OPTICAL WAVEGUIDE FOR A MAGNETO-OPTICAL CURRENT SENSOR

Abstract

An optical waveguide for a magneto-optical current sensor. The optical waveguide includes a first end surface, through which light can be coupled into the optical waveguide, and a second end surface, through which light can be coupled out of the optical waveguide, wherein at least one of the two end surfaces has an anti-reflective coating.

Claims

1. An optical waveguide for a magnetooptical current sensor, the optical waveguide comprising: a first end face, through which light can be coupled into the optical waveguide, and a second end face, through which light can be decoupled from the optical waveguide, wherein at least one of the first or second end faces has an antireflective coating.

2. The optical waveguide as claimed in claim 1, further comprising: at least one antireflective layer, which is arranged between two optical waveguide sections having indices of refraction different from one another.

3. The optical waveguide as claimed in claim 1, wherein the optical waveguide is manufactured at least in sections from glass.

4. The optical waveguide as claimed in claim 3, wherein at least one antireflective layer is arranged between two optical waveguide sections, which are manufactured from glasses different from one another having indices of refraction different from one another.

5. The optical waveguide as claimed in claim 3 at least one adhesive layer, by which two optical waveguide sections manufactured from glasses different from one another and having indices of refraction different from one another are adhesively bonded to one another, wherein the adhesive layer has an index of refraction which is between the indices of refraction of the two optical waveguide sections.

6. The optical waveguide as claimed in claim 1, wherein the optical waveguide is designed at least in sections as a fiber-optic optical waveguide.

7. The optical waveguide as claimed in claim 6, wherein at least one antireflective layer is arranged between two optical waveguide sections, which are designed as fiber-optic optical waveguides different from one another.

8. The optical waveguide as claimed in claim 6, wherein at least one end face, which has an antireflective coating, is an end face of a fiber-optic optical waveguide.

9. The optical waveguide as claimed in claim 6, wherein at least one end face, which has an antireflective coating, is an end face of a ferrule of a fiber-optic optical waveguide.

10. A magnetooptical current sensor for detecting an amperage of an electrical current in a current conductor, the current sensor comprising: at least one optical waveguide as claimed in claim 1 arranged in an area of the current conductor.

11. The magnetooptical current sensor as claimed in claim 10, wherein at least one optical waveguide extends in a ring shape around the current conductor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above-described properties, features, and advantages of this invention and the manner in which they are achieved will be more clearly and unambiguously comprehensible in conjunction with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. In the drawings:

[0019] FIG. 1 shows a first exemplary embodiment of a magnetooptical current sensor,

[0020] FIG. 2 shows a detail of an optical waveguide having two optical waveguide sections and an adhesive layer,

[0021] FIG. 3 shows a second exemplary embodiment of a magnetooptical current sensor,

[0022] FIG. 4 shows a detail of an optical waveguide having two optical waveguide sections and an antireflective layer.

DETAILED DESCRIPTION OF INVENTION

[0023] Parts corresponding to one another are provided with the same reference signs in the figures.

[0024] FIG. 1 (FIG. 1) shows a first exemplary embodiment of a magnetooptical current sensor 1 for detecting an amperage of an electrical current in a current conductor 2. The current transducer 1 comprises a light coupling unit 3, a first exemplary embodiment of an optical waveguide 5, and a light decoupling unit 7.

[0025] The light coupling unit 3 has an input collimator 9 and a linear input polarizer 11. The input collimator 9 is configured to bundle light of a light source (not shown), for example of a light-emitting diode. The input polarizer 11 polarizes light so that linearly polarized light is supplied to the optical waveguide 5.

[0026] The optical waveguide 5 is configured to supply light supplied thereto from the light coupling unit 3 to the light decoupling unit 7. The optical waveguide 5 displays the Faraday effect. When a current flows in the current conductor 2, the polarization direction of the light is rotated during the passage of the optical waveguide 5 due to the Faraday effect.

[0027] The light decoupling unit 7 has an output polarizer 13 and a linear output collimator 15. A fraction of the light output by the optical waveguide 5 is transmitted by the output polarizer 13 which is parallel to a polarization axis of the output polarizer 13. The output collimator 15 bundles the light transmitted by the output polarizer 13 and supplies it to a photodetector (not shown). The photodetector is configured to detect the light intensity of the light supplied thereto. For example, the photodetector is designed as a photodiode. The amperage of the electrical current through the current conductor 2 is determined on the basis of the light intensity detected by the photodetector.

[0028] The optical waveguide 5 of this exemplary embodiment is designed as a glass ring which extends in a ring shape around the current conductor 2. The current conductor 2 extends orthogonally to the plane of the drawing of FIG. 1. The optical waveguide 5 is formed by four optical waveguide sections 17 to 20, which are each formed as a prismatoid from glass. A first optical waveguide section 17 extends from the light coupling unit 3 to a second optical waveguide section 18. The second optical waveguide section 18 extends between the first optical waveguide section 17 and a third optical waveguide section 19. The third optical waveguide section 19 extends between the second optical waveguide section 18 and the fourth optical waveguide section 20. The fourth optical waveguide section 20 extends from the third optical waveguide section 19 to the light decoupling unit 7. A longitudinal axis of the first optical waveguide section 17 is orthogonal to longitudinal axes of the second optical waveguide section 18 and the fourth optical waveguide section 20 and parallel to a longitudinal axis of the third optical waveguide section 19.

[0029] An end face 21, facing toward the light coupling unit 3, of the first optical waveguide section 17, which is orthogonal to the plane of the drawing of FIG. 1, has a first antireflective coating 31. An end face 22 of the first optical waveguide section 17 opposite to this end face 21 is tilted in relation to the plane of the drawing of FIG. 1 by 45° (see also FIG. 2 in this regard). Light which runs through the first optical waveguide section 17 along the longitudinal axis of the first optical waveguide section 17 is totally reflected toward the second optical waveguide section 18 at the end face 22. In the second optical waveguide section 18, the light is incident on an end face 23 (see FIG. 2) of the second optical waveguide section 18, which is also tilted by 45° in relation to the plane of the drawing of FIG. 1, and light is deflected by total reflection in parallel to the longitudinal axis of the second optical waveguide section 18. Accordingly, the light is guided from the second optical waveguide section 18 to the third optical waveguide section 19 and from the third optical waveguide section 19 to the fourth optical waveguide section 20. An end face 24, facing toward the light decoupling unit 7, of the fourth optical waveguide section 20, which is orthogonal to the plane of the drawing of FIG. 1, has a second antireflective coating 32.

[0030] The first antireflective coating 31 increases the light intensity of the light coupled into the optical waveguide 5 by approximately 10 to 20% in relation to an embodiment of the optical waveguide 5 without the first antireflective coating 31. The second antireflective coating 32 increases the light intensity of the light decoupled from the optical waveguide 5 by approximately 10 to 20% in relation to an embodiment of the optical waveguide 5 without the second antireflective coating 32. Furthermore, the second antireflective coating 32 reduces reflections of light at the end face 24 which reflect light back into the optical waveguide 5.

[0031] FIG. 2 (FIG. 2) shows an optical waveguide 5 embodied similarly to FIG. 1 in an area in which the first optical waveguide section 17 borders the second optical waveguide section 18. In this example, the first optical waveguide section 17 and the second optical waveguide section 18 are manufactured from glasses different from one another, which have indices of refraction different from one another. The first optical waveguide section 17 and the second optical waveguide section 18 are adhesively bonded to one another by an adhesive layer 33, which has an index of refraction which is between the indices of refraction of the two optical waveguide sections 17, 18. Reflections of light during the passage from the first optical waveguide section 17 into the second optical waveguide section 18 are thus advantageously reduced in relation to an embodiment of the optical waveguide 5 without the adhesive layer 33.

[0032] FIG. 3 (FIG. 3) shows a second exemplary embodiment of a magnetooptical current sensor 1 for detecting an amperage of an electrical current in a current conductor 2. This exemplary embodiment has an optical waveguide 5, which is designed as a fiber-optic optical waveguide and extends with a plurality of turns in a ring shape around the current conductor 2. The ends of the optical waveguide 5 each have a ferrule 41, 42. Each ferrule 41, 42 has an end face 21, 24 having an antireflective coating 31, 32.

[0033] FIG. 4 (FIG. 4) shows a detail of an optical waveguide 5 for a magnetooptical current sensor 1, which has optical waveguide sections 43, 44 having indices of refraction different from one another. For example, the optical waveguide sections 43, 44 are manufactured from different glasses from one another or are formed by fiber-optic optical waveguides different from one another. An antireflective layer 45 is arranged between two adjoining optical waveguide sections 43, 44, which reduces reflections of light during the passage of light between the optical waveguide sections 43, 44 in relation to an embodiment of the optical waveguide 5 without the antireflective layer 45.

[0034] Although the invention was illustrated and described in more detail by preferred exemplary embodiments, the invention is not thus restricted by the disclosed examples and other variations can be derived therefrom by a person skilled in the art without leaving the scope of protection of the invention.