Device and method for generating a signal for illuminating a fibre bragg grating in a fibre bragg grating sensor

Abstract

The invention relates to a device (102, 402, 502, 602, 702, 802) for generating a signal (103) for illuminating a fibre Bragg grating (101) in a fibre Bragg grating sensor (10), in particular for detecting traction axes, wherein the device (102, 402, 502, 602, 702, 802) comprises a pump laser (109), a laser medium (110), in particular an erbium-doped fibre amplifier, and a chirped fibre Bragg grating (111), wherein the pump laser (109) is designed to pump the laser medium (110) for emitting light, wherein the chirped fibre Bragg grating (111) is designed to reflect a portion of the light into the laser medium (110), wherein the laser medium (110) is designed to amplify the portion of the light for the signal (103) for illuminating the fibre Bragg grating (101) in the fibre Bragg grating (10). The invention also relates to a method for generating the signal (103).

Description

[0001]Applicant: Hitachi Rail GTS Deutschland GmbH, Thalesplatz 1, 71254 Ditzingen, 15710003WO, 06.08.2025, MKR / MAI. Title: Device and method for generating a signal for illuminating a fiber Bragg grating in a fiber Bragg grating sensor. Description: The invention relates to a device and a method for generating a signal for illuminating a fiber Bragg grating in a fiber Bragg grating sensor, in particular for the detection of train axles. With a fiber Bragg grating sensor, changes in strain due to static or dynamic mechanical loads or temperature changes can be detected. The fiber Bragg grating sensor comprises a fiber Bragg grating arranged in an optical fiber. The measuring principle of the fiber Bragg grating sensor is based on the fact that any change in the effective refractive index or the grating period of the fiber Bragg grating results in a shift of the Bragg wavelength.The change in Bragg wavelength as a function of load or temperature change can be determined by the following equation: where ^^^^^ / ^^ represents the thermo-optic coefficient, ^Λ / ^^ the thermal expansion of the fiber, ^^^^^ / ^^ the variation of the effective refractive index due to the load, and ^Λ / ^^ the change in the grating period. For the detection of tensile axes, the ability of the fiber Bragg grating sensor to measure strain changes is of particular interest, since the force introduced into the rail by a tensile axis leads to a temporal strain. To detect this strain, the fiber Bragg grating is attached to the side of the rail, for example, such that the fiber Bragg grating extends along the side of the rail at an angle of 45° to the surface through which the force is introduced into the rail.To build a measurement system that uses a fiber Bragg grating as a sensor element, a fiber Bragg grating interrogation technique is required to convert the spectral coding of the fiber Bragg grating into an electrical signal containing the necessary information about the measurement quantity. An example of a passive interrogation technique is passive edge filtering. The basic principle of this technique is to convert the Bragg wavelength shift into an easily detectable power shift. To achieve this conversion, either a linear wavelength-dependent light source or a broadband light source in combination with a linear wavelength-dependent optical component is used.The device for generating a signal for illuminating a fiber Bragg grating in a fiber Bragg grating sensor, particularly for detecting pull axes according to claim 1, provides a linearly wavelength-dependent light source for passive edge filtering. The device comprises a pump laser, a laser medium, in particular an erbium-doped fiber amplifier, and a chirped fiber Bragg grating. The pump laser is configured to pump the laser medium to emit light, the chirped fiber Bragg grating is configured to reflect a portion of the light into the laser medium, and the laser medium is configured to amplify the portion of the light to provide a signal for illuminating the fiber Bragg grating in the fiber Bragg grating sensor. This means that the device uses the portion of the light reflected from the chirped fiber Bragg grating to generate the signal for querying the fiber Bragg grating in the fiber Bragg grating sensor.The device enables reliable scanning of the fiber Bragg grating in the fiber Bragg grating sensor with a sampling rate high enough to detect trains traveling at speeds of up to 400 km / h. This makes the device particularly suitable for train axle detection. Preferably, the laser medium is configured to emit broadband light from a wavelength range, in particular from 1500 nm to 1580 nm, wherein the chirped fiber Bragg grating is configured to reflect light with wavelengths from this range, in particular between 1538 nm and 1555 nm. This means that the wavelength range encompasses different wavelengths that are reflected by the chirped fiber Bragg grating (Figure 3).Preferably, the device is configured to generate the signal (103, example see Figure 2) with a spectral power density ^^^^(^)^ which has at least one of the following advantageous properties: - the spectral width (Δ^) of the wavelength range is greater than or equal to the measuring range of the fiber Bragg grating sensor, - the spectral power density curve over the wavelength is strictly monotonic in the wavelength range or has a constant slope (Δ^^^ / Δ^), - the spectral power density curve over the wavelength has a rising or falling edge in the wavelength range, - the slope of the spectral power density is adjustable depending on a pump current with which the pump laser is operated. This means, 1) the spectral power density has a sufficiently large spectral width Δ^ in the wavelength range for interrogation over the measuring range.For example, the wavelength range has the required spectral width Δ^ for the sensor's measuring range, 2) the spectral power density exhibits sufficiently high linearity in the wavelength range for interrogation, 3) the spectral power density exhibits a rising or falling edge in the wavelength range, in particular an edge that is sufficiently large for interrogation of the fiber Bragg grating sensor, in which the fiber Bragg grating has a predetermined refractive index, 4) the slope of the spectral power density is adjustable depending on the pump current ^ with which the pump laser is operated. The pump laser can be operated, for example, with different pump currents. …operable, resulting in different slopes of the spectral power density. For example (Figure 4), the chirped fiber Bragg grating is arranged between the pump laser and the laser medium, wherein the laser medium is pumpable with light of a wavelength, in particular 980 nm or 1480 nm, wherein the pump laser is configured to generate the light with the wavelength, and wherein the chirped fiber Bragg grating is configured to transmit light with the wavelength. For example (Figure 5), the device comprises a wavelength multiplexer, wherein the laser medium is arranged between the wavelength multiplexer and the chirped fiber Bragg grating. This represents an arrangement in which the reflected part of the light is amplified by the laser medium and then passes to the wavelength multiplexer.The device may include an additional laser medium (Figure 6), wherein the device is configured to output the signal for illuminating the fiber Bragg grating in the fiber Bragg grating sensor via the additional laser medium. For example (Figure 7), the device includes a wavelength multiplexer, wherein the wavelength multiplexer is arranged between the pump laser and the laser medium and between the laser medium and the chirped fiber Bragg grating. The device may also include an additional laser medium (Figure 8), wherein the additional laser medium is arranged between the wavelength multiplexer and the chirped fiber Bragg grating. Preferably, the device includes an isolator, wherein the device is configured to output the signal for illuminating the fiber Bragg grating in the fiber Bragg grating sensor via the isolator.A method for generating a signal to illuminate a fiber Bragg grating of a fiber Bragg grating sensor, particularly for detecting train axes, involves pumping a laser medium, especially an erbium-doped fiber amplifier, with a pump laser to emit light. A portion of the light is reflected back into the laser medium by a chirped fiber Bragg grating, and this portion is amplified by the laser medium to provide the signal for illuminating the fiber Bragg grating in the fiber Bragg grating sensor. Preferably, broadband light from a wavelength range of 1500 nm to 1580 nm is emitted from the laser medium, and light with wavelengths from this range, particularly between 1538 nm and 1555 nm, is reflected back by the chirped fiber Bragg grating.Preferably, the signal is generated with a spectral power density that exhibits at least one of the following properties: - the spectral width of the wavelength range is greater than or equal to the measuring range of the fiber Bragg grating sensor, - the spectral power density curve is strictly monotonic or has a constant slope in the wavelength range, - the spectral power density curve has a rising or falling edge in the wavelength range, - the slope of the spectral power density is adjustable depending on the pump current used to operate the pump laser. The method may include the arrangement of the chirped fiber Bragg grating between the pump laser and the laser medium, wherein the laser medium is supplied with light of a wavelength, in particular 970 nm to 985 nm, e.g.The laser medium is pumped at 980 nm or 1480 nm, with the pump laser generating the light at the wavelength, and the chirped fiber Bragg grating transmitting the light at the wavelength. The method may include the arrangement of the laser medium between a wavelength multiplexer and the chirped fiber Bragg grating. It may also include the arrangement of a wavelength multiplexer between the pump laser and the laser medium, and between the laser medium and the chirped fiber Bragg grating. Preferably, the signal for illuminating the fiber Bragg grating in the fiber Bragg grating sensor is output via an isolator. Further advantageous embodiments are described below and shown in the drawing. The drawing shows: Fig.Fig. 1 A schematic representation of a fiber Bragg grating measuring system with a fiber Bragg grating in a fiber Bragg grating sensor and a device for generating a signal to illuminate the fiber Bragg grating, Fig. 2 an exemplary spectral power density, Fig. 3 an exemplary reflectivity spectrum of a chirped fiber Bragg grating, Fig. 4 a schematic representation of an exemplary first embodiment of the device, Fig. 5 a schematic representation of an exemplary second embodiment of the device, Fig. 6 a schematic representation of an exemplary third embodiment of the device, Fig. 7 a schematic representation of an exemplary fourth embodiment of the device, Fig. 8 a schematic representation of an exemplary fifth embodiment of the device and Fig. 9 a flowchart with steps of a method for generating the signal.Figure 1 schematically depicts a fiber Bragg grating measuring system 100 with a fiber Bragg grating 101 in a fiber Bragg grating sensor 10 and a device 102 for generating a signal 103 to illuminate the fiber Bragg grating 101. The sensor itself is not shown in Figure 1. The sensor is, for example, a mechanical device that includes the fiber Bragg grating 101. The fiber Bragg grating measuring system 100 can be used, for example, for the detection of tensile axes. The fiber Bragg grating measuring system 100 comprises a wavelength multiplexer 104, which is arranged between the device 102 and the fiber Bragg grating 101 of the fiber Bragg grating measuring system 100. The fiber Bragg grating 101 is arranged in an optical fiber and has a refractive index modulation along the optical fiber.The refractive index modulation determines which wavelengths the fiber Bragg grating 101 transmits as the transmitted part 105 of the signal and which wavelength the fiber Bragg grating 101 reflects as the reflected part 106 of the signal 103. The fiber Bragg grating 101 is manufactured with a refractive index modulation that, without any mechanical stress acting on the fiber Bragg grating 101, reflects a predetermined wavelength from the fiber Bragg grating 101 at a given temperature. The measuring range of the fiber Bragg grating measuring system 100 depends on a wavelength range in which the fiber Bragg grating 101 reflects light due to the refractive index modulation, which changes depending on the mechanical stress and / or the temperature.According to a first example, the fiber Bragg grating 101 is designed to reflect light with a wavelength in a first wavelength range between 1547 nm and 1562 nm, depending on a mechanical load and / or the temperature in the measurement range. The fiber Bragg grating 101 is, for example, manufactured with a refractive index modulation for the reflection of light with a wavelength of 1554 nm. According to a second example, the fiber Bragg grating 101 is designed to reflect light with a wavelength in a second wavelength range between 1538 nm and 1555 nm, depending on a mechanical load and / or the temperature in the measurement range. The fiber Bragg grating 101 is, for example, manufactured with a refractive index modulation for the reflection of light with a wavelength of 1549 nm.The fiber Bragg grating measuring system 100 comprises a device 107 configured to convert the reflected part 106 of the signal 103 into an electrical signal 108, which characterizes the power of the reflected part 106 of the signal 103. A power shift can be read from a change in the electrical signal 108, which results from a Bragg wavelength shift in the fiber Bragg grating 101 due to the refractive index modulation in the fiber Bragg grating 101 caused by load or temperature change. The device 102 for generating the signal 103 for illuminating the fiber Bragg grating 101 comprises a pump laser 109, a laser medium 110, and a chirped fiber Bragg grating 111. In this example, the laser medium 110 and the pump laser 109 are configured for the optical 980 nm window. The pump laser 109 generates, for example, light with a wavelength of 980 nm. The laser medium 110 comprises, for example, an erbium-doped fiber amplifier. The wavelength of 980 nm is just one example.The laser medium 110 and the pump laser 109 can also be configured for other optical windows, e.g., for the 850 nm window, the 1300 nm window, or the 1550 nm window. Cables with the 850 nm window are relatively inexpensive and are mainly used for short distances. The second optical window exhibits lower attenuation and is therefore suitable for somewhat longer distances. The third optical window is used for long distances to enable extended transmission ranges. Erbium is one example of the type of doping used for the glass fiber in the laser medium 110. Other types of doping, e.g., doping with titanium, chromium, cobalt, neodymium, or ytterbium, can be implemented in a fiber Bragg grating 101 with appropriately adapted refractive index modulation, using a pump laser with a suitable wavelength for excitation.The laser medium 110 is configured to emit light in a wavelength range that includes wavelengths suitable for illuminating the fiber Bragg grating 101 during a measurement with the fiber Bragg grating measuring system 100. Wavelengths suitable for interrogation lie within a wavelength range suitable for interrogation, i.e., in the wavelength range in which the fiber Bragg grating 101 reflects light due to the refractive index modulation in the fiber Bragg grating 101, which changes depending on the mechanical load and / or temperature. In the wavelength range suitable for interrogation, the spectral power density exhibits a rising or falling edge. In the wavelength range suitable for interrogation, the spectral power density additionally exhibits at least one of the following properties: - a linear progression of the rising or falling edge.falling edge, -the spectral width of the wavelength range is greater than or equal to the measuring range of the fiber Bragg grating S. ensors 10,- The spectral power density curve versus wavelength is strictly monotonic or exhibits a constant slope Δ^^^ / Δ^. - The spectral power density curve versus wavelength exhibits a rising or falling edge. - The spectral power density curve versus wavelength exhibits an edge, with a low power fluctuation along the edge. - The slope of the spectral power density is adjustable depending on the pump current used to operate the pump laser. The edge is generated by the combination of the laser medium 110 with the chirped fiber Bragg grating 101. The reflectivity spectrum of the chirped fiber Bragg grating 101 has an influence on this. For example, the reflectivity spectrum is influenced by...The following parameters are relevant: the period of the grating modulation in the chirped fiber Bragg grating 101, the magnitude of the modulation depth of the chirped fiber Bragg grating 101, and the number of grating periods in the chirped fiber Bragg grating 101. The characteristics of the laser medium 110 influence these parameters. For example, the following parameters influence the characteristics: the emission and absorption cross-sections of the laser medium 110, the length of the laser medium 110, and the pumping power. The combination of the laser medium 110 with the chirped fiber Bragg grating 101 constitutes a feedback system, meaning that the portion of the light reflected by the chirped fiber Bragg grating 101 is also amplified. The parameters are determined, for example, in a numerical simulation. It may be provided that the slope of the spectral power density is adjustable depending on a pump current ^ with which the pump 109 is operated.Figure 2 shows an exemplary power spectral density PSD 200 versus wavelength ^. In the wavelength range 201, with wavelength ^ increasing from zero, the power spectral density PSD 200 exhibits a sawtooth waveform with a rising edge followed by a falling edge. The rising edge begins, for example, at 1538 nm. The falling edge ends, for example, at 1552 nm. The chirped fiber Bragg grating 111 is arranged in an optical fiber and exhibits a refractive index modulation along the optical fiber with a variation in the refractive index modulation along the optical fiber. The variation in the refractive index modulation determines which wavelengths the chirped fiber Bragg grating 101 transmits and which wavelengths the chirped fiber Bragg grating 111 reflects. The chirped fiber Bragg grating 111 is designed to reflect a portion of the light, i.e.,Light of the wavelengths reflected by the chirped fiber Bragg grating 111 is reflected into the laser medium 110. The chirped fiber Bragg grating 111 is designed to reflect light with wavelengths from the wavelength range. Figure 3 shows the reflectivity R of the chirped fiber Bragg grating 111 as a percentage of the wavelength ^ in nanometers. The reflectivity R is maximal in the wavelength range 201. In the wavelength range 201, the reflectivity R curve is flat. For example, the reflectivity R for generating the signal 103 with the spectral power density shown in Figure 2 is maximal and flat in the wavelength range 201 between 1540 nm and 1550 nm. Outside the wavelength range 201, the reflectivity R is minimal, i.e., at zero percent.This means that, in the first example, the chirped fiber Bragg grating 111 can be configured to reflect light with wavelengths from the first wavelength range of 1547 nm to 1562 nm. This means that, in the second example, the chirped fiber Bragg grating 111 can be configured to reflect light with wavelengths from the second wavelength range of 1538 nm to 1555 nm. The laser medium 110 is configured to amplify the portion of the light reflected into the laser medium 110 for illumination of the fiber Bragg grating 101 in the fiber Bragg grating sensor. The device 102 provides a light source for the fiber Bragg grating measuring system 100. The light source provides light for the fiber Bragg grating 101 within the measuring range of the fiber Bragg grating measuring system 100. Exemplary embodiments of the device 102 are described below. described. Figure 4 schematically represents an exemplary first embodiment 402 of the device 102.According to the first embodiment 402, the chirped fiber Bragg grating 111 is arranged between the pump laser 109 and the laser medium 110. The laser medium 110 is pumpable with light of wavelength 980 nm. The pump laser 109 is configured to generate light with wavelength 980 nm. The chirped fiber Bragg grating 111 is configured to transmit light with wavelength 980 nm. This means that the chirped fiber Bragg grating 111 is a bandstop filter that reflects light in the stopband of the bandstop filter and transmits all other wavelengths. The device 102 according to the first embodiment 402 has an insulator 112. The device 102 according to the first embodiment 402 is configured to output the signal 103 for illuminating the fiber Bragg grating 101 in the fiber Bragg grating measuring system 100 via the insulator 112. Figure 5 schematically represents an exemplary second embodiment 502 of the device 102.The device 102 according to the second embodiment 502 comprises the pump laser 109, the laser medium 110, the chirped fiber Bragg grating 111, the insulator 112, and a wavelength multiplexer 113. The laser medium 110 is arranged between the wavelength multiplexer 113 and the chirped fiber Bragg grating 111. The laser medium 110 may be the optical link or part of the optical link. Figure 6 schematically represents an exemplary third embodiment 602 of the device 102. The device 102 according to the third embodiment 602 is configured like the device 102 according to the second embodiment 502 and additionally comprises a laser medium 114, which is arranged between the wavelength multiplexer 113 and the insulator 112. It can be provided that the laser medium 114 is the optical connection or part of the optical connection. In the example, the laser medium 114 is configured like the laser medium 110.Figure 7 schematically illustrates an exemplary fourth embodiment 702 of the device 102. The device 102 according to the fourth embodiment 702 comprises the pump laser 109, the laser medium 110, the chirped fiber Bragg grating, the insulator 112, and a wavelength multiplexer 115. The wavelength multiplexer 115 is arranged between the pump laser 109 and the laser medium 110 and between the laser medium 110 and the chirped fiber Bragg grating 111. The laser medium 110 is arranged between the wavelength multiplexer 115 and the insulator 112. The device 102 according to the fourth embodiment 702 is configured to output the signal 103 for illuminating the fiber Bragg grating 101 in the fiber Bragg grating measuring system 100 via the insulator 112. The insulator 112 can, instead of being located inside the device 102, also be located outside the device 102, e.g. between the device 102 and the fiber Bragg grid 101, depending on the specific embodiment.Figure 8 schematically depicts an exemplary fifth embodiment 802 of the device 102. The device 102 according to the fifth embodiment 802 is configured like the device 102 according to the fourth embodiment 702 and additionally comprises a laser medium 116, which is arranged between the wavelength multiplexer 115 and the chirped fiber Bragg grating 111. The laser medium 116 may be the optical link or part of the optical link. In the example, the laser medium 116 is configured like the laser medium 110. In embodiments with two laser media, it may be provided that the two laser media are configured differently from each other, particularly with respect to their lengths. Figure 9 shows a flowchart with steps of a method for generating the signal 103 for illuminating a fiber Bragg grating 101 of the fiber Bragg grating sensor 10 in the fiber Bragg grating measuring system 100, in particular for the detection of train axes.The procedure comprises a step 901. In step 901, the pump current ^ with which the pump laser 109 is operated is specified. Subsequently, a step 902 is executed. This means that the operating point of the pump laser 109 is initially set. Adjustments are made, for example, by adapting the pump current ^ if the operating point deviates too far from the initially set operating point. The sensitivity of the fiber Bragg grating measuring system 100 depends on the slope of the edge of the spectral power density in the wavelength domain and the reflectivity of the fiber Bragg grating 101. The reflectivity of the fiber Bragg grating is proportional to the refractive index modulation and the grating length. The sensitivity is proportional to the product of the slope of the power spectrum in the wavelength domain and the refractive index of the fiber Bragg grating 101. For example, the pump current ^ with which a specified sensitivity is achieved is determined.For example, the pump current ^ with which the specified sensitivity of the fiber Bragg grating measuring system 100 is achieved is determined depending on the slope of the edge of the spectral power density in the wavelength range and / or depending on the reflectivity of the fiber Bragg grating 101. The pump current ^ is determined, for example, depending on the product. The procedure comprises a step 902. In step 9702, the pump laser 109 is operated with the pump current ^. The pump laser 109 pumps the laser medium 110. The laser medium 110 generates light via spontaneous emission. The light from the spontaneous emission is amplified in the laser medium 110. A portion of this amplified spontaneous emission is reflected from the chirped fiber Bragg grating 111 into the laser medium 110. The reflected part of the enhanced spontaneous emission is further amplified by the laser medium 110, thus creating the signal 103 with which the fiber Bragg grating 101 in the fiber Bragg grating sensor 10 is illuminated.The signal 103 exhibits the aforementioned properties, particularly with regard to its edge. This means that the portion of the light amplified by the laser medium 110 from the spontaneous emission in the laser medium 110 is reflected back into the laser medium 110 by the chirped fiber Bragg grating 111 and amplified again. This portion of the light is amplified by the laser medium 110 to form signal 103 for illuminating the fiber Bragg grating 101 in the fiber Bragg grating sensor 10. The signal 103 is generated, for example, by the device 102 according to one of the exemplary embodiments. Subsequently, step 901 is performed. The device 102 and the method are used, for example, for the detection of traction axles. This means that the fiber Bragg grating 101 in the fiber Bragg grating sensor 10 determines a change in strain resulting from a force introduced into a rail by a traction axle. To detect this strain, the fiber Bragg grating 101 is attached to the side of the rail, e.g.The fiber Bragg grid 101 is attached in such a way that it extends along the side of the rail at an angle of 45° to the surface through which the force is introduced into the rail. The fiber Bragg grid 101 is queried, for example, using the device 102.

Claims

Patent Claims 1. Device (102, 402, 502, 602, 702, 802) for generating a signal (103) for illuminating a fiber Bragg grating (101) in a fiber Bragg grating sensor (10), particularly for detecting train axes, characterized in that the device (102, 402, 502, 602, 702, 802) comprises a pump laser (109), a laser medium (110), in particular an erbium-doped fiber amplifier, and a chirped fiber Bragg grating (111), wherein the pump laser (109) is configured to pump the laser medium (110) to emit light, wherein the chirped fiber Bragg grating (111) is configured to reflect part of the light into the laser medium (110), wherein the laser medium (110) is configured is to amplify the portion of the light that serves as the signal (103) for illuminating the fiber Bragg grating (101) in the fiber Bragg grating sensor (10).2.The device (102, 402, 502, 602, 702, 802) according to claim 1, characterized in that the laser medium (110) is configured to emit broadband light from a wavelength range, in particular a wavelength range from 1500 nm to 1580 nm, wherein the chirped fiber Bragg grating (111) is configured to reflect light with wavelengths from the wavelength range, in particular between 1538 nm and 1555 nm. Device (102, 402, 502, 602, 702, 802) according to claim 2, characterized in that the device (102, 402, 502, 602, 702, 802) is configured to generate the signal (103) with a spectral power density that has at least one of the following properties: - the spectral width of the wavelength range is greater than or equal to the measuring range of the fiber Bragg grating S. ensors (10),- the spectral power density curve over the wavelength is strictly monotonic or has a constant slope in the wavelength range, - the spectral power density curve over the wavelength has a rising or falling edge in the wavelength range, - the slope of the spectral power density is adjustable depending on a pump current with which the pump laser (109) is operated.

4. The device (102, 402) according to one of claims 1 to 3, characterized in that the chirped fiber Bragg grating (111) is arranged between the pump laser (109) and the laser medium (110), wherein the laser medium (110) is pumpable with light of a wavelength, in particular 980 nm or 1480 nm, wherein the pump laser (109) is configured to generate the light with the wavelength, and wherein the chirped fiber Bragg grating (111) is configured to transmit light with the wavelength.5.The device (102, 502, 602) according to any one of claims 1 to 3, characterized in that the device (102, 502, 602) comprises a wavelength multiplexer (113), wherein the laser medium (110) is arranged between the wavelength multiplexer (113) and the chirped fiber Bragg grating (111).

6. The device (102, 602) according to claim 5, characterized in that the device (102, 602) comprises an additional laser medium (114), wherein the device (102, 602) is configured to output the signal (103) for illuminating the fiber Bragg grating (101) in the fiber Bragg grating sensor (10) via the additional laser medium (114).

7. The device (102, 702) according to one of claims 1 to 3, characterized in that the device (102, 702) comprises a wavelength multiplexer (115), wherein the wavelength multiplexer (115) is arranged between the pump laser (109) and the laser medium (110) and between the laser medium (110) and the chirped fiber Bragg grating (111).The device (102, 802) according to claim 7, characterized in that the device (102, 802) comprises an additional laser medium (116), wherein the additional laser medium (114) is arranged between the wavelength multiplexer (115) and the chirped fiber Bragg grating (111).

9. The device (102, 402, 502, 602, 702, 802) according to one of the preceding claims, characterized in that the device (102, 402, 502, 602, 702, 802) comprises an insulator (112), wherein the device (102, 402, 502, 602, 702, 802) is configured to output the signal (103) for illuminating the fiber Bragg grating (101) in the fiber Bragg grating sensor (10) via the insulator (112).

10. A method for generating a signal (103) for illuminating a fiber Bragg grating (101) of a fiber Bragg grating sensor (10), in particular for detecting pull axes, characterized in that a laser medium (110), in particular an erbium-doped fiber amplifier, is pumped with a pump laser (109) to emit light, wherein a portion of the light is reflected into the laser medium (110) by a chirped fiber Bragg grating (111), wherein the portion of the light is amplified by the laser medium (110) to form the signal (103) for illuminating the fiber Bragg grating (101) in the fiber Bragg grating sensor (902). 11.The method according to claim 10, characterized in that broadband light from a wavelength range is emitted from the laser medium (110) (902), in particular a wavelength range from 1500 nm to 1580 nm, wherein light with wavelengths from the wavelength range, in particular between 1538 nm and 1555 nm, is reflected by the chirped fiber Bragg grating.

12. The method according to claim 11, characterized in that the signal (103) is generated with a spectral power density having at least one of the following properties: - the spectral width of the wavelength range is greater than or equal to the measuring range of the fiber Bragg grating S. ensors (10),- The spectral power density curve over the wavelength is strictly monotonic or has a constant slope in the wavelength range; - The spectral power density curve over the wavelength has a rising or falling edge in the wavelength range; - The slope of the spectral power density is adjustable depending on the pump current with which the pump laser (109) is operated.

13. The method according to one of claims 10 to 12, characterized in that the chirped fiber Bragg grating (111) is arranged between the pump laser (109) and the laser medium (110), wherein the laser medium (110) is pumped with light of a wavelength, in particular 970 nm to 985 nm, e.g. 980 nm or 1480 nm, wherein the pump laser (109) generates the light with the wavelength, and wherein the chirped fiber Bragg grating (111) transmits the light with the wavelength.The method according to any one of claims 10 to 12, characterized in that the laser medium (110) is arranged between a wavelength multiplexer (113) and the chirped fiber Bragg grating (111).

15. The method according to any one of claims 10 to 12, characterized in that a wavelength multiplexer (115) is arranged between the pump laser (109) and the laser medium (110) and between the laser medium (110) and the chirped fiber Bragg grating (111).

16. The method according to any one of claims 10 to 15, characterized in that the signal (103) for illuminating the fiber Bragg grating (101) in the fiber Bragg grating sensor (10) is output via an isolator (112).

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