阅读说明：本技术 用于产生激光辐射的装置 (Device for generating laser radiation ) 是由 埃尔伯特·格茨 温泽尔·汉斯 克尼格·史蒂芬 马丁·克里斯蒂安·多米尼克 马斯多夫·安德烈 于 2020-01-09 设计创作，主要内容包括：本发明涉及一种用于产生激光辐射的装置。本发明的目的是提供一种同时具有高效率和低远场发散度的激光二极管。根据本发明的二极管激光器包括电流阻挡层(5),其特征在于,所述电流阻挡层(5)沿第三轴线(X)延伸,其中所述电流阻挡层(5)具有至少一个开口,并且所述电流阻挡层(5)的所述开口沿所述第三轴线(X)的第一宽度(W1)小于所述金属p触头(8)沿所述第三轴线(X)的第二宽度(W2)。(The invention relates to a device for generating laser radiation. It is an object of the present invention to provide a laser diode having both high efficiency and low far field divergence. The diode laser according to the invention comprises a current blocking layer (5), characterized in that the current blocking layer (5) extends along a third axis (X), wherein the current blocking layer (5) has at least one opening, and a first width (W1) of the opening of the current blocking layer (5) along the third axis (X) is smaller than a second width (W2) of the metal p-contact (8) along the third axis (X).)

1. A diode laser having:

a) a first n-type functional layer (2),

b) a metal n-contact (1),

c) an active layer (3) adapted to generate electromagnetic radiation and arranged on the first functional layer (2),

d) a second p-type functional layer (4, 7) arranged on the active layer (3), wherein the second functional layer (4, 7) comprises a first p-type layer (4) and a second p-type layer (7),

e) a metal p-contact (8),

f) a current blocking layer (5), the current blocking layer (5) being arranged between the first p-type layer (4) and the second p-type layer (7),

g) at least one facet for coupling out electromagnetic radiation along a first axis (Z), wherein the first functional layer (2), the active layer (10) and the second functional layer (4, 7) are stacked along a second axis (Y), wherein

h) The current blocking layer (5) extends along a third axis (X), wherein

i) The current blocking layer (5) has at least one opening, and wherein

j) A first width (W1) of the opening of the current blocking layer (5) along the third axis (X) is smaller than a second width (W2) of the metal p-contact (8) along the third axis (X),

it is characterized in that the preparation method is characterized in that,

k) the thickness of the current blocking layer (5) is more than 0.25 mu m.

2. The diode laser of claim 1, wherein the current blocking layer is introduced only in a partial region of the first p-type layer.

3. A diode laser according to any of the preceding claims, wherein the first n-type functional layer (2) consists of exactly one n-cladding layer, one n-waveguide layer and one n-contact layer.

4. A diode laser according to any of the preceding claims, wherein the first p-type layer (4) consists of exactly one p-waveguide layer and one p-cladding layer.

5. A diode laser as claimed in any preceding claim, wherein the second p-type layer consists of exactly one p-contact layer.

6. The diode laser according to any of the preceding claims, wherein the specific resistance of the current blocking layer (5) is more than twice the amount of the specific resistance of the layer structure used.

7. The diode laser according to any of the preceding claims, wherein the first p-type layer (4) and the second p-type layer (7) are composed of different materials.

8. The diode laser according to any of the preceding claims, wherein the thickness (h3) of the first p-type layer (4) is smaller than the thickness (h2) of the second p-type layer (7).

9. The diode laser according to any of the preceding claims, wherein the current blocking layer (5) has a plurality of openings, wherein a projection of the openings along the second axis (Y) completely overlaps the metal p-contact (8).

10. The diode laser according to any of the preceding claims, wherein at least two active layers (3a, 3b) are arranged at a distance from each other along the second axis (Y), and wherein at least two current blocking layers (5a, 5b) are provided, which are arranged at a distance from each other along the second axis (Y).

11. The diode laser according to any of claims 1 to 9, wherein at least two active layers (3a, 3b) are arranged at a distance from each other along the second axis (Y), and wherein only one current blocking layer (5a) is provided.

12. The diode laser according to any of the preceding claims, wherein at least two current blocking layers (5) are provided, which are arranged at a distance from each other along the first axis (Z).

13. The diode laser according to any of the preceding claims, wherein the width (W1r, W1f) of the opening of the current blocking layer (5) varies along the first axis (Z).

14. A method for producing a diode laser, having the following method steps:

a) a first n-type functional layer (2) is arranged,

b) an active layer (3) configured to generate electromagnetic radiation and arranged on the first functional layer (2),

c) a first p-type layer (4) arranged on the active layer (3),

d) introducing foreign atoms into the first p-type layer (4) in order to configure a current blocking layer (5),

e) subsequently arranging a second p-type layer (7) on said first p-type layer (4),

f) a metal n-contact (1) arranged below the first n-type functional layer (2) and a metal p-contact (8) arranged above the second p-type layer (7), wherein

g) The foreign atoms are introduced only into partial regions of the first p-type layer (4), wherein

h) The width (W1) of the partial region of the first p-type layer (4) in which no foreign atoms are introduced is smaller than the width (W2) of the metal p-contact (8),

it is characterized in that the preparation method is characterized in that,

the thickness of the current blocking layer (5) is configured to be greater than 0.25 μm.

15. The method of claim 14, wherein the foreign atoms are introduced by means of a structured mask.

16. The method of claim 15, wherein said mask is arranged on said first p-type layer (4) before introducing said foreign atoms and said mask is removed again after introducing said foreign atoms into said first p-type layer (4).

17. The method of any of claims 14 to 16, wherein silicon, oxygen, iron or selenium is introduced as foreign atoms into the first p-type layer (4).

18. The method of any of claims 14 to 17, wherein the first n-type functional layer (2), the active layer (3), the first p-type layer (4) and the second p-type layer are configured by means of an epitaxial process.

19. The method according to any of claims 14 to 18, wherein a thickness (h3) of the first p-type layer (4) is configured to be smaller than a thickness (h2) of the second p-type layer (7).

20. A method according to any one of claims 14 to 19, wherein a diode laser according to any one of claims 1 to 13 is produced.

Technical Field

The invention relates to a device for generating laser radiation.

Background

In general, an edge-emitting laser diode (diode laser) has an active layer embedded in semiconductor layers that differ from each other due to their band gap, refractive index, and doping. The layers below and above the active layer differ in particular by the conductivity type (n or p). In addition to ensuring transport of electrons and holes to the active layer, where they recombine in an excited manner and produce laser radiation, these layers also serve to direct the laser light vertically. The layer adjacent to the active layer is referred to as a waveguide layer, and the layer adjacent to the waveguide layer is referred to as a cladding layer. Generally, the refractive index of the active layer is greater than that of the waveguide layer, which is greater than that of the cladding layer [ E.kapon (eds.) "Semiconductor Lasers I: Fundamentals", Academic Press 1998 ]. However, other configurations are also possible (e.g., Vertical ARROW [ H.Wenzel et al: "High-power diode lasers with small Vertical beam diode emitting at 808 nm", Electronics Letters, Vol.37, (2001) ], photonic band crystals [ M.V.Maximum et al: "Longitudinal photonic band crystal diodes with ultra-narrow Vertical beam diode emitting", Proc.SPIE, Vol.6115, (2006) ]).

The epitaxially grown semiconductor layer structure of the edge-emitting diode laser is electrically contacted by a large-area metal n-contact and a defined metal p-contact. A voltage is applied between the two contacts in a manner that causes a current to flow between the two contacts, thereby injecting holes and electrons into the active layer. The width of the n-contact is typically the same as the width of the laser chip. The size of the p-contact is selected according to the desired emission aperture. The electrically pumped surface is always wider than the p-contact due to the lateral widening of the current path between the p-contact and the active layer. The so-called current path widening occurs first and foremost in the heavily doped contact layer, but also in the underlying p-doped layer.

DE102008014093a1 discloses a laser diode which is suitable for generating laser radiation with reduced beam divergence.

Disadvantageously, however, high electrical resistance and low thermal conductivity result from the narrow p-contact. In addition, due to the relatively narrow p-contact layer, crystal defects may be generated by mechanical tension applied from the outside.

Disclosure of Invention

It is therefore an object of the present invention to achieve low resistance of the p-contact despite low beam divergence.

According to the invention, these objects are achieved by the features of claim 1 (device) and claim 12 (method). Advantageous embodiments of the invention are contained in the dependent claims.

The diode laser according to the present invention comprises: a first n-type functional layer; a metal n-contact; an active layer adapted to generate electromagnetic radiation and arranged on the first functional layer; a second p-type functional layer disposed on the active layer, wherein the second functional layer comprises a first p-type layer and a second p-type layer; a metal p-contact; a current blocking layer disposed between the first p-type layer and the second p-type layer; at least one facet for coupling out electromagnetic radiation along a first axis, wherein the first functional layer, the active layer and the second functional layer are stacked along a second axis, wherein the current blocking layer extends along a third axis, wherein the current blocking layer has at least one opening, and a first width of the opening along the third axis is smaller than a second width of the metal p-contact along the third axis.

The idea of the invention is to introduce a current blocking layer into the diode laser such that the size of the contact surface of the metal p-contact and the thickness of the second p-type layer located below the metal p-contact can be increased. This has the advantage that a larger p-contact surface can significantly reduce the resistance without negatively affecting the beam characteristics, and a thicker second p-type layer can allow for easier relief of mechanical strain, which has a positive effect on the lifetime and beam quality of the laser.

The current blocking layer is preferably introduced only in partial regions of the first p-type layer.

The first n-type functional layer preferably comprises an n-cladding layer, an n-waveguide layer and an n-contact layer, even more preferably the first n-type functional layer consists of exactly one n-cladding layer, one n-waveguide layer and one n-contact layer.

The first p-type layer preferably comprises a p-waveguide layer and a p-cladding layer, even more preferably the first p-type layer consists of exactly one p-waveguide layer and one p-cladding layer.

The second p-type layer preferably comprises a p-contact layer, even more preferably the second p-type layer consists of exactly one p-contact layer.

The thickness of the first p-type layer is preferably less than the thickness of the second p-type layer. This is advantageous because the mechanical tension of the semiconductor layer can thus be relieved.

In a preferred embodiment, the projection of the opening of the current blocking layer along the second axis completely overlaps the metal p-contact. This has the advantage that the current spreading is reduced and thus the laser becomes more efficient.

According to a further embodiment of the invention, the current blocking layer has a plurality of openings, wherein a projection of the openings along the second axis completely overlaps the metal p-contact. This is advantageous because the shaping of the optical laser beam field and thus the improvement of the beam quality can be achieved by modulating the current density and thus the injected charge carriers in the active layer.

All openings in the current blocking layer are preferably of equal width. This prevents non-uniformity of current density in the active layer, resulting in additional advantages in beam quality.

A uniform distribution of the openings of the current blocking layer along the transverse (third) axis is further preferred. This ensures that the active area is utilized as completely as possible.

In a further embodiment according to the present invention, preferably at least two active layers are provided, which are arranged at a distance from each other along the second axis, and wherein at least two current blocking layers are provided (that is to say for the at least two active layers, at least two current blocking layers at a distance from each other along the second axis). This makes it possible to combine the advantages of diode lasers for both frequencies or diode lasers with twice the output power at the same current with the advantages of current blocking layers. In this case, two emitters are stacked.

In a further embodiment according to the present invention, preferably at least two active layers are provided, which are arranged at a distance from each other along the second axis, wherein only one current blocking layer is provided. This embodiment has the advantage of simpler production, since only one current blocking layer has to be provided.

According to a further embodiment of the invention, at least two current blocking layers are provided, which are at a distance from each other along the first axis. Therefore, the active region is further utilized as completely as possible, and the beam characteristics of the laser are improved.

In an embodiment according to the invention, the width of the opening of the current blocking layer varies along the first axis. Here, the laser beam characteristic may be changed via the first axis.

According to a further embodiment, a current blocking layer is provided along the first axis in the area of the facets.

The difference between the second width of the metal p-contact and the first width of the opening of the current blocking layer is preferably larger than 1 μm, even more preferably larger than 5 μm, even more preferably larger than 20 μm, even more preferably larger than 50 μm. As the difference between the second width of the metal p-contact and the first width of the opening of the current blocking layer increases, a lower resistance is achieved due to the wider metal p-contact and heat dissipation becomes more efficient, wherein at the same time current spreading is prevented.

The first width of the opening of the current blocking layer is preferably larger than 0.5 μm, more preferably larger than 2 μm, more preferably larger than 5 μm, more preferably larger than 10 μm, more preferably larger than 30 μm, more preferably larger than 50 μm, more preferably larger than 100 μm, more preferably larger than 200 μm and even more preferably larger than 400 μm. Due to the larger opening in the current blocking layer, the current is more efficiently conducted through the blocking layer, but does not accept current spreading.

The thickness of the current blocking layer is preferably larger than 0.10 μm, more preferably larger than 0.15 μm, even more preferably larger than 0.20 μm, even more preferably larger than 0.25 μm, even more preferably larger than 0.30 μm, even more preferably larger than 0.40 μm, even more preferably larger than 0.50 μm and even more preferably larger than 1.00 μm. The conductivity becomes more resistant due to the thicker current blocking layer.

The distance of the current blocking layer from the active layer is preferably less than 1 μm, more preferably less than 0.5 μm, more preferably less than 0.2 μm, more preferably less than 0.1 μm, even more preferably less than 0.01 μm. The current spreading can be better prevented by the smaller distance of the current blocking layer from the active layer.

The thickness of the first p-type layer is preferably less than 5 μm, more preferably less than 2 μm, more preferably less than 1 μm, more preferably less than 0.5 μm, more preferably less than 0.2 μm and even more preferably less than 0.1 μm. The introduction of the current blocking layer can be facilitated by a smaller layer thickness of the first p-type layer.

The thickness of the second p-type layer is preferably larger than 0.05 μm, more preferably larger than 0.1 μm, more preferably larger than 0.5 μm, more preferably larger than 1 μm, even more preferably larger than 5 μm. Due to the larger layer thickness of the second p-type layer, the mechanical stress resulting in crystal defects can be better mitigated.

The quotient of the thickness of the second p-type layer and the thickness of the first p-type layer is preferably greater than 0.1, more preferably greater than 0.2, more preferably greater than 1, more preferably greater than 2, even more preferably greater than 10. This results in the advantage that the current spreading is minimized after the current has passed through the current blocking layer.

The diode laser is preferably configured as an edge emitting diode laser. The diode laser is preferably configured as an optical amplifier. This results in the advantage that the laser diode can be constructed as easily as possible.

A carrier substrate (for example, GaAs, InP, GaSb or GaN) is preferably provided, on which the layer structure shown is formed.

The first n-type functional layer is preferably arranged on the side of the active layer facing the carrier substrate, while the second p-type functional layer is arranged on the side of the active layer facing away from the carrier substrate.

The metal n-contact is preferably arranged on the side of the carrier substrate facing away from the first n-type functional layer.

The current blocking layer preferably has a specific resistance (hereinafter referred to as σ) which is significantly greater than the layer structure used_cExample σ_c＝5.5×10^-5Ω-cm²) The specific resistance of (2). The specific resistance of the resistive element is preferably larger than 2 sigma_c(e.g., 1.1X 10)^-4Ω-cm²) Further preferably greater than 10 sigma_c(e.g., 5.5X 10)^-4Ω-cm²) Further preferably greater than 10²σ_c(e.g., 5.5X 10)^-3Ω-cm²) Further preferably greater than 10³σ_c(e.g., 5.5X 10)^-2Ω-cm²) Further preferably greater than 10⁴σ_c(e.g., 5.5X 10)^-1Ω-cm²) Further preferably greater than 10⁵σ_c(e.g., 5.5. omega. -cm)²) Further preferably greater than 10⁶σ_c(e.g., 5.5X 10)¹Ω-cm²) Further preferably greater than 10⁷σ_c(e.g., 5.5X 10)²Ω-cm²) Further preferably greater than 10⁸σ_c(e.g., 5.5X 10)³Ω-cm²) And particularly preferably greater than 10⁹σ_c(e.g., 5.5X 10)⁴Ω-cm²)。

In a further preferred embodiment, the ratio of the specific resistance of the current blocking layer to the specific resistance of the layer structure used is greater than 2, further preferably greater than 10²Further preferably greater than 10³Further preferably greater than 10⁴Further preferably greater than 10⁵Further preferably greater than 10⁶Further preferably greater than 10⁷Further preferably greater than 10⁸And particularly preferably greater than 10⁹。

The first p-type layer and the second p-type layer are preferably composed of different materials.

Further preferably, the current blocking layer and the first p-type layer consist of the same substrate, wherein the current blocking layer is configured to be doped with foreign atoms.

Another aspect of the invention relates to a method for producing a laser diode.

The indicated method for producing a laser diode comprises the following method steps: the method comprises the steps of providing a first n-type functional layer, providing an active layer adapted to generate electromagnetic radiation and arranged on the first functional layer, providing a first p-type layer on the active layer, introducing foreign atoms into the first p-type layer in order to provide a current blocking layer, subsequently providing a second p-type layer on the first p-type layer, providing a metal n-contact under the first n-type functional layer and providing a metal p-contact on the second p-type layer, wherein the foreign atoms are introduced only into a partial region of the first p-type layer, wherein the width of the partial region of the first p-type layer where no foreign atoms are introduced is smaller than the width of the metal p-contact.

In a preferred embodiment, the foreign atoms are introduced by means of a structured mask, which is more preferably arranged on the first p-type layer before the introduction of the foreign atoms and is removed again after the introduction of the foreign atoms into the first p-type layer. This makes it easy to introduce foreign atoms into the first p-type layer by, for example, implantation or diffusion.

Silicon, oxygen, iron or selenium is preferably introduced as foreign atoms into the first p-type layer in order to configure the current blocking layer. This results in a long-term stable and resistant current blocking layer.

The first n-type functional layer, the active layer, the first p-type layer and the second p-type layer are preferably configured by means of an epitaxial process.

In the method, the thickness of the first p-type layer is preferably configured to be smaller than the thickness of the second p-type layer.

In the method, the thickness of the current blocking layer is preferably configured to be greater than 0.10 μm, more preferably greater than 0.15 μm, even more preferably greater than 0.20 μm, even more preferably greater than 0.25 μm, even more preferably greater than 0.30 μm, even more preferably greater than 0.40 μm, even more preferably greater than 0.50 μm and even more preferably greater than 1.00 μm. The conductivity becomes more resistant due to the thicker current blocking layer.

Wider metal p-contacts reduce the resistance, resulting in more efficient operation of the laser. The heat dissipation during p-bottom mounting of the laser is additionally improved by the larger contact surface. The thicker second p-type layer increases the distance from the metal p-contact to the active layer and thus allows for greater tolerance for facet coating and p-bottom mounting. The mechanical strain introduced by the mounting in the semiconductor layer is better mitigated by the thicker second p-type layer, with the result that fewer crystal defects are generated near the active layer, which improves the lifetime. The thicker second p-type layer also has a positive effect on the degree of polarization and the form of the thermal lens and thus on the beam quality.

The various implementations and aspects of the invention indicated in the present application may be advantageously combined with each other, unless otherwise indicated in individual cases. In particular, representations and descriptions of preferred configurations and embodiments of the method can accordingly be transferred continuously to the apparatus and vice versa.

Drawings

The invention is explained below in exemplary embodiments with reference to the associated drawings, in which:

figure 1 shows a laser diode according to the invention in a schematic cross-sectional view,

figure 2 shows in a schematic cross-sectional view another laser diode according to the invention,

figure 3A shows in a schematic cross-sectional view a further laser diode according to the invention,

figure 3B shows in a schematic cross-sectional view a further laser diode according to the invention,

figure 4 shows a schematic representation of a top view of the laser diode from figure 1 according to the invention,

figure 5 shows a schematic representation of a top view of the laser diode from figure 2 according to the invention,

figure 6 shows a schematic representation of a top view of a variant of the laser diode from figure 1 according to the invention,

FIG. 7 shows a schematic representation of a top view of a further variant of the laser diode from FIG. 1 according to the invention, and

fig. 8 shows a schematic representation of a top view of a further variant of the laser diode from fig. 1 according to the invention.

Detailed Description

Fig. 1 shows a first embodiment of a laser diode according to the invention in a schematic cross-sectional view. The laser diode has a layer structure with a metallic n-type contact 1, a first n-type functional layer 2 (comprising an n-type carrier substrate) arranged on the metallic n-type contact, an active layer 3 arranged on the first n-type functional layer, a first p-type layer 4 arranged on the active layer, a current blocking layer 5, a second p-type layer 7 arranged on the current blocking layer 5 and a metallic p-type contact 8 arranged on the second p-type layer 7, wherein a boundary surface 6 is arranged between the first p-type layer 4 and the second p-type layer 7. In the embodiment of fig. 1, the current blocking layer 5 is configured as a foreign atom-implanted portion of the first p-type layer 4, wherein the non-implanted portion of the first p-type layer 4 is configured to have a first thickness h1, the current blocking layer 5 is configured to have a thickness d1, and the second p-type layer 7 is configured to have a second thickness h 2. The current blocking layer 5 is configured with an opening having a first width W1, and the metal p-contact is configured with a second width W2. The width of the metal n-contact is configured to correspond to the third width W3 of the laser diode chip. In this embodiment, the current path is limited by the current blocking layer 5 having an opening. Current flows from the metal p-contact 8 through the opening of the current blocking layer 5 in the direction of the active layer 3. The current blocking layer 5 counteracts the spreading of the current. This ensures that a wide p-contact 8 can be utilized. Since the current spreading is counteracted, the second p-type layers 7 can also spread over their layer thickness without adversely affecting the current spreading.

In a preferred exemplary embodiment for generating laser radiation having a wavelength of 920nm, the active layer 3 is preferably composed of In, for example_yGa_1-yAs configuration with a thickness of 7nm and an In molar proportion y of 10%. The first n-type functional layer 2, the first p-type layer 4, the current blocking layer 5 and the second p-type layer 7 are made of Al_xGa_1-xAs is produced. The first n-type functional layer 2 is preferably made of Al in Al_xGa_1-xAn n-cladding layer with a molar ratio x of 35% in As and a layer thickness of 1.5 μm, an n-waveguide layer with a layer thickness of 2.5 μm, wherein the molar ratio of Al of 35% at the boundary with the n-cladding layer drops to 20% at the lower boundary with the active layer 3. The first p-type layer 4 with layer thickness h3 consists of a p-type waveguide layer with a layer thickness of 0.25 μm (with an increase in the molar proportion of 20% of Al to 70% at the boundary with the active layer 3) and an adjoining p-cladding layer with a layer thickness of 0.6 μm and a molar proportion of 70% of Al. The molar proportion of Al in the second p-type layer 7 having a thickness h2 of 1 μm was 0%.

Fig. 2 shows a further embodiment of a laser diode according to the invention in a schematic cross-sectional view. In this embodiment, as an example, the current blocking layer 5 is configured to have four openings having widths W11, W12, W13, and W14. This achieves a modulation of the current density and thus of the charge carriers injected in the active layer along the third axis X, as a result of which the optical laser beam field is shaped and an improvement in the beam quality can be achieved. In a preferred embodiment, the widths W11, W12, W13 and W14 of the openings of the current shield have the same dimensions, as a result of which a particularly uniform power distribution along the second axis Y is achieved.

Fig. 3A shows a further embodiment of a laser diode according to the invention in a schematic cross-sectional view. In this embodiment, the laser diode is provided with two stacked emitters a, b along the second axis Y, wherein a current blocking layer 5a, 5b is provided for each emitter. The two emitters are preferably separated from each other by a tunnel diode 10. In this embodiment, by constantly using the current blocking layers 5a, 5b to counteract the spread of the current, twice the light output can be produced by the contacts 1, 8 at the same current.

Fig. 3B shows a further embodiment of a laser diode according to the invention in a schematic cross-sectional view. In this embodiment of the laser diode with two emitters a, b stacked along the second axis Y, the spreading of the current is only prevented by the current blocking layer 5a of the lowest emitter. An advantage of this embodiment over fig. 3A is that the production is simpler, since only one current blocking layer needs to be provided.

Fig. 4 shows a schematic representation of a top view of the laser diode from fig. 1 according to the invention. The metal p-contact 8 is depicted as a wave-shaped pattern in a transparent manner so as not to hide the underlying opening of the current blocking layer 5. In this embodiment, the current blocking layer 5 has an opening. The width W1 of the opening extends in a constant manner in the direction of the first axis Z.

Fig. 5 shows a schematic representation of a top view of the laser diode from fig. 2 according to the present invention. In this embodiment, the current blocking layer 5 has four openings with widths W11, W12, W13, and W14. The widths W11, W12, W13, W14 of the openings remain constant in the direction of the first axis Z. In a preferred embodiment, the widths W11, W12, W13 and W14 of the openings of the current shield have the same dimensions, as a result of which a particularly uniform power distribution along the second axis Y is achieved.

Fig. 6 shows a schematic representation of a top view of a further embodiment of the laser diode from fig. 1 according to the present invention. In this embodiment, six current blocking layers 5 are spaced from each other along the first axis Z by distances L1, L2, L3, L4 and L5. Each of the current blocking layers has openings having the same width W1 and located at the same position with respect to the third axis X. In a preferred embodiment, the distances of the current blocking layers 5 are equidistant, i.e. the distances L1, L2, L3, L4 and L5 have the same dimensions. Thus, a periodic modulation of the current density and thus of the charge carriers injected in the active layer along the first axis Z is achieved, as a result of which the optical laser beam field is also periodically modulated. This can suppress filamentation (filamentation) in the wide stripe laser, thereby improving beam quality.

Fig. 7 shows a schematic representation of a top view of a further embodiment of the laser diode from fig. 1 according to the present invention. In this embodiment, there is a current blocking layer 5 having an opening. The width of the opening in the direction of the third axis X varies along the first axis Z (from W1r to W1 f). This can be used to vary the optical power density along the first axis Z.

Fig. 8 shows a schematic representation of a top view of a further embodiment of the laser diode from fig. 1 according to the present invention. In this embodiment, the current blocking layer also extends along the area of the facets 21, 22 with extensions Lf and Lr along the first axis Z. This shortens the lifetime of the laser.

List of reference numerals

1 Metal n contact

2 first n-type functional layer comprising an n-type carrier substrate

3 active layer

4 first p-type functional layer

5 Carrier substrate

6 boundary surface between first p-type functional layer and second p-type functional layer

7 second p-type functional layer

8 metal p contact

X third axis

Y second axis

First axis of Z

h1 distance of Current Barrier layer from active layer (thickness of non-implanted portion of first p-type layer)

Thickness of d1 Current Barrier layer

Thickness of h2 second p-type layer

Thickness of h3 first p-type layer

First width of opening of W1 current blocking layer

Second width of W2 Metal p contact

Third width of W3 Metal n contact

Width of opening in W11-W14 Current Barrier layer

Width of opening of W1a first current blocking layer

W1b width of opening of second Current blocking layer

Width of opening of current blocking layer on first facet of W1r

Width of opening of current blocking layer on second facet of W1f

L distance of facets (length of resonator)

Distance of current barriers L1-L5

10 tunnel diode

21 first facet

22 second facet

2a-7a first laser

2b-7b second laser