Semiconductor laser and laser device

Abstract

The embodiment of the present application provides a semiconductor laser and a laser device, the semiconductor laser comprises: a substrate layer, a first DBR layer, an extended DBR layer, an active layer, an oxidation layer and a second DBR layer arranged in sequence; wherein the refractive index and the thickness of each layer material in the extended DBR layer are configured so that the difference between the average refractive index of the extended DBR layer and the effective refractive index of the main resonant cavity of the semiconductor laser is less than or equal to 0.03. The semiconductor laser provided by the embodiment of the present application has the effect of small divergence angle and high power output.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a semiconductor laser and laser device. Background Technology

[0002] A VCSEL (Vertical-Cavity Surface-Emitting Laser) is a laser whose emission direction is perpendicular to the surface of the resonant cavity. It is widely used due to its low threshold current and small divergence angle. For example, it can be used as a laser source in vehicle-mounted ranging. With increasingly higher requirements for measurement accuracy, even smaller divergence angles are needed for VCSELs. However, the divergence angle is only one factor; high peak power is also required in vehicle-mounted ranging applications. Therefore, how to design a VCSEL structure that balances small divergence angle and high power characteristics remains an unsolved problem. Summary of the Invention

[0003] Therefore, embodiments of the present invention provide a semiconductor laser and laser device that reduce the divergence angle while maintaining high power characteristics by adding an extended DBR layer.

[0004] This invention provides a semiconductor laser, comprising a substrate layer, a first DBR layer, an extended DBR layer, an active layer, an oxide layer, and a second DBR layer disposed sequentially; wherein the refractive index and thickness of each layer material in the extended DBR layer are configured such that the difference between the average refractive index of the extended DBR layer and the effective refractive index of the main resonant cavity of the semiconductor laser is less than or equal to 0.03.

[0005] This invention also provides a laser device, including the aforementioned semiconductor laser.

[0006] The above embodiments of the present invention have at least one or more of the following beneficial effects: In this embodiment, by adding an extended DBR layer between the first DBR and the active layer, and making the average refractive index of the extended DBR layer close to the effective refractive index of the main resonant cavity of the semiconductor laser, optical impedance matching is achieved, so that the optical field inside the semiconductor laser cavity can be smoothly coupled to the extended DBR layer, thereby extending the internal longitudinal optical field downward. According to the diffraction limit principle, the far-field divergence angle is greatly compressed. At the same time, the extended DBR layer redefines the wave vector dispersion relationship, increases phase mismatch and diffraction loss for higher-order transverse modes, and achieves single-mode high-power output with a small divergence angle. Attached Figure Description

[0007] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0008] Figure 1 This is a schematic diagram of a semiconductor laser provided in an embodiment of the present invention.

[0009] Figure 2 This is a schematic diagram of a semiconductor laser provided in another embodiment of the present invention.

[0010] Figure 3 for Figure 1 The diagram shows the light field intensity distribution and aluminum content of the semiconductor laser.

[0011] Figure 4 for Figure 2 The diagram shows the light field intensity distribution and aluminum content of a specific embodiment of the semiconductor laser.

[0012] Figure 5 This is a pair of proportional light field intensity distribution diagrams and aluminum content diagrams for a semiconductor laser without an extended DBR layer.

[0013] [Explanation of Labels in the Attached Image] 100, Semiconductor laser; 10, First electrode; 20, Substrate layer; 30, First DBR layer; 40, Extended DBR layer; 41, First region; 42, Second region; 43, Third region; 50, Active layer; 60, Oxide layer; 70, Second DBR layer; 80, Second electrode. Detailed Implementation

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0015] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] It should also be noted that the division of multiple embodiments in this invention is only for the convenience of description and should not constitute a special limitation. Features in various embodiments can be combined and referenced in each other without contradiction.

[0018] This invention provides a semiconductor laser 100, comprising a substrate layer 20, a first DBR layer 30, an extended DBR layer 40, an active layer 50, an oxide layer 60, and a second DBR layer 70, which are sequentially disposed therefrom.

[0019] The substrate layer 20 is composed of, for example, GaAs material, specifically n-type GaAs. A first electrode 10 is disposed on the side of the substrate layer 20 facing away from the first DBR layer 30 to facilitate current injection. Corresponding to the substrate layer 20 being an n-type substrate, the first electrode 10 is an n-electrode metal.

[0020] DBR stands for Distributed Bragg Reflector. Therefore, the first DBR layer 30, the extended DBR layer 40, and the second DBR layer 70 are all layer structures formed by alternating pairs of low-refractive-index layers and high-refractive-index layers. For ease of description, a combination of a low-refractive-index layer and its adjacent high-refractive-index layer is referred to as an alternating layer. That is, an alternating layer consists of two layers of materials with different refractive indices.

[0021] For example, the substrate layer 20 is an n-type substrate, and the first DBR layer 30 is an n-type DBR structure. Specifically, in the alternating layers of the first DBR layer 30, the low-refractive-index layer is composed of n-type AlGaAs, and the high-refractive-index layer is composed of n-type GaAs material. The first DBR layer 30 includes, for example, 35 to 40 pairs of high and low refractive-index layers, and the thickness of each pair of high and low refractive-index layers can be, for example, 1 / 4 of the optical thickness of the laser oscillation wavelength, to achieve efficient reflection of the light emitted from the active layer 50.

[0022] The active layer 50 can be, for example, a multiple quantum well layer, which is obtained by alternating growth of InGaAs potential well layers and GaAs barrier layers. When current is injected, electrons and holes recombine here to generate photons.

[0023] Oxide layer 60 can be, for example, aluminum gallium arsenide with a high aluminum content, such as Al. 0.98 Ga 0.02 As is an insulating aluminum oxide layer formed by a wet oxidation process, the oxide layer 60 has oxide pores.

[0024] The first DBR layer 30 is an n-type DBR structure, while the second DBR layer 70 is a p-type DBR structure, for example, composed of p-type AlGaAs and / or p-type GaAs materials. Specifically, the high refractive index layer could be, for example, p-type Al. 0.15 Ga0.85 As, the low refractive index layer may be, for example, p-type Al. 0.9 Ga 0.1 As, it can form a resonant cavity structure with the first DBR layer 30 to ensure effective oscillation of light within the cavity. A second electrode 80 is also disposed on the second DBR layer 70. When a forward bias voltage is applied between the second electrode 80 and the first electrode 10, the current is confined by the oxide layer 60 and injected into the active layer 50. Electrons and holes recombine to generate photons. These photons are reflected back and forth within the cavity formed by the second DBR layer 70 and the first DBR layer 30 to finally form laser light.

[0025] In this embodiment, an extended DBR layer 40 is added between the first DBR layer 30 and the active layer 50. The extended DBR layer 40 has the same doping type as the first DBR layer 30. Taking the first DBR layer 30 as an n-type DBR structure as an example, the extended DBR layer 40 is also an n-type DBR structure. The extended DBR layer 40 may include 8 to 16 pairs of high and low refractive index layers. The specific number of pairs can be calculated based on the target total reflectivity and the desired optical field penetration depth (effective cavity length). Specifically, the alternating layers in the extended DBR layer 40 use a first aluminum-containing material layer and a second aluminum-containing material layer with the same general formula as the low refractive index layer and the high refractive index layer, respectively. The aluminum composition content of the first aluminum-containing material layer and the second aluminum-containing material layer is different. For example, the low refractive index layer and the high refractive index layer in the alternating layers of the extended DBR layer 40 are both Al. x Ga 1-x As material (where x is greater than 0 and less than 1), the value of x in the low-refractive-index material layer (the first aluminum-containing material layer) is higher than the value of x in the high-refractive-index material layer (the second aluminum-containing material layer). The value of x can be determined by analyzing and identifying the elemental composition of the material using secondary ion mass spectrometry (IMS). The thickness of each material layer can be determined using TEM (transmission electron microscopy).

[0026] The refractive index and thickness of each layer within the extended DBR layer 40 can be designed and matched so that the difference between the average refractive index of the extended DBR layer 40 and the effective refractive index of the main resonant cavity of the semiconductor laser 100 is less than or equal to 0.03. Specifically, the average refractive index of the extended DBR layer 40 is calculated by summing the products of the refractive indices and thicknesses of each layer and dividing by the total thickness of the extended DBR layer 40. For example, the thickness (d) of multiple low-refractive-index material layers in the extended DBR layer 40... L ) and refractive index (n L The thicknesses (d) of the multiple high-refractive-index material layers are consistent. H ) and refractive index (nH When consistent, the average refractive index n of the extended DBR layer 40 is... avg =(n H ×d H +n L ×d L ) / (d H +d L The thickness of each layer of the extended DBR layer 40 can be adjusted according to d=λ / (4n), where d is the thickness of the material layer, n is the refractive index of the material layer, and λ is the target emission wavelength of the semiconductor laser 100. In a VCSEL device, the effective refractive index is a general optical macroscopic parameter, referring to the equivalent refractive index experienced when light propagates within a resonant cavity composed of multiple layers of different materials and forms a standing wave. The effective refractive index of the main resonant cavity of the semiconductor laser 100 can be calculated according to the traditional calculation method for the effective refractive index of VCSEL devices. The main resonant cavity of the semiconductor laser 100 can be understood as the region between the side of the extended DBR layer 40 near the active layer 50 and the side of the oxide layer 60 near the active layer 50. Typically, the main resonant cavity can tunnel through structures such as junctions, cladding layers, and active layers. In a specific embodiment of the present invention, the region of the main resonant cavity can be referred to... Figure 3 and Figure 4 The area marked in the middle.

[0027] In some embodiments, the average refractive index of the extended DBR layer 40 is in the range of 3.2 to 3.3, which can be adapted to the effective refractive index requirements of the main resonant cavity of the semiconductor laser 100 with an operating wavelength (i.e., λ) between 850 nm and 980 nm, so that the resonant cavity can achieve the highest stimulated emission efficiency and ensure that the peak of the standing wave is precisely aligned with the active region in the effective refractive index structure.

[0028] In this embodiment, by adding an extended DBR layer 40 between the first DBR layer 30 and the active layer 50, and making the average refractive index of the extended DBR layer 40 close to the effective refractive index of the main resonant cavity of the semiconductor laser 100, optical impedance matching is achieved, so that the optical field inside the semiconductor laser 100 cavity can be smoothly coupled to the extended DBR layer 40, thereby extending the internal longitudinal optical field downward. According to the diffraction limit principle, the far-field divergence angle is greatly compressed. At the same time, the extended DBR layer 40 redefines the wave vector dispersion relationship, increases phase mismatch and diffraction loss for higher-order transverse modes, and realizes single-mode high-power output with a small divergence angle.

[0029] In some embodiments, the refractive index difference between the high-refractive-index material layer and the low-refractive-index material layer of each pair of alternating layers is used as the refractive index difference of the corresponding region. The refractive index difference gradient of the DBR layer 40 increases from the active layer 50 to the first DBR layer 30. For example, for an alternating layer, its refractive index difference = n H -nL , where n H Let n be the refractive index of the high-refractive-index material layer in the pair of alternating layers. L denoted as , where is the refractive index of the low-refractive-index material layer in the pair of alternating layers.

[0030] In some embodiments, the refractive index difference of the extended DBR layer 40 is lower than that of the first DBR layer 30.

[0031] For example, refer to Figure 1 The extended DBR layer 40 includes a first region 41, a second region 42, and a third region 43 arranged sequentially from the active layer 50 to the first DBR layer 30. The refractive index difference between the first region 41, the second region 42, and the third region 43 increases sequentially. Of course, this embodiment is not limited to this, and the extended DBR 40 may also include other numbers of regions, with the refractive index difference gradient increasing among the multiple regions within the extended DBR layer from the active layer 50 to the first DBR layer 30.

[0032] For example, in the alternating layers of the first region 41, the low-refractive-index material layer is Al. 0.65 Ga 0.35 As, the high refractive index material layer is Al. 0.55 Ga 0.45 As. That is, in the alternating layers of the first region 41, the low-refractive-index material layer and the high-refractive-index material layer have the same general formula Al. x Ga 1-x As, the x-coefficient of the low-refractive-index material layer is 0.65, corresponding to a refractive index of 3.19. The x-coefficient of the high-refractive-index material layer is 0.55, corresponding to a refractive index of 3.25. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the first region 41 is 0.1. The average x-coefficient of the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the first region 41 is 0.6. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the first region 41 can be between 0.1 and 0.2. The average refractive index of the first region 41 is between 3.2 and 3.3. The average refractive index of the first region 41 is obtained by dividing the sum of the products of the refractive indices and thicknesses of each layer of refractive index material in the first region 41 by the total thickness of the first region 41. The first region 41 can also be called the low-refractive-index difference region.

[0033] For example, in the alternating layers of the second region 42, the low-refractive-index material layer is Al. 0.75 Ga 0.25 As, the high refractive index material layer is Al. 0.45 Ga 0.55 As. That is, in the alternating layers of the second region 42, the low-refractive-index material layer and the high-refractive-index material layer have the same general formula Al. x Ga1-x As, the x-coefficient of the low-refractive-index material layer is 0.75, corresponding to a refractive index of 3.13. The x-coefficient of the high-refractive-index material layer is 0.45, corresponding to a refractive index of 3.31. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the second region 42 is 0.3. The average x-coefficient of the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the second region 42 is 0.6. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the second region 42 can be between 0.3 and 0.5. The average refractive index of the second region 42 is between 3.2 and 3.3. The average refractive index of the second region 42 is obtained by dividing the sum of the products of the refractive indices and thicknesses of each layer of refractive index material in the second region 42 by the total thickness of the second region 42. The second region 42 can also be called the intermediate refractive index difference region.

[0034] For example, in the alternating layers of the third region 43, the low-refractive-index material layer is Al. 0.85 Ga 0.15 As, the high refractive index material layer is Al. 0.35 Ga 0.65 As. That is, in the alternating layers of the third region 43, the low-refractive-index material layer and the high-refractive-index material layer have the same general formula Al. x Ga 1-x As, the x-coefficient of the low-refractive-index material layer is 0.85, corresponding to a refractive index of 3.07. The x-coefficient of the high-refractive-index material layer is 0.35, corresponding to a refractive index of 3.37. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the third region 43 is 0.5. The average x-coefficient of the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the third region 43 is 0.6. The difference in x between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the third region 43 can be between 0.5 and 0.7, with an average refractive index between 3.2 and 3.3. The average refractive index of the third region 43 is obtained by dividing the sum of the products of the refractive indices and thicknesses of each layer of refractive-index material in the third region 43 by the total thickness of the second region 42. The third region 43 can also be called the high-refractive-index difference region.

[0035] The average refractive index of each region in the extended DBR layer 40 (e.g., the first region 41, the second region 42, or the third region 43) can be calculated using the following formula: = .in, Let be the average refractive index of the region in question. Let be the refractive index of the i-th layer of material in the region in question. Let be the thickness of the i-th layer of material in the desired region. This represents the total thickness of the region in question.

[0036] In the above embodiments, the mean value of x for each pair of alternating layers in the first region 41, the second region 42, and the third region 43 is equal. This ensures that although the refractive indices of the multiple regions differ, their average refractive indices are close to the effective refractive index of the main resonant cavity (the difference is less than or equal to 0.03), which can better enhance the light field intensity.

[0037] Reference Figure 3 ( Figures 3 to 5 The horizontal axis represents distance, the vertical axis on the left represents the x-value, the vertical axis on the right represents the light field intensity, the black line represents the x-value of each material layer, and the red line represents the light field distribution curve. The first region 41, the second region 42, and the third region 43 each include 4 pairs of alternating high and low refractive index layers. Figure 5 The extended DBR layer 40 of this application is not set; the first DBR layer is directly below the active layer, which can... Figure 3 and Figure 5 Compare, based on Figure 5 As can be seen from the light field distribution curve, Figure 5 The region from 20000 to 45000 on the horizontal axis corresponds to the optical field intensity of the main cavity, while the region above 45000 corresponds to the first DBR layer. It can be seen that the optical field intensity approaches 0 around 60000 on the horizontal axis. Figure 3 The region from 45000 to 50000 on the horizontal axis corresponds to the first region 41, where the light field intensity is close to that of the main cavity, and the light intensity decreases relatively slowly with increasing distance. The light field intensity is stronger within the region with an horizontal axis of 60000, approaching more than half of the main cavity's light field intensity. It is evident that compared to the structure without the extended DBR layer 40, this embodiment allows for a longer region with higher light field intensity by incorporating the extended DBR layer 40. In this embodiment, the extended DBR layer 40 is divided into three regions: low, medium, and high (or multiple regions of other types). The lower refractive index difference near the active layer 50 reduces the bandgap barrier for carrier injection. Compared to the high-contrast structure of the traditional first DBR, the region with the low refractive index difference reduces the heterojunction series resistance near the active region (active layer 50), preventing the active region from generating a thermal lensing effect due to overheating. This significantly improves the luminous efficiency and wavelength stability under high-power operation in automotive applications. The region near the first DBR layer 30 has a higher refractive index difference, which provides strong reflection capability, reflecting the expanded and purified base film back to the active layer. This ensures that the laser maintains a high quality factor and low threshold even after the cavity is stretched. A region with a moderate refractive index difference between the high and low refractive index difference regions can act as a spatial phase filter. This gradual phase shift mechanism has minimal impact on the base film but can induce severe phase mismatch in higher-order transverse modes, forcing their energy to be stripped due to diffraction losses, ensuring that single-mode output remains dominant.

[0038] In some embodiments, refer to Figure 2In the extended DBR layer 40, multiple high-refractive-index material layers have the same refractive index, and multiple low-refractive-index material layers have the same refractive index.

[0039] In other embodiments, reference is made to Figure 2 and Figure 4 In the extended DBR layer 40, multiple high-refractive-index material layers have the same refractive index, and multiple low-refractive-index material layers have the same refractive index. Specifically, the material of each layer in the extended DBR layer 40 is Al. x Ga 1-x As, the difference in x between each pair of alternating layers in the extended DBR layer is 0.1~0.2, and the average value of x for each pair of alternating layers is 0.5~0.6. More specifically, the low refractive index material layer in the extended DBR layer 40 is Al. 0.65 Ga 0.35 As, the high refractive index material layer is Al. 0.55 Ga 0.45 As, x is 0.65 in the low-refractive-index material layer and 0.55 in the high-refractive-index material layer. The difference in x between the high and low refractive-index material layers is 0.1, and the average x of the high and low refractive-index material layers is 0.6. At this point, since refractive index matching can be achieved (i.e., the difference between the average refractive index of the extended DBR layer 40 and the effective refractive index of the main resonant cavity of the semiconductor laser is less than or equal to 0.03), and the difference in aluminum content between adjacent layers is small, optically, this structure constitutes a high-sensitivity spatial filter. Through long-range optical penetration, it causes phase mismatch in higher-order modes, which are then stripped away by diffraction loss, ensuring high-purity single-mode output. See also... Figure 4 In the region with an abscissa of 45000 to 64000, although the light field intensity decreases with increasing distance, the rate of decrease is relatively slow, and the minimum intensity can reach more than 0.6 times the intensity of the main cavity. It can be seen that by setting an extended DBR layer 40 with a low aluminum content, this embodiment can make the region with a strong light field longer, and maintain a high light field intensity throughout the entire extended DBR layer 40 region.

[0040] In summary, by adding an extended DBR layer 40 and designing its material layer refractive index and thickness so that the average refractive index of the extended DBR layer 40 is similar to the effective refractive index of the main resonant cavity of the semiconductor laser 100, the requirements for low emission angle and high power characteristics can be met.

[0041] This embodiment also provides a laser device, including the aforementioned semiconductor laser 100. Specifically, the laser device is a vehicle-mounted LiDAR, which has the same effect due to the application of the aforementioned semiconductor laser 100, and will not be described in detail here.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A semiconductor laser, characterized by, include: The substrate layer, the first DBR layer, the extended DBR layer, the active layer, the oxide layer, and the second DBR layer are sequentially arranged; wherein the refractive index and thickness of each layer material in the extended DBR layer are configured such that the difference between the average refractive index of the extended DBR layer and the effective refractive index of the main resonant cavity of the semiconductor laser is less than or equal to 0.

03.

2. The semiconductor laser of claim 1, wherein, The average refractive index of the extended DBR layer ranges from 3.2 to 3.

3.

3. The semiconductor laser of claim 1, wherein, The refractive index difference between the high-refractive-index material layer and the low-refractive-index material layer in each pair of alternating layers in the extended DBR layer is taken as the refractive index difference. The refractive index difference gradient of the extended DBR layer increases from the active layer to the first DBR layer.

4. The semiconductor laser of claim 3, wherein, The extended DBR layer includes a first region, a second region, and a third region arranged sequentially from the active layer to the first DBR layer, with the refractive index difference between the first region, the second region, and the third region increasing sequentially.

5. The semiconductor laser of claim 4, wherein the first and second waveguides are formed by a first and second etch, respectively. The material of each layer of the extended DBR layer is Al. x Ga 1- x As material, the difference in x between the high refractive index material layer and the low refractive index material layer in each pair of alternating layers in the first region is 0.1~0.2, the difference in x between the high refractive index material layer and the low refractive index material layer in each pair of alternating layers in the second region is 0.3~0.5, and the difference in x between the high refractive index material layer and the low refractive index material layer in each pair of alternating layers in the third region is 0.5~0.

7.

6. The semiconductor laser of claim 4, wherein the first and second waveguides are formed by a first and second etch, respectively. In the first region, the second region, and the third region, the mean x values ​​of the high-refractive-index material layer and the low-refractive-index material layer are equal in each pair of alternating layers.

7. The semiconductor laser of claim 4, wherein the first and second waveguides are formed by etching a portion of the first and second cladding layers, respectively. The average refractive index of the first region, the second region, and the third region ranges from 3.2 to 3.

3.

8. The semiconductor laser of claim 1, wherein, The refractive index difference is defined as the difference between the refractive index of each pair of alternating high-refractive-index material layers and low-refractive-index material layers, and the refractive index difference of the extended DBR layer is lower than that of the first DBR layer.

9. The semiconductor laser of claim 1, wherein, The material of each layer of the extended DBR layer is Al. x Ga 1- x As, the difference in x between each pair of alternating high-refractive-index material layers and low-refractive-index material layers in the extended DBR layer is 0.1~0.

2.

10. A laser apparatus, characterized by comprising: Including the semiconductor laser as described in any one of claims 1 to 9.

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