre can be used instead of a solid-optical current sensor (7), light being propagated in both directions and evaluated separately.
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Patent Agency Ranking
公开(公告)号：DE59403756D1
公开(公告)日：1997-09-25
申请号：DE59403756
申请日：1994-02-02
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: The sensor head (1) is provided for a fibre-optic current measuring device. It has a twisted, low-birefringent (double-refracting) LB-fibre (14) which is guided around a current conductor (2) and serves to guide polarised light. With the LB-fibre (14) the Faraday rotation of the polarised light caused by the magnetic field (H) of the current (J) to be measured is detected. The LB-fibre (14) is spliced at its two ends in each case to one of two polarisation-maintaining, light-guiding HB-fibres (6, 7), one (6) of which feeds the polarised light. The two HB-fibres (6, 7) are in each case mounted next to the two splicing points (19, 20) while absorbing the torsional force caused by twisting the LB-fibre (14). The sensor head (1) is characterised by high measuring accuracy despite having a simple and robust construction.
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公开(公告)号：DE4344855A1
公开(公告)日：1995-07-06
申请号：DE4344855
申请日：1993-12-29
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: In order to make evaluation of polarisation-modulated light signals independent of temperature, direct and alternating parts of light-power signals (S1, S2) are evaluated separately. The algorithm required for this is specified.
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公开(公告)号：DE59407842D1
公开(公告)日：1999-04-01
申请号：DE59407842
申请日：1994-12-05
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: Fibre-optic sensors are used in reflection or transmission mode in almost all fields of measuring technology, among others, for monitoring industrial plants, in medical diagnostics and in aerospace. In these applications, the effects of mechanical, electrical, magnetic, acoustic, thermal and chemical signals are analysed. To provide for simpler signal analysis, laser light is coupled from a light source (1) into an optical feed line fibre (2) parallel to one of its two major axes. In a first splice (3), the light is introduced into a first optical reference fibre (4), the major axes of which are rotated by 45 DEG compared with those of the optical feed line fibre (2). In a second splice (5), the light passes into a second optical reference fibre (6) which has the same length as the first optical reference fibre (4) and which is rotated by 90 DEG with its major axes with respect to the first optical reference fibre (4). At a third splice (7), the light is coupled into an optical fibre (8) with low birefringence, which first forms a lambda /4 optical fibre loop (9) and then an optical sensor (10). The phase shift of the light can be statically or dynamically influenced by means of a phase modulator (M) in conjunction with the first optical reference fibre (4).
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公开(公告)号：DE4344855C2
公开(公告)日：1997-07-10
申请号：DE4344855
申请日：1993-12-29
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: In order to make evaluation of polarisation-modulated light signals independent of temperature, direct and alternating parts of light-power signals (S1, S2) are evaluated separately. The algorithm required for this is specified.
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公开(公告)号：BR9405284A
公开(公告)日：1995-09-19
申请号：BR9405284
申请日：1994-12-28
Applicant: ABB RESEARCH LTD
Inventor： MEIER MARKUS DR
Abstract: In order to make evaluation of polarisation-modulated light signals independent of temperature, direct and alternating parts of light-power signals (S1, S2) are evaluated separately. The algorithm required for this is specified.
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