Measurement Device for Measuring Light, Measurement System and Measurement Method for Detecting Light Parameters

Abstract

The invention relates to a measurement device (10) for measuring light (200) from a light source (2), comprising an optical unit (30) with a delay element (31) for splitting a polarized light beam (210) of the light (200) into a first partial beam (211) and a second partial beam (212), which have a defined phase shift relative to one another. Furthermore, the invention relates to a measurement system (1), as well as a measurement method (100).

Claims

1. A measurement device for measuring light of a light source comprising an optical unit for splitting a polarized light beam of the light into a first partial beam and a second partial beam, which have a defined phase shift relative to one another, and a sensor unit having at least two detector elements, each having a polarization with a different orientation about an optical axis, wherein the first and second partial beams can be aligned to one another on the detector elements by the optical unit in order to detect interference of the first and second partial beams by the detector elements.

2. The measurement device according to claim 1, wherein the optical unit comprises at least one delay element.

3. The measurement device according to claim 1, wherein the measurement device has a polarization element for influencing a polarization of the light for the polarized light beam.

4. The measurement device according to claim 1, wherein the polarization element is configured to generate at least a linear or random polarization of the light beam.

5. The measurement device according to claim 1, wherein a channeling unit for at least channeling or discretizing the light depending on the received light is provided, which is optically connected upstream of the optical unit.

6. The measurement device according to claim 1, wherein the channeling unit has a channeling element in the form of an optical fiber for channeling the light (200).

7. The measurement device according to claim 1, wherein the channeling unit comprises at least a collimator or a pinhole for forming a beam path of the light.

8. The measurement device according to claim 1, wherein the sensor unit has three or more detector elements.

9. The measurement device according to claim 1, wherein the sensor unit has an electrical measurement output for at least outputting a modulation of a signal or for outputting data points for modulating a signal depending on the interference.

10. The measurement device according to claim 1, wherein the sensor unit has an evaluation circuit in which the detector elements for detecting the interference are connected, the evaluation circuit being configured to provide at least the signal or the data points by means of a multiplexing method.

11. The measurement device according to claim 1, wherein the detector elements are attached in a layer-like manner on a printed circuit board of the sensor unit.

12. The measurement device according to claim 1, wherein at least the sensor unit or the detector elements are configured to be rotatable relative to the optical unit for adjusting the measurement device.

13. A measurement system for detecting light parameters of light from a light source comprising a measurement device, according to claim 1, which comprises an optical unit for splitting a polarized light beam of the light into a first partial beam and a second partial beam, which have a defined phase shift relative to one another, and a sensor unit having at least two detector elements, which each have a polarization with a different orientation about an optical axis, wherein the first and second partial beams are alignable to one another by the optical unit to the detector elements to detect interference of the first and second partial beams by the detector elements, wherein an evaluation unit is provided for evaluating the interference to detect light parameters of the light.

14. The measurement system according to claim 13, wherein the evaluation unit is configured for determining the light parameters in the form of a wavelength of the light depending on a phase of the interference, a bandwidth of the light depending on of at least an amplitude of the interference or a power of the light depending on a mean value of the interference.

15. A measurement method for detecting light parameters of light from a light source by a measurement system according to claim 13, comprising: Receiving light from a light source, Splitting a polarized light beam of the light into a first partial beam and a second partial beam, which have a defined phase shift with respect to one another, Generating interference depending on of the first and second partial beams, Detecting light parameters of light depending on an interference.

Description

[0037] Further advantages, features and details of the invention will be apparent from the following description, in which embodiments of the invention are described in detail with reference to the drawings. In this connection, the features mentioned in the claims and in the description may each be essential to the invention individually or in any combination. It schematically shows:

[0038] FIG. 1 a measurement system according to the invention with a measurement device according to the invention in a first embodiment,

[0039] FIG. 2 an exploded view of the measurement system with the measurement device,

[0040] FIG. 3 a measurement method for detecting light parameters of light from a light source of the measurement system,

[0041] FIG. 4 an electrical signal from a sensor unit of the measurement device, and

[0042] FIGS. 5+6 further configuration options of the measurement device.

[0043] In the following description of some embodiments of the invention, the identical reference signs are used for the same technical features even in different embodiments.

[0044] FIG. 1 shows a measurement system 1 according to the invention for detecting 104 light parameters 201 of light 200 from a light source 2. The light source 2 can be, for example, a laser or a Fiber Bragg grating. In this case, the light source 2 can be characterized by the measurement system 1 on the basis of the light parameters 201 itself. However, especially if the light source 2 is a Fiber Bragg grating, the light parameters 201 may also be able to detect an external effect, such as a stretch or a change in stretch of a component. The light source 2 may be integrated into the measurement system 1, or may be provided externally to the measurement system 1 and emit only the light 200 in the direction of the measurement system 1. A measurement method 100 according to the invention for detecting the light parameters 201 of the light 200 of the light source 2 by the measurement system 1 is shown in FIG. 3 in a schematic representation of method steps/stages. The measurement method 100 is explained below in connection with the measurement system 1.

[0045] For measuring the light 200 of the light source 2, the measurement system 1 comprises a measurement device 10 according to the invention. The measurement device 10 comprises an optical unit 30 for splitting 102 a polarized light beam 210 of the light 200 into a first partial beam 211 and a second partial beam 212. It is conceivable that the light source 2 itself already emits polarized light 200, in particular linearly polarized light, so that the light beam 210 is already polarized when it enters the optical unit 30. The splitting 102 of the light beam 210 by the optical unit 30 takes place in such a way that the first and second partial beams 201, 202 have a defined phase shift relative to one another.

[0046] For detecting an interference 204 of the first and second partial beams 211, 212, the measurement device 10 comprises a sensor unit 40. The first and second partial beams 211, 212 are shown separately in FIG. 1 for improved representation, but may leave the optical unit 30 directionally, parallel and/or concentrically, whereby the first and second partial beams 211, 212 interfere in the area of the sensor unit 40, i.e., in particular, the generation 103 of the interference 204 occurs. The resulting interference 204 of the first and second partial beams 211, 212 can be detected by the sensor unit 40. Preferably, the measurement device 10 comprises a housing 11 in which the optical unit 30 and the sensor unit 40 are arranged.

[0047] For evaluating the interference 204 to detect 104 the light parameters 201 of the light 200, the measurement system 1 has an evaluation unit 50 that is connected to the sensor unit 40. The evaluation unit 50 may comprise, for example, a processor and/or a microprocessor.

[0048] FIG. 2 shows a more detailed embodiment of the measurement device 10, wherein the measurement device 10 comprises a lens 33 for receiving 101 the light 200 from the light source 2. This may generate the light beam 210, which may be initially non-linearly polarized or non-polarized (shown here as dashed) depending on the light source 2. The lens 33 may form an input to the housing 11 of the measurement device 10.

[0049] Furthermore, the measurement device 10 comprises a channeling unit 20 for channeling and/or discretizing the light 200 depending on the received light 200. The channeling unit 20 may be optically connected upstream of the optical unit 30. In particular, the channeling unit 20 is configured to convert the received light 200 into a single-channel light 200. For this purpose, the channeling unit 20 has, for example, a channeling element 21 in the form of an optical fiber, in particular in the form of a single mode fiber, for channeling the light 200. Light information of the light 200 can thus be reduced by the channeling element 21. For example, a plurality of present light parameters 201 of the light 200 can be reduced.

[0050] In particular, when the light 200 from the light source 2 is initially unpolarized, the measurement device 10, in particular the optical unit 30, further comprises a polarization element 32 for influencing a polarization of the light 200 for the polarized light beam 210. The polarization element 32 may be configured, for example, for generating a linear and/or random polarization of the light beam 210. This may create a prerequisite for splitting the polarized light beam 210 into the first and second partial beams 211, 212 with subsequent interference 204.

[0051] For splitting 102 the polarized light beam 210 into the first and second partial beams 211, 212 with the defined phase shift, the optical unit 30 has at least one delay element 31, in particular in the form of a birefringent medium, such as a crystal. In particular, the first partial beam 211 may also be referred to as an ordinary beam and the second partial beam 212 as an extraordinary beam and/or the first partial beam 211 as a slow beam and the second partial beam 212 as a fast beam or vice versa. It may be provided that the optical unit 30 comprises a plurality of delay elements 31 optically connected in series to generate the first and second partial beams 211, 212.

[0052] As shown in FIG. 2, the sensor unit 40 has two or more, in this case four, detector elements 41. Detector elements 41 are arranged in a pattern. The pattern can be configured as a regular pattern. In this case, the first and second partial beams 211, 212 can be aligned to one another with the detector elements 41 by the optical unit 30. An optical axis 203, in particular of the light beam 210 and/or of the optical unit 30, is preferably aligned with the pattern in such a way that an intensity of the first and second partial beams 211, 212 can be distributed uniformly to the detector elements 41. For example, the optical axis 203 may be alignable or aligned centered with respect to the pattern. In the present embodiment of FIG. 2, the detector elements 41 are arranged in a matrix-like pattern, in particular in a 2×2 pattern.

[0053] As shown in FIG. 5, the channeling unit 20 may further include a collimator 22 for shaping and/or parallelizing a beam path of the light 200. The collimator 22 may generate a parallel or nearly parallel beam path of the light 200, and thus preferably a linear or nearly linear guidance of the light 200, to improve the alignment of the light beam 210. In addition or alternatively to the collimator 22, the channeling unit 20 may comprise a pinhole.

[0054] Additionally or alternatively, it can be provided that the detector elements 41 are arranged next to one another in rows, as shown in FIG. 6. In this case, an unequal distribution of the first and second partial beams 211, 212 and/or of the intensity of the first and second partial beams 211, 212 can be determined and/or calculated out by an adjustment process, e.g. by the evaluation unit 50.

[0055] The detector elements 41 further each have a polarization 202 with a respective different orientation about the optical axis 203. Thus, the sensor unit 40 with the four detector elements 41 also comprises four different polarizations 202. For this purpose, for example, one polarizer can be integrated in each of the detector elements 41. It may be provided that the sensor unit 40 and/or the detector elements 41 are configured to be rotatable relative to the optical unit 30 for adjusting the measurement device 10. Additionally or alternatively, the detector elements 41 may be attached in a layer-like manner to a printed circuit board 44 of the sensor unit 40, in particular printed thereon.

[0056] Furthermore, the sensor unit 40 comprises an evaluation circuit 42 through which the detector elements 41 are connected for detecting the interference 204. For outputting a signal 205, the sensor unit 40 further comprises an electrical measurement output 43 for outputting a modulation of the signal 205 and/or of data points 205.1 for modulating the signal 205 depending on the interference 204. For this purpose, the evaluation circuit 42 is configured to provide the signal 205 and/or the data points 205.1 in a multiplexing method, in particular in the form of a space multiplexing method. The evaluation circuit 42 may in particular be arranged on the printed circuit board 44, for example on a rear side of the printed circuit board 44.

[0057] The signal 205 is shown in FIG. 4. A signal intensity 205.2 is plotted against a signal phase 205.3. The signal intensity 205.2 and the signal phase 205.3 may be represented in the signal in terms of electrical current parameters and/or time. For example, the signal intensity 205.2 may be represented by a current and/or a voltage at the measurement output 43 and/or may be proportional to an intensity of the light 200. The signal phase 205.3 may be expressed by the readout of one of the detector elements 41 and/or a time in the multiplexing method. The evaluation unit 50 is thereby configured to determine the light parameters 201 in the form of a wavelength of the light 200 depending on a phase 204.1 of the interference 204, in the form of a bandwidth of the light 200 depending on an amplitude 204.2 of the interference 204, and/or in the form of a power of the light 200 depending on a mean value 204.3 of the interference 204. For this purpose, the signal 205 can be evaluated by the evaluation unit 50.

[0058] By aligning the first and second light beams 210 to one another, the complexity of the measurement device 10 can be reduced by performing the measurement of the light 200 based on the light beam 210, in particular a single light beam 210. It has thus been recognized in the context of the invention that an evaluation of reduced light information is sufficient for many applications. As a result, the complexity of the measurement system 1 with the measurement device 10 can be reduced and the robustness of the measurement method 100 with respect to environmental influences can be increased.

[0059] The foregoing explanation of the embodiments describes the present invention exclusively in the context of examples. Of course, individual features of the embodiments can be freely combined with each other, provided that this is technically reasonable, without leaving the scope of the present invention.

LIST OF REFERENCE SIGNS

[0060] 1 Measurement system [0061] 2 Light source [0062] 10 Measurement device [0063] 11 Housing [0064] 20 Channeling unit [0065] 21 Channeling element [0066] 22 Collimator [0067] 30 Optical unit [0068] 31 Delay element [0069] 32 Polarization element [0070] 33 Lens [0071] 40 Sensor unit [0072] 41 Detector elements [0073] 42 Evaluation circuit [0074] 43 Measurement output [0075] 44 Circuit board [0076] 50 Evaluation unit [0077] 100 Measurement method [0078] 200 Light [0079] 201 Light parameters [0080] 202 Polarization [0081] 203 Axis [0082] 204 Interference [0083] 204.1 Phase [0084] 204.2 Amplitude [0085] 204.3 Mean value [0086] 205 Signal [0087] 205.1 Data point [0088] 205.2 Signal intensity [0089] 205.3 Signal phase [0090] 210 Light beam [0091] 211 First partial beam [0092] 212 Second partial beam