Semiconductor laser and method for operating a semiconductor laser

Abstract

The invention relates to a semiconductor laser (10), the semiconductor laser (10) comprising an active region (13) designed to emit laser radiation during operation of the semiconductor laser (10), a ridge region (14) arranged on the active region (13) or comprising at least part of the active region (13), and a grating (15) arranged next to the ridge region (14), wherein the grating (15) comprises an electrochromic material. The invention additionally relates to a method for operating a semiconductor laser (10).

Description

[0001] Description

[0002] Semiconductor laser and a method for operating a semiconductor laser

[0003] A semiconductor laser and a method for operating a semiconductor laser are specified.

[0004] One problem to be solved is to provide a semiconductor laser that can be manufactured efficiently. Another problem to be solved is to provide a method for operating a semiconductor laser, wherein the semiconductor laser can be manufactured efficiently.

[0005] The objects are achieved by the subject matter of the independent patent claims. Advantageous embodiments and further developments are specified in the subclaims.

[0006] According to at least one embodiment of the semiconductor laser, the semiconductor laser comprises an active region configured to emit laser radiation during operation of the semiconductor laser. The active region may have at least one quantum well structure.

[0007] The semiconductor laser can further have a first region which is doped with a first dopant. The first region can comprise one or more doped semiconductor layers. The first region can be formed with a semiconductor material, such as a II IV compound semiconductor material. For example, the first region comprises GaN, InGaN, AlGaN, AlInGaN. The first region can be a three-dimensional body which, for example, has at least approximately the shape of a cuboid or a cylinder. The main extension plane of the first region can run parallel to one of the top surfaces of the cuboid or the cylinder. The first region can be p-doped or n-doped. Thus, the first dopant can be a p-dopant or an n-dopant.

[0008] The semiconductor laser can have a second region doped with a second dopant. The second region can comprise one or more doped semiconductor layers. The second region can be formed with a semiconductor material, such as a II IV compound semiconductor material. For example, the second region comprises GaN, InGaN or InGaP. The second region can be a three-dimensional body which, for example, has at least approximately the shape of a cuboid or a cylinder. The main extension plane of the second region can run parallel to one of the top surfaces of the cuboid or the cylinder. The second region can be p-doped or n-doped. The second dopant can therefore be a p-dopant or an n-dopant.The active region may be arranged in a vertical direction between the first region and the second region, wherein the vertical direction is perpendicular to a main extension plane of the semiconductor laser.

[0009] According to at least one embodiment of the semiconductor laser, the semiconductor laser comprises a ridge region which is arranged on the active region or comprises at least a part of the active region. The ridge region can be doped with the first dopant. The ridge region can have a lower dopant concentration than the first region. Another name for the ridge region can be laser ridge. The active region can be arranged in the vertical direction between a substrate of the semiconductor laser and the ridge region. The ridge region can therefore be arranged in the vertical direction on the active region. Alternatively, at least a part of the active region is part of the ridge region. It is also possible for the ridge region to comprise the active region.

[0010] According to at least one embodiment of the semiconductor laser, the semiconductor laser comprises a grating arranged next to the ridge region. The fact that the grating is arranged next to the ridge region can mean that the grating is arranged in a lateral direction next to the ridge region, wherein the lateral direction runs parallel to the main extension plane of the active region. The grating can have a plurality of grating ridges. The grating ridges can be arranged spaced apart from one another next to the ridge region. The grating ridges can have the same distances from one another. The distance a from a first side of a grating ridge to the first side of an adjacent grating ridge can be given by: where X is the wavelength of the electromagnetic radiation in a vacuum which experiences the least absorption by the grating and n is the effective refractive index of the light field in the material. The semiconductor laser can therefore emit laser radiation with the wavelength X during operation. The wavelength X can be a main emission wavelength of the semiconductor laser. The grating bars can each have the same shape and size. The grating bars can each have the same material composition. The grating bars can form the grating. The grating bars can each have a main extension direction which runs parallel to the main extension plane of the first region. The grating bars can each have the shape of a cuboid. The grating bars can each be formed by a layer. The semiconductor laser can be a distributed feedback (DFB) laser.The grating can therefore be a DFB grating. The grating can have grating bars on two sides next to the bar region. This can mean that grating bars are arranged along a lateral direction on two sides next to the bar region, with the lateral direction running parallel to the main extension plane of the active region. The grating can therefore have two regions with grating bars. These can be arranged on opposite sides of the bar region. The same number of grating bars can be arranged on each of the two sides. The grating bars can have the same shape on both sides. The grating bars can be arranged in the same way on both sides.

[0011] According to at least one embodiment of the semiconductor laser, the grating comprises an electrochromic material. It is also possible for the grating to consist of an electrochromic material. The optical properties such as absorption, reflection and transmission of an electrochromic material can be changed by applying an electrical voltage or an electrical current. According to at least one embodiment of the semiconductor laser, the semiconductor laser comprises an active region which is designed to emit laser radiation during operation of the semiconductor laser, a ridge region which is arranged on the active region or comprises at least part of the active region, and a grating which is arranged next to the ridge region, wherein the grating comprises an electrochromic material.

[0012] The semiconductor laser described here is based, among other things, on the idea that the optical properties of the grating can be adjusted. This can be achieved by applying a voltage to the grating, which has an electrochromic material. The emission properties of a DFB laser depend heavily on the absorption properties of the grating and the overlap of the light field with the grating. These can be influenced by the geometric dimensions of the grating. The standing wave generated in the active region during operation of the semiconductor laser, which has its intensity minima at the positions of the grating bars in the longitudinal direction along the resonator, experiences the lowest absorption by the grating. This is only the case for a very narrow wavelength range, ideally for just one wavelength. In this way, the emission of laser radiation with only one wavelength (spectral orLongitudinal mono-mode emission (LME), one main emission wavelength, or a very narrow wavelength range. Thus, the main emission wavelength depends on the precise geometric dimensions of the grating and the overlap of the light field with the grating. Likewise, the side mode suppression, i.e., the ratio of the intensity of emitted radiation at the main emission wavelength to the intensity of emitted radiation at other wavelengths, depends on the geometric dimensions of the grating.

[0013] However, inaccuracies can occur during manufacture of the grating and the adjacent ridge region. This often means that not all manufactured semiconductor lasers can be used. If the geometric dimensions of the grating and / or the ridge region are inaccurate, the side mode suppression can be undesirably low, or if the absorption by the grating is too great, for example, various parameters of the semiconductor laser can be impaired, such as the threshold or the steepness. By adjusting the absorption properties of the grating, inaccuracies in the manufacturing process can be compensated for afterwards. For example, inaccuracies in the etching depth and width of the ridge region and in geometric dimensions of the grating such as the width and distances between the grating ridges and the ridge region can be compensated for.This can increase the yield of usable semiconductor lasers, resulting in more efficient manufacturing. This can also lead to a reduction in costs.

[0014] According to at least one embodiment of the semiconductor laser, the grating is electrically connected to a first electrical contact. The grating can be in direct contact with the first electrical contact. Each of the grating webs can be electrically connected to the first electrical contact. The first electrical contact can be connected to a DC voltage source. A DC voltage can be applied to the grating via the first electrical contact. This allows the absorption of the grating to be adjusted, which advantageously enables

[0015] Inaccuracies in manufacturing from the same .

[0016] According to at least one embodiment of the semiconductor laser, the first electrical contact is connected to a DC voltage source. The semiconductor laser can comprise the DC voltage source. A DC voltage can be applied to the grating via the first electrical contact. This allows the absorption of the grating to be adjusted, which advantageously makes it possible to compensate for inaccuracies during manufacturing.

[0017] According to at least one embodiment of the semiconductor laser, the first electrical contact is arranged on the grating. The grating can thus be arranged in the vertical direction between the substrate and the first electrical contact. The first electrical contact can be arranged on opposite sides of the ridge region on the grating. This can mean that, if the grating has two regions, the first electrical contact is arranged on both regions of the grating. In this case, the first electrical contact can also have two regions. The first electrical contact can cover the grating. The first electrical contact can completely cover the grating. Thus, each grating ridge can be supplied with electrical voltage, so that the absorption of the grating can be adjusted.

[0018] According to at least one embodiment of the semiconductor laser, the first electrical contact extends along a longitudinal direction along the grating, and the longitudinal direction runs parallel to the main extension plane of the active region. The first electrical contact can extend along the entire grating. Thus, each grating bar can be supplied with electrical voltage, so that the absorption of the grating can be adjusted.

[0019] According to at least one embodiment of the semiconductor laser, a second electrical contact is arranged on an underside of the semiconductor laser. The second region can be arranged closer to the underside than the ridge region. The second electrical contact can partially cover the underside. The second electrical contact can be connected to a DC voltage source. The second electrical contact can be connected to the same DC voltage source as the first electrical contact. The second region can also be electrically connected to the second electrical contact. A DC voltage can be applied to the grating via the first electrical contact and the second electrical contact. This makes it possible to adjust the absorption of the grating, which advantageously makes it possible to compensate for inaccuracies during production.

[0020] According to at least one embodiment of the semiconductor laser, a second electrical contact is in electrical contact with the grating. The second electrical contact can be arranged on the side of the grating which faces away from the first electrical contact. The grating can thus be arranged in the vertical direction between the first electrical contact and the second electrical contact. The second electrical contact can be arranged in the vertical direction between the grating and the substrate. The second electrical contact can be in direct contact with the grating. Each of the grating webs can be electrically connected to the second electrical contact. A passivation layer can be arranged between the first electrical contact and the second electrical contact. The passivation layer can comprise an electrically insulating material. The second electrical contact can be connected to a DC voltage source.The second electrical contact can be connected to the same DC voltage source as the first electrical contact. A DC voltage can be applied to the grating via the first electrical contact and the second electrical contact. This allows the absorption of the grating to be adjusted, which advantageously makes it possible to compensate for inaccuracies in manufacturing. The second electrical contact can extend along the longitudinal direction along the grating. The second electrical contact can extend along the entire grating. Thus, each grating web can be supplied with electrical voltage, so that the absorption of the grating can be adjusted.

[0021] According to at least one embodiment of the semiconductor laser, at least one further grating comprising an electrochromic material is arranged next to the ridge region, wherein the further grating has a periodicity which is different from the periodicity of the grating. The further grating can have at least some of the properties of the grating. The further grating can have the same properties as the grating except for the spacing of the grating ridges and the periodicity. The periodicity refers to the spacing in the grating or further grating from which the structure repeats. For example, the periodicity is the distance from a first side of a grating ridge to the first side of an adjacent grating ridge. Grating ridges of the grating and grating ridges of the further grating can be arranged alternately.Because the additional grating has a different periodicity than the grating, electromagnetic radiation with a different wavelength than the grating experiences minimal absorption. Thus, the semiconductor laser can emit laser radiation with an additional main emission wavelength X during operation. w emit . For the distances a w the grid bars of the further grid then applies:

[0022] _ va w ~ 2 n

[0023] The further grating can have grating bars on two sides next to the bar region. This can mean that grating bars of the further grating are arranged on two sides next to the bar region along the lateral direction. The further grating can therefore have two regions with grating bars. These can be arranged on opposite sides of the bar region. The same number of grating bars of the further grating can be arranged on each of the two sides. The grating bars of the further grating can have the same shape on both sides. The grating bars of the further grating can be arranged in the same way on both sides. The semiconductor laser can have a plurality of further gratings, each with a different periodicity.

[0024] According to at least one embodiment of the semiconductor laser, the further grating is electrically connected to a further first electrical contact. The further grating can be in direct contact with the further first electrical contact. Each of the grating webs of the further grating can be electrically connected to the further first electrical contact. The further first electrical contact can be electrically insulated from the first electrical contact. The further first electrical contact can be arranged on opposite sides of the web region. This can mean that, if the further grating has two regions, the further first electrical contact is electrically connected to both regions. In this case, the further first electrical contact can also have two regions. The further first electrical contact can be connected to a further DC voltage source.The semiconductor laser can have the additional DC voltage source. It is also possible for the additional first electrical contact to be connected to the same DC voltage source as the first electrical contact. A DC voltage can be applied to the additional grating via the additional first electrical contact. This allows the absorption of the additional grating to be adjusted, which advantageously makes it possible to compensate for manufacturing inaccuracies. The manufacturing inaccuracies can be compensated for the additional grating in the same way as described for the grating.

[0025] According to at least one embodiment of the semiconductor laser, the grating and the additional grating each have grating webs that extend parallel to one another. This can mean that the grating has grating webs that extend parallel to the grating webs of the additional grating. Thus, the grating and the additional grating can be arranged compactly in the semiconductor laser.

[0026] According to at least one embodiment of the semiconductor laser, the grating and the further grating are electrically insulated from one another. For this purpose, an electrically insulating material can be arranged between the grating and the further grating. This allows the grating and the further grating to be controlled separately from one another. It is thus possible to select whether the laser emits laser radiation of the main emission wavelength or of the further

[0027] Main emission wavelength emitted .

[0028] According to at least one embodiment of the semiconductor laser, the grating comprises tungsten oxide or polyaniline. Both materials are electrochromic materials. This enables the advantages of the semiconductor laser described above.

[0029] According to at least one embodiment of the semiconductor laser, the ridge region has a smaller extension in a lateral direction than the substrate of the semiconductor laser, and the lateral direction runs parallel to the main extension plane of the active region. Thus, the ridge region can form a laser ridge.

[0030] Furthermore, a method for operating a semiconductor laser is specified. The semiconductor laser can preferably be operated using a method described here. In other words, all features disclosed for the semiconductor laser are also disclosed for the method for operating a semiconductor laser, and vice versa.

[0031] According to at least one embodiment of the method for operating a semiconductor laser, the method comprises a method step in which the semiconductor laser is provided with a grating arranged next to a ridge region.

[0032] According to at least one embodiment of the method for operating a semiconductor laser, the method comprises a method step in which the side mode suppression of a main emission wavelength of the semiconductor laser is determined. For this purpose, the intensity of the electromagnetic radiation emerging from the semiconductor laser during operation can be measured for a range of wavelengths. The intensity of the electromagnetic radiation emerging from the semiconductor laser during operation can be measured in a range around the main emission wavelength. The side mode suppression indicates how much lower the intensity of radiation with wavelengths is that are different from the main emission wavelength.To determine the side mode suppression, the intensity of the electromagnetic radiation emitted by the semiconductor laser can be measured for wavelengths of at least ± 50 nm or at least ± 100 nm around the main emission wavelength. The side mode suppression is given here in decibels (dB). This means that the side mode suppression is expressed as the logarithm of the ratio of the intensity of emitted radiation at the main emission wavelength to the intensity of emitted radiation at a different wavelength. The side mode suppression gives the smallest determined value for the ratio of the intensity of emitted radiation at the main emission wavelength to the intensity of emitted radiation at a different wavelength.This means that the side-mode suppression indicates the difference between the intensity of emitted radiation at the main emission wavelength and the intensity of the emitted radiation with the second-highest intensity. In other words, in a spectrum of emitted radiation, the side-mode suppression indicates the logarithm of the ratio of the highest measured intensity to the second-highest measured intensity. The side-mode suppression thus indicates how well the semiconductor laser suppresses side modes that are not the main emission wavelength.

[0033] According to at least one embodiment of the method for

[0034] Operating a semiconductor laser, the method comprises a method step in which, if the side mode suppression of the main emission wavelength is less than 40 dB, a DC voltage is applied to the grating. It is also possible to apply a DC voltage to the grating if the side mode suppression of the main emission wavelength is less than 30 dB, less than 20 dB or less than 10 dB. When operating the semiconductor laser with only one main emission wavelength, it may be desirable for the side mode suppression to be greater than 40 dB, 30 dB, 20 dB or greater than 10 dB. So that the semiconductor laser can meet this requirement, the side mode suppression is first determined. If this is too low, the optical properties of the grating can be changed by applying a DC voltage to the grating.This makes it possible to change the optical properties of the grating such that the side mode suppression is greater than 40 dB, than 30 dB, than 20 dB or greater than 10 dB.

[0035] According to at least one embodiment of the method for operating a semiconductor laser, the semiconductor laser has an active region which is designed to emit laser radiation during operation of the semiconductor laser (10).

[0036] According to at least one embodiment of the method for operating a semiconductor laser, the semiconductor laser has a ridge region which is arranged on the active region and comprises at least a part of the active region.

[0037] According to at least one embodiment of the method for operating a semiconductor laser, the grating comprises an electrochromic material. According to at least one embodiment of the method for operating a semiconductor laser, the method comprises providing the semiconductor laser with a grating arranged next to a ridge region, determining the side mode suppression of a main emission wavelength of the semiconductor laser, and, if the side mode suppression of the main emission wavelength is less than 40 dB, applying a DC voltage to the grating, wherein the semiconductor laser has an active region designed to emit laser radiation during operation of the semiconductor laser, the semiconductor laser has a ridge region which is arranged on the active region or comprises at least part of the active region, and the grating has an electrochromic material.

[0038] By applying a DC voltage to the grating, which comprises an electrochromic material, the optical properties of the grating can be changed, as described for the semiconductor laser, so that the side mode suppression can be increased. For operation with a single main emission wavelength, a side mode suppression of greater than 40 dB is typically desired.

[0039] According to at least one embodiment of the method for operating a semiconductor laser, the side mode suppression of the main emission wavelength is determined again after the DC voltage has been applied. This allows it to be determined whether the side mode suppression has reached a desired value due to the application of the DC voltage.

[0040] According to at least one embodiment of the method for

[0041] When operating a semiconductor laser, the applied DC voltage is changed until the side mode suppression of the main emission wavelength is greater than 40 dB. It is also possible to change the applied DC voltage until the side mode suppression of the main emission wavelength is greater than 30 dB, 20 dB, or 10 dB. The DC voltage can be applied throughout the entire operation of the semiconductor laser. It is also possible to apply the DC voltage only once to permanently change the optical properties of the grating. Whether the DC voltage is applied throughout the entire operation or only once depends on the material properties of the grating. In this way, the DC voltage can be chosen so that the side mode suppression reaches a desired value.

[0042] According to at least one embodiment of the method for operating a semiconductor laser, the applied DC voltage is changed until the side mode suppression of the main emission wavelength is less than 40 dB. By changing the applied DC voltage, the absorption of the grating for the main emission wavelength can be reduced. If the absorption of the main emission wavelength is very low, the semiconductor laser not only emits radiation of the main emission wavelength during operation, but standing waves of other wavelengths can also form in the resonator of the semiconductor laser, so that the laser can also emit laser radiation of other wavelengths. This can be desirable if the emission of a certain spectrum of laser radiation is desired. In this case, the side mode suppression of the main emission wavelength is less than 40 dB.The DC voltage applied to the grating can therefore be set such that the semiconductor laser emits laser radiation in a certain spectrum during operation. The semiconductor laser can therefore advantageously be used both to emit radiation with only one main emission wavelength and to emit radiation in a certain spectrum. To switch between these two options, only the voltage applied to the grating has to be changed. The switch between operation with only one main emission wavelength and operation with the emission of radiation in a certain spectrum can take place as quickly as required. In this way, an AC voltage can be applied to the grating. This means that two types of laser operation are possible with just one semiconductor laser.If the semiconductor laser has multiple gratings, even more than two types of laser operation may be possible, since the multi-grating semiconductor laser can emit laser radiation with different main emission wavelengths. This saves space in cases where different types of laser operation are required, since only one semiconductor laser is needed instead of two or more.

[0043] According to at least one embodiment of the method for operating a semiconductor laser, a further grating comprising an electrochromic material is arranged next to the ridge region, the further grating having a periodicity which is different from the periodicity of the grating, the side mode suppression of a further main emission wavelength of the semiconductor laser is determined, and in the event that the side mode suppression of the further main emission wavelength is less than 40 dB, a DC voltage is applied to the further grating. After the DC voltage has been applied, the side mode suppression of the further main emission wavelength can be determined again. In this way, it can be determined whether the side mode suppression of the further main emission wavelength has reached a desired value as a result of the application of the DC voltage.The applied DC voltage can be varied until the side mode suppression of the additional main emission wavelength is greater than 40 dB. As described for the grating, the additional grating can be used to compensate for inaccuracies in the manufacturing process by changing the optical properties of the additional grating.

[0044] In the following, the semiconductor laser described here and the method for operating a semiconductor laser described here are explained in more detail in conjunction with embodiments and the associated figures.

[0045] Figure 1 shows a semiconductor laser according to an embodiment.

[0046] Figure 2 shows a cross section through a semiconductor laser according to an embodiment.

[0047] Figures 3, 4 and 5 show further embodiments of the semiconductor laser.

[0048] Figure 6 shows a plan view of a grid and another grid .

[0049] Figure 7 describes an exemplary embodiment of the method for operating a semiconductor laser. Figures 8 and 9 show further exemplary embodiments of the semiconductor laser.

[0050] Identical, similar, or functionally identical elements are provided with the same reference symbols in the figures. The figures and the relative sizes of the elements depicted in the figures are not to scale. Rather, individual elements may be exaggerated for clarity and / or clarity.

[0051] Figure 1 shows a semiconductor laser 10 according to an exemplary embodiment. The semiconductor laser 10 comprises a substrate 23 on which a cladding layer 24 is arranged. The substrate 23 can comprise GaN, GaAs, InP, GaSb, Si or sapphire, for example. The cladding layer 24 is doped with a second dopant. A second region 12 is arranged on the cladding layer 24. The second region 12 is doped with the second dopant. The second region 12 can have a higher dopant concentration than the cladding layer 24. A lower electrical contact 25 is arranged on the side of the substrate 23 facing away from the cladding layer 24. An active region 13 is arranged on the second region 12 and is designed to emit laser radiation during operation of the semiconductor laser 10. A first region 11 is arranged on the active region 13. The active region 13 is doped with a first dopant.A ridge region 14 is arranged on the first region 11. The ridge region 14 is doped with the first dopant. The ridge region 14 has a smaller extent in a lateral direction x onto the substrate 23 of the semiconductor laser 10, wherein the lateral direction x runs parallel to the main extension plane of the active region 13. The ridge region 14 extends along a longitudinal direction y, which also runs parallel to the main extension plane of the first region 11. The longitudinal direction y extends perpendicular to the lateral direction x. The ridge region 14 can be arranged centrally on the first region 11 along the lateral direction x.

[0052] A grating 15 is arranged on the first region 11 and adjacent to the web region 14. The grating 15 comprises an electrochromic material. The grating 15 can comprise tungsten oxide or polyaniline. The grating 15 has a plurality of grating webs 22 on two sides of the web region 14.

[0053] A passivation layer 26 is arranged on the grid 15 and on the first region 11. The passivation layer

[0054] 26 completely covers the grid 15 and the first region 11. On the web region 14 and the passivation layer 26, an upper electrical contact

[0055] 27 . The upper electrical contact 27 completely covers the ridge region 14 and partially covers the passivation layer 26 . The upper electrical contact 27 and the lower electrical contact 25 can comprise gold. Below the ridge region 14 and around the active region 13, the electromagnetic radiation emitted by the semiconductor laser 10 during operation is schematically illustrated.

[0056] Figure 2 shows a cross-section through a portion of the semiconductor laser 10 according to one exemplary embodiment. The cross-section shows the first region 11, the active region 13, and the second region 12. Two grating webs 22 of the grating 15 are also shown. Lines schematically show the extent of the light field, i.e., the electromagnetic radiation generated by the semiconductor laser 10. It can be seen that the light field slightly overlaps the grating 15.

[0057] Figure 3 shows a further exemplary embodiment of the semiconductor laser 10. In contrast to the exemplary embodiment shown in Figure 1, the semiconductor laser 10 has a first electrical contact 16 and a second electrical contact 18. The grating 15 is electrically connected to the first electrical contact 16. For this purpose, the first electrical contact 16 is arranged on the grating 15. The first electrical contact 16 extends along the longitudinal direction y along the grating 15 and completely covers the grating 15 and the first region 11. The passivation layer 26 is arranged on the first electrical contact 16. The first electrical contact 16 is connected to a DC voltage source 17.

[0058] The second electrical contact 18 is arranged on a bottom side 19 of the semiconductor laser 10. The second electrical contact 18 extends parallel to the first electrical contact 16 and is in direct contact with the lower electrical contact 25. The second electrical contact 18 is also connected to the DC voltage source 17. It is also possible for the lower electrical contact 25 to be connected directly to the DC voltage source 17.

[0059] For clarity, Figure 3 only shows the first electrical contact 16 and the second electrical contact 18 for one side of the grid 15, namely the right side. On the other side, the left side, the first electrical contact 16 and the second electrical contact 18 can be arranged in a mirror-inverted manner, as shown for the right side.

[0060] Figure 4 shows a further exemplary embodiment of the semiconductor laser 10. In contrast to the exemplary embodiment shown in Figure 3, the second electrical contact 18 is not arranged on the underside 19 of the semiconductor laser 10 but rather on the first region 11. The second electrical contact 18 is in electrical contact with the grating 15. The second electrical contact 18 extends parallel to the first electrical contact 16. The passivation layer 26 is arranged between the first electrical contact 16 and the second electrical contact 18.

[0061] As in Figure 3, in Figure 4 only the first electrical contact 16 and the second electrical contact 18 are shown for one side of the grid 15, namely the right side. On the other side, the left side, the first electrical contact 16 and the second electrical contact 18 can be arranged in a mirror-inverted manner as shown for the right side.

[0062] Figure 5 shows a further embodiment of the semiconductor laser 10. In contrast to the embodiment shown in Figure 4, the semiconductor laser 10 additionally has a further grating 20. The further grating 20 is arranged on the first region 11 and next to the ridge region 14. The further grating 20 has an electrochromic material. The further grating 20 has a periodicity which is different from the periodicity of the grating 15. This is shown in more detail in Figure 6. The grating ridges 22 of the grating 15 and the further grating 20 are arranged next to one another and alternately along the longitudinal direction y. Thus, the grating 15 and the further grating 20 each have

[0063] Grid webs 22 which extend parallel to one another.

[0064] The further grid 20 is electrically connected to a further first electrical contact 21. The further first electrical contact 21 has a plurality of components, each of which is in direct contact with one of the grid webs 22 of the further grid 20. The components of the further first electrical contact 21 are all electrically connected to one another and to the DC voltage source 17. Likewise, the first electrical contact 16 has a plurality of components, each of which is in direct contact with one of the grid webs 22 of the grid 15. The components of the first electrical contact 16 are all electrically connected to one another and to the DC voltage source 17. The first electrical contact 16 and the further first contact 21 are arranged on the passivation layer 26. The grid 15 and the further grid 20 are electrically insulated from one another.The second electrical contact 18 is arranged between the grid 15 and the further grid 20 on the one hand and the first region 11 on the other hand.

[0065] Figure 6 shows a plan view of a grating 15 and a further grating 20 according to an exemplary embodiment of the semiconductor laser 10. The ridge region 14 is arranged in the center. Grating ridges 22 of the grating 15 and the further grating 20 are arranged alternately on both sides of the ridge region 14. Since the periodicity of the further grating 20 is different from the periodicity of the grating 15, the distances between the grating ridges 22 change along the longitudinal direction y. The difference in periodicity is exaggerated here and can be smaller. Figure 7 describes an exemplary embodiment of the method for operating the semiconductor laser 10. In a first step S1 of the method, the semiconductor laser 10 is provided. In a second step S2 of the method, the side mode suppression of a main emission wavelength of the semiconductor laser 10 is determined.In a third step of the method, in the event that the side mode suppression of the main emission wavelength is less than 20 dB, a DC voltage is applied to the grating 15. In a fourth step S4 of the method, after the DC voltage has been applied, the side mode suppression of the main emission wavelength is determined again. In a fifth step S5 of the method, the applied DC voltage is changed until the side mode suppression of the main emission wavelength is greater than 20 dB. Alternatively, in the fifth step S5, the applied DC voltage can be changed until the side mode suppression of the main emission wavelength is less than 20 dB.

[0066] If the semiconductor laser 10 has a further grating 20, the side mode suppression of a further main emission wavelength of the semiconductor laser 10 can be determined in a further step of the method, and in the event that the side mode suppression of the further main emission wavelength is less than 20 dB, a DC voltage can be applied to the further grating 20.

[0067] Figure 8 shows a cross-section through another exemplary embodiment of the semiconductor laser 10. In contrast to the exemplary embodiment of Figure 1, the ridge region 14 comprises the active region 13 and the first region 11. The upper electrical contact 27 is arranged on the ridge region 14. The two circles mark the overlap of the light field with the grating 15.

[0068] Figure 9 shows a cross-section through another exemplary embodiment of the semiconductor laser 10. In contrast to the exemplary embodiment of Figure 1, the ridge region 14 comprises a portion of the active region 13 and the first region 11. The upper electrical contact 27 is arranged on the ridge region 14. The two circles mark the overlap of the light field with the grating 15.

[0069] The features and exemplary embodiments described in conjunction with the figures can be combined with one another according to further exemplary embodiments, even if not all combinations are explicitly described. Furthermore, the exemplary embodiments described in conjunction with the figures can alternatively or additionally comprise further features according to the description in the general part.

[0070] The invention is not limited to the embodiments described herein. Rather, the invention encompasses any novel feature and any combination of features, including, in particular, any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the claims or embodiments.

[0071] This patent application claims priority from German patent application 10 2024 109 702 . 7 , the contents of which are hereby incorporated by reference. List of reference symbols

[0072] 10 semiconductor lasers

[0073] 11 first area

[0074] 12 second area

[0075] 13 active area

[0076] 14 Bridge area

[0077] 15 grids

[0078] 16 first electrical contact

[0079] 17 DC voltage source

[0080] 18 second electrical contact

[0081] 19 Bottom

[0082] 20 additional grids

[0083] 21 further first electrical contact

[0084] 22 Lattice bridge

[0085] 23 Substrat

[0086] 24 sheath layer

[0087] 25 lower electrical contact

[0088] 26 Passivation layer

[0089] 27 upper electrical contact

[0090] S 1 to S5 steps x lateral direction y longitudinal direction

Claims

Patent claims 1. Semiconductor laser (10) comprising: - an active region (13) which is designed to emit laser radiation during operation of the semiconductor laser (10), - a web area (14) which is located on the active area (13) is arranged or comprises at least part of the active region (13), and - a grid (15) arranged next to the web area (14), wherein - the grid (15) comprises an electrochromic material.

2. Semiconductor laser (10) according to the preceding claim, wherein the grating (15) is electrically connected to a first electrical contact (16).

3. Semiconductor laser (10) according to the preceding claim, wherein the first electrical contact (16) is connected to a DC voltage source (17).

4. Semiconductor laser (10) according to one of claims 2 or 3, wherein the first electrical contact (16) on the grating (15) is arranged.

5. Semiconductor laser (10) according to one of claims 2 to 4, wherein the first electrical contact (16) extends along a longitudinal direction (y) along the grating (15) and the longitudinal direction (y) runs parallel to the main extension plane of the active region (13).

6. Semiconductor laser (10) according to one of the preceding claims, wherein a second electrical contact (18) is arranged on an underside (19) of the semiconductor laser (10).

7. Semiconductor laser (10) according to one of claims 1 to 5, wherein a second electrical contact (18) is in electrical contact with the grating (15).

8. Semiconductor laser (10) according to one of the preceding claims, in which a further grating (20) comprising an electrochromic material is arranged next to the ridge region (14), wherein the further grating (20) has a periodicity which is different from the periodicity of the grating (15).

9. Semiconductor laser (10) according to the preceding claim, wherein the further grating (20) is electrically connected to a further first electrical contact (21).

10. Semiconductor laser (10) according to one of claims 8 or 9, wherein the grating (15) and the further grating (20) each have grating webs (22) which extend parallel to one another.

11. Semiconductor laser (10) according to one of claims 8 to 10, wherein the grating (15) and the further grating (20) are electrically insulated from each other.

12. Semiconductor laser (10) according to one of the preceding claims, wherein the grating (15) comprises tungsten oxide or polyaniline.

13. Semiconductor laser (10) according to one of the preceding Claims, in which the web region (14) in a lateral direction (x) has a smaller extension than a Substrate (23) of the semiconductor laser (10) and the lateral direction (x) parallel to the main extension plane of the active area (13).

14. A method for operating a semiconductor laser (10), the method comprising: - providing the semiconductor laser (10) with a grating (15) arranged next to a ridge region (14), - determining the side mode suppression of a main emission wavelength of the semiconductor laser (10), and - in the event that the side mode suppression of the main emission wavelength is less than 40 dB, applying a DC voltage to the grating (15), wherein - the semiconductor laser (10) has an active region (13) which is designed to emit laser radiation during operation of the semiconductor laser (10), - the semiconductor laser (10) has a ridge region (14) which is arranged on the active region (13) or comprises at least a part of the active region (13), and - the grid (15) comprises an electrochromic material.

15. Method according to claim 14, wherein after applying the DC voltage is used to determine the side mode suppression of the main emission wavelength again.

16. A method according to claim 15, wherein the applied DC voltage is changed until the Side mode suppression of the main emission wavelength is greater than 40 dB.

17. The method according to claim 15, wherein the applied DC voltage is changed until the Side mode suppression of the main emission wavelength is less than 40 dB.

18. Method according to one of claims 14 to 17, wherein next to the web region (14) a further grid (20) is arranged, which comprises an electrochromic material, wherein - the further grating (20) has a periodicity which is different from the periodicity of the grating (15), - the side mode suppression of a further Main emission wavelength of the semiconductor laser (10) is determined, and - in the event that the side mode suppression of the further main emission wavelength is less than 40 dB, a DC voltage is applied to the further grating (20).

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