TWI721167B - Edge-emitting laser having small vertical emitting angle - Google Patents

Abstract

An edge-emitting laser having a small vertical emitting angle is disclosed. The edge-emitting laser comprises an upper cladding layer, a lower cladding layer and an active region layer sandwiched between the upper and lower cladding layers. By embedding a passive waveguide layer within the lower cladding layer, an extended lower cladding layer is formed between the passive waveguide layer and the active region layer. In addition, the refractive index (referred as “n-value”) of the passive waveguide layer is larger than the n-value of the extended lower cladding layer. Such passive waveguide layer with larger n-value will guide the light-field to extend downward, in addition, the extended lower cladding layer can separate the passive waveguide layer and the active region layer and thus expand the near-field distribution of laser light-field in the resonant cavity, so as to obtain a smaller vertical emitting angle in the far-field laser light-field.

Description

Edge-fired laser element with small vertical launch angle

The present invention relates to the structure of a photoelectric element, in particular to an edge-fired laser element with a stable and small vertical emission angle designed by using an AlInAS epitaxial layer.

Semiconductor laser or laser diode has the advantages of small size, low power consumption, fast response, impact resistance, long life, high efficiency and low price, so it is widely used in optoelectronics Among the system products, such as: light wave communication, information system, household appliances, precision measurement and optical fiber communication.

Please refer to FIGS. 1 and 2, which are a perspective view and a side view of a typical edge emitting laser diode device, respectively. The typical conventional edge-fired laser device includes a semiconductor substrate 901, a lower cladding layer 902, and a second optical confinement (Separated Confinement Hetero-) sequentially formed on the semiconductor substrate 901 using epitaxial technology. Structure; SCH for short) layer 9031, an active region layer 903, a glazing confined layer 9032, an upper cladding layer 904, and a contact layer 905. Wherein, the contact layer 905 and the upper cladding layer 904 are appropriately formed as a ridge mesa 910.

Generally, the operating principle of the edge-fired laser diode element is that carriers such as electrons and holes are injected into the active layer 903, and are confined by the carrier barrier to the quantum well (Quantum Well) to generate material gain. The limitation principle is that the barrier layer has a higher material energy gap than the quantum well layer, so a lower quantum energy level will be formed in the quantum well, and once the carriers are trapped, it is not easy to escape. The laser light field is confined in the upper and lower SCH layers 9032, 9031 and the active layer 903 by the upper and lower cladding layers 904 and 902. The limitation principle is that the upper and lower cladding layers 904, 902 have a lower optical refractive index (Low Refractive Index) than the upper and lower SCH layers 9032, 9031 and the active layer 903. The light field will be based on the principle of total reflection. A mode is formed and propagated in a material with a relatively high n value. The degree of coupling between the optical field and the quantum well of the active layer 903 determines the modal gain. The higher the modal gain, the easier it is to overcome the optical loss and achieve laserization, and the easier it is to reduce The threshold current value for generating the laser (or called the pumping threshold current; Threshold Current). In order to have a high modal gain, the light field needs to be very concentrated on the active layer 903. However, because the resonant cavity of the edge-fired laser diode element emits light is a rectangular and narrow cavity, and there are Fourier ( Fourier) conversion relationship. When the near field is concentrated, the far field will diverge. This is the higher vertical divergence angle of the laser light 999 emitted by the general edge-fired laser diode element from the light-emitting end 911, which results in the laser light 999. The reason why the cross section will be a long elliptical light in the vertical direction.

Take the conventional edge-fired laser diode device shown in Figure 1 and Figure 2 as an example. If the number of layers, materials, thickness, and doping parameters in the following table 1 are used to make a 2.5G FP epitaxial design structure The conventional edge-fired laser diode element, and the computer model of the edge-fired laser diode element as shown in Figure 3 is used to simulate the near-field and far-field light types (wherein, the ridged platform 910 Set the width of 1.7μm), then the light field simulation results as shown in Figure 4A, Figure 4B and Figure 4C can be obtained. Among them, the structure of the edge-fired laser diode element shown in Figure 3 is actually a schematic diagram of the structure of the edge-fired laser diode element shown in Figure 1 and Figure 2 upside down (that is, in Figure 2). In the third mode, the semiconductor substrate 901 is on the top). From the light field simulation results in Figures 4A to 4C, it can be seen that the divergence angle of the conventional edge-fired laser diode element in the vertical direction is as high as 32.9 degrees, while the divergence angle in the horizontal direction is only 20.28 degrees, resulting in The far-field light pattern presents a long and narrow ellipse in the vertical direction.

Generally speaking, the vertical divergence angle (FWHM) of conventional edge-fired laser diode elements often reaches 30 degrees or more, and the horizontal divergence angle is generally less than 20 degrees, and the field type with worse symmetry The optical efficiency of the fiber couple will appear worse, which is not conducive to back-end applications. Therefore, how to reduce the vertical emission angle of the laser light emitted by the edge-fired laser diode element so that the far-field light pattern can be closer to a circle is the problem to be solved by the present invention.

An object of the present invention is to provide a side-fired laser element, which uses an AlInAS epitaxial layer to design a side-fired laser element with a stable and small vertical emission angle.

To achieve the above objective, the present invention provides an edge-fired laser element with a small vertical emission angle, which includes: an indium phosphide (InP) substrate (Substrate); a bottom cladding (Bottom Cladding) layer located on the substrate Above; an Active Region layer located above the lower cladding layer; a Top Cladding layer located above the active layer; and a contact layer (Contact Layer) located above the upper cladding layer It is characterized in that: a passive waveguide (Passive Waveguide) layer is further sandwiched in the lower cladding layer, and an extended Bottom Cladding (Extended Bottom Cladding) layer is provided between the passive waveguide layer and the active layer, the The extended lower cladding layer is a part of the lower cladding layer; and, a light refraction index (Light Refraction Index) of the passive waveguide layer is greater than the light refraction index of the lower cladding layer.

In a preferred embodiment, the edge-fired laser device of the present invention further includes: a lower optical confinement (SCH) layer, located between the lower cladding layer and the active layer; and an upper optical confinement layer, located Between the active layer and the upper cladding layer.

In a preferred embodiment, the indium phosphide substrate, the lower cladding layer, the passive waveguide layer, and the lower optical confinement layer all have n-typed doping. Both the upper cladding layer and the contact layer have p-typed doping. The material of the lower cladding layer and the upper cladding layer is InP. The material of the active layer is In _1-xy Al _x Ga _y As, where x and y are real numbers between 0 and 1. The material of the contact layer is InGaAs. The material of the low-gloss confined layer and the top-gloss confined layer is In _0.52 Al _0.48 As.

In a preferred embodiment, the passive waveguide layer is a single-layer structure, the material of which is In _0.52 Al _0.48 As, and the thickness is between 0.2 μm and 0.6 μm; and, the passive waveguide layer is located between the passive waveguide layer and the active layer. The thickness of the cladding layer under the extension is between 0.8 μm and 1.6 μm.

In a more preferred embodiment, the thickness of the passive waveguide layer is between 0.4 μm and 0.6 μm; and the thickness of the extended lower cladding layer is between 1.2 μm and 1.4 μm.

In one embodiment, the passive waveguide layer is a multilayer structure, which includes: a lower waveguide layer located on the lower cladding layer, the material of which is InGaAsP, and the thickness is 40 nm; and a spacer layer located on the lower waveguide layer On top, the material is InP with a thickness of 50nm; and an upper waveguide layer is located on the spacer layer, and the material is InGaAsP with a thickness of 40nm; and, it is located between the passive waveguide layer and the active layer The thickness of the cladding layer under the extension is 1.4μm.

In order to further understand the features and technical content of the present invention, please refer to the following detailed descriptions and drawings about the present invention. However, the accompanying detailed descriptions and drawings are only for reference and illustration, and are not used to limit the present invention. .

901‧‧‧Substrate

902‧‧‧Lower cladding layer

9031‧‧‧Low-light limited layer

903‧‧‧Active layer

9032‧‧‧Limited layer of glazing

904‧‧‧Upper coating

905‧‧‧Contact layer

910‧‧‧ridged platform

911‧‧‧light emitting end

999‧‧‧Laser light

301, 401‧‧‧Substrate

302, 402‧‧‧ Lower cladding layer

3021‧‧‧Lower Floor

3022, 4022‧‧‧Extended lower cladding layer

39、49‧‧‧Passive waveguide layer

391‧‧‧Lower waveguide layer

392‧‧‧Interval layer

393‧‧‧Upper waveguide layer

3031, 4031‧‧‧Limited layer under light

303, 403‧‧‧active layer

3032, 4032‧‧‧Limited layer of glazing

304、404‧‧‧Top coating

305、405‧‧‧Contact layer

Figure 1 is a perspective view of a typical conventional edge emitting laser diode device.

Figure 2 is a side view of a typical conventional edge emitting laser diode device.

Figure 3 is a schematic diagram of a computer model of a typical conventional edge-fired laser diode element.

Fig. 4A, Fig. 4B and Fig. 4C are the light field simulation results of the near-field and far-field light patterns based on the computer model shown in Fig. 3, respectively.

FIG. 5 is a schematic diagram of the structure of the first embodiment of the edge-fired laser element of the present invention.

Fig. 6 is a schematic structural diagram of the second embodiment of the edge-fired laser element of the present invention.

FIG. 7A, FIG. 7B, and FIG. 7C show the light field simulation results of the second embodiment of the edge-fired laser diode element of the present invention.

Figure 8A and Figure 8B are graphs drawn based on the data in Table 4 and Table 5, respectively.

The main technical feature of the present invention is that a passive waveguide (Passive Waveguide) layer is sandwiched in the lower cladding layer of the edge-fired laser element, and an extended lower layer is formed between the passive waveguide layer and the active layer. A cladding (Extended Bottom Cladding) layer, the extended lower cladding layer is a part of the lower cladding layer; and, a light refraction index (Light Refraction Index; n value for short) of the passive waveguide layer is greater than the lower cladding layer Coefficient of light refraction of the cladding layer. The passive waveguide layer structure with a high optical refraction coefficient is used to form a passive light guide structure without an active layer structure, thereby inducing the light field to extend toward the substrate, and the passive waveguide is separated by the extended lower cladding layer The distance between the layer and the active layer expands the near-field distribution of the laser light field in the resonant cavity, so a far-field light pattern with a smaller vertical emission angle that is closer to a circle can be obtained.

With reference to FIG. 5, it is a schematic structural diagram of the first embodiment of the edge-fired laser element of the present invention. In the first embodiment of the present invention, the edge-fired laser element from bottom to top includes at least: an indium phosphide (InP) substrate (Substrate) 301, a bottom cladding (Bottom Cladding) layer 302, a A Passive Waveguide layer 39 is sandwiched between the lower cladding layer 302, a lower optical confinement (SCH) layer 3031, an active region layer 303, an upper optical confinement layer 3032, and an upper cladding layer 3031. Cladding layer 304, and a contact layer (Contact Layer) 305. Since the passive waveguide layer 39 is sandwiched between the lower cladding layer 302, the lower cladding layer 302 is divided into upper and lower layers 3021 and 3022; among them are located between the passive waveguide layer 39 and the active layer 303 The part in between may be referred to as an Extended Bottom Cladding layer 3022. The extended lower cladding layer 3022 is a part of the lower cladding layer 302, and a light refraction index (Light Refraction Index) of the passive waveguide layer 39 is greater than the light refraction index of the lower cladding layer 302.

In the first embodiment of the edge-fired laser element of the present invention shown in FIG. 5, the passive waveguide layer 39 is a multilayer structure, which includes, from bottom to top, a lower waveguide layer 391, a spacer layer 392, and An upper waveguide layer 393. Please refer to Table 2, which is one of the specific examples of the number of layers, materials, thicknesses, and doping parameters of each layer structure in the edge-fired laser element of the present invention as shown in Figure 5 (with 2.5G FP as an example).

It can be seen from Table 2 and FIG. 5 that in this embodiment, the lower waveguide layer 391 is located on the lower layer 3021 of the cladding layer, the material of which is InGaAsP, and the thickness is 40 nm. The spacer layer 392 is located on the lower waveguide layer 391, the material is InP, and the thickness is 50 nm. The upper waveguide layer 393 is located on the spacer layer 392, the material of which is InGaAsP, and the thickness is 40 nm. In addition, the thickness of the extended lower cladding layer 3022 located between the passive waveguide layer 39 and the active layer 303 is 1.4 μm. As for the other detailed parameter values of the above-mentioned epitaxial layers of the edge-fired laser diode element, for example, how many layers are there in each layer of material, the proportion of each component, the thickness of each layer, doping type, doping concentration, use The specific values of the dopants can be directly obtained from Table 5, so I will not repeat them.

With the specific structure of the first embodiment of the edge-fired laser diode element of the present invention shown in Figure 5 and Table 2, although the vertical emission angle of the emitted laser light can be reduced to below 28 degrees, However, because the method of this first embodiment is mainly to insert two layers of superlattice semiconductor material (super lattice PQ; for example, InGaAsP~1.165um) in the lower cladding layer 302 of the epitaxial layer close to the InP substrate 301, the high n value The waveguide layer, that is, the lower waveguide layer 391 and the upper waveguide layer 393, but this approach has the following two disadvantages: 1. PQ involves the growth of two five groups, which is difficult to control on epitaxial, so it is easy to cause the variation of refractive index and affect the change of divergence angle; 2. The PQ layer needs a multi-layer design, and the thickness of each layer falls between 10nm-100nm. The manufacturing process is cumbersome and difficult to control.

In view of this, the present invention further provides a second embodiment of the edge-fired laser diode element to solve the above-mentioned shortcomings of the first embodiment, which will be described in detail later.

Please refer to FIG. 6, which is a schematic structural diagram of the second embodiment of the edge-fired laser element of the present invention. In this second embodiment, similarly, the edge-fired laser device is formed on an indium phosphide (InP) substrate (Substrate) 401 in an epitaxial manner to form at least the following epitaxial layers sequentially from bottom to top: A Bottom Cladding layer 402, a Passive Waveguide layer 49 are sandwiched in the lower cladding layer 402, a lower optical confinement (SCH) layer 4031, an active region layer 403, and an upper cladding layer 403. The optical confinement layer 4032, a top cladding layer 404, and a contact layer 405. In this embodiment, the substrate 401 also substantially provides a part of the function of the lower cladding layer 402, and since the passive waveguide layer 49 is sandwiched in the lower cladding layer 302 closest to At the substrate 401, the portion between the passive waveguide layer 49 and the active layer 403 can be referred to as an Extended Bottom Cladding layer 4022. The extended lower cladding layer 4022 is a part of the lower cladding layer 402, and a light refraction index (Light Refraction Index) of the passive waveguide layer 49 is greater than the light refraction index of the lower cladding layer 402.

In the second embodiment of the edge-fired laser element of the present invention shown in FIG. 6, the passive waveguide layer 49 is a single-layer structure, which is a single-layer high n-value AlxGayIn1 with a lattice structure matching (lattice match) -The x-yAs bulk structure forms a passive waveguide (Passive Waveguide) to replace the PQ layer multilayer design in the first embodiment, such as AlInAs, AlGaInAs or InGaAs. The advantages are as follows: 1. The passive waveguide layer 49 only A single group 5 (As) is used, so the epitaxial control is good; 2. The passive waveguide layer 49 is a single bulk film design, and the film thickness falls in the range of 50nm-1000nm, so the process is relatively simple and easy to control.

With this method, the edge-fired laser diode element with a small vertical angle can be manufactured stably and uniformly, and various shortcomings caused by the multi-layer design of the PQ layer in the first embodiment of the present invention can be overcome.

Please refer to Table 3 for the specific implementation of one of the number of layers, materials, thickness, and doping parameter values of each layer structure in the second embodiment of the edge-fired laser element of the present invention as shown in Figure 6. Example (take 2.5G FP as an example).

It can be seen from Figure 6 and Table 3 above that, in the second embodiment of the edge-fired laser diode device of the present invention, the indium phosphide substrate 401, the lower cladding layer 402 (including the extended lower cladding layer 4022 ), the passive waveguide layer 49 and the lower optical confinement layer 4031 both have n-typed doping. Both the upper cladding layer 404 and the contact layer 405 have p-typed doping. The substrate 401, the lower cladding layer 402 (including the extended lower cladding layer 4022) and the upper cladding layer 404 are all InP. The material of the active layer 403 is In1-x-yAlxGayAs, where x and y are real numbers between 0 and 1. The material of the contact layer 405 is InGaAs, and a thinner InGaAsP layer is provided at the bottom of the contact layer 405 near the upper cladding layer 404 in order to transition from InP to InGaAs. The purpose is to make the material energy level more continuous. Reduce resistance. In addition, the material of the lower light confinement layer 4031 and the upper light confinement layer 4032 is In0.52Al0.48As. As for the other detailed parameter values of the above-mentioned epitaxial layers of the edge-fired laser diode element, for example, how many layers are there in each layer of material, the proportion of each component, the thickness of each layer, doping type, doping concentration, use The specific values of the dopants, etc., can be obtained directly from Table 6, so I will not repeat them.

Taking the second embodiment of the edge-fired laser diode device of the present invention shown in Figure 6 as an example, if the number of layers, materials, thickness, and doping parameters as shown in Table 3 above are used to produce 2.5G FP epitaxy Design the structure of the edge-fired laser diode element, and use the computer model of the edge-fired laser diode element as shown in Figure 3 to simulate the near-field and far-field light types (wherein, the ridged platform The width of φ is set at 1.7 μm ), the light field simulation results as shown in Fig. 7A, Fig. 7B and Fig. 7C can be obtained. From the light field simulation results of Figs. 7A to 7C, it can be seen that the second embodiment of the edge-fired laser diode element of the present invention shown in Figs. 6 and Table 3 can effectively reduce the divergence angle in the vertical direction. To 24.73 degrees, and the horizontal divergence angle is 18.28 degrees; therefore, compared with the conventional technology light field simulation results shown in Figures 4A to 4C, the edge-fired laser diode element of the present invention In the second embodiment, it is true that a far-field laser type that is relatively closer to a circle can be obtained. In addition, the present invention also obtains actual measurement data through actual epitaxy and device fabrication, and obtains the actual sample of the edge-fired laser diode device of the present invention manufactured according to the content of the above-mentioned Figure 6 and Table 3. The divergence angle in the vertical direction is 22.49 degrees, and the divergence angle in the horizontal direction is 19.16 degrees. Not only does it have a relatively more circular laser type than the conventional edge-fired laser diode elements, but it is generally The above is also in line with the light field simulation results shown in Figs. 7A to 7C.

The key feature of the present invention is to use a single group 5 (As) and a single layer of InAlGaAs Bulk material to design the passive waveguide layer 49 to achieve a stable and easy to grow small vertical angle laser. The passive waveguide layer 49 is located below the active layer 403 And it is located above the InP substrate 401. The key points of the structure of the present invention include two points: 1. The material of the extended lower cladding layer 4022 is InP, which can provide a small value of n; 2. The material of the passive waveguide layer 49 is AlxGayIn1-x-yAs, which can provide a large value of n.

Therefore, in the present invention, the respective thicknesses of the extended lower cladding layer 4022 and the passive waveguide layer 49 need to be appropriately designed to have a small vertical divergence angle and good laser characteristics at the same time. Generally speaking, the extended lower cladding layer 4022 (material is InP) must have a certain thickness to achieve the effect of expanding the near-field distribution, but an excessively thick design will consume too much epitaxy time, and the appropriate thickness falls in the range of 500nm-2000nm . The passive waveguide layer 49 (the material is AlxGayIn1-x-yAs) must have a certain thickness to effectively induce the light field, but the increase in thickness will sacrifice the modal gain. There is a trade-off between the two, which needs to be fine-tuned. Calculate the best optimized balance. However, if the passive waveguide layer 49 exceeds a certain thickness, it will appear multi-mode and cannot be used, and the appropriate thickness falls within the range of 100 nm-1000 nm. The present invention uses computer simulation to calculate the thickness of the cladding layer 4022 and the passive waveguide layer 49 under different extensions to form an array table. The results are shown in Tables 4 and 5 below to show that the thickness of the cladding layer 4022 under different extensions matches different passive waveguide layers. When the thickness is 49, what are the vertical divergence angles and modal gains that can be obtained.

Among them, Multi means Multi-Mode.

Please also refer to Figure 8A and Figure 8B, which are graphs drawn based on the data in Table 4 and Table 5, respectively.

From the above Table 4 and Table 5, it can be seen that if we hope that the far-field vertical divergence angle of the edge-fired laser element of the present invention can be lower than 30 degrees, and at the same time the modal gain can be higher than 60, then the passive waveguide The thickness of layer 49 (the material is In0.52Al0.48As) can be between 0.2 μ m and 0.6 μ m, and the thickness of the extended lower cladding layer 4022 (the material is InP) is preferably between 0.8 μ m and 1.6 μ m. . If better laser light field and gain performance are desired, in the preferred embodiment of the present invention, the thickness of the passive waveguide layer can be between 0.4 μm and 0.6 μm ; and the extended lower cladding layer The thickness is between 1.2 μ m and 1.4 μ m. At this time, the far-field vertical divergence angle can be lower than about 25 degrees, and at the same time the modal gain can be higher than close to 70 or more, which not only improves the traditional side shooter The far-field vertical divergence angle of the type laser element is often greater than the absence of more than 30 degrees, while maintaining a good modal gain value.

However, the above are only preferred embodiments of the present invention, and should not limit the scope of implementation of the present invention, that is, all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention should still be covered by the patent of the present invention. Scope The scope of the intended protection.

401‧‧‧Substrate

402‧‧‧Lower cladding layer

3021‧‧‧Lower Floor

4022‧‧‧Extended lower cladding layer

49‧‧‧Passive waveguide layer

4031‧‧‧Limited layer under light

403‧‧‧Active layer

4032‧‧‧Limited layer of glazing

404‧‧‧Upper coating

405‧‧‧Contact layer

Claims (10)

An edge-fired laser element with a small vertical emission angle, including: an indium phosphide (InP) substrate (Substrate); a bottom cladding (Bottom Cladding) layer located above the substrate; and an active (Active Region) layer , Located above the lower cladding layer; a top cladding (Top Cladding) layer located above the active layer; and a contact layer (Contact Layer) located above the upper cladding layer; wherein, the contact layer and the upper The cladding layer is appropriately formed as a ridge mesa; it is characterized in that a passive waveguide (Passive Waveguide) layer is sandwiched in the lower cladding layer, and the passive waveguide layer and the active layer There is an Extended Bottom Cladding (Extended Bottom Cladding) layer in between. The extended bottom cladding layer is a part of the bottom cladding layer; and the passive waveguide layer has a light refraction index (Light Refraction Index) greater than the The light refractive index of the lower cladding layer. For example, the edge-fired laser element described in item 1 of the scope of patent application further includes: a lower optical confinement (SCH) layer, located between the lower cladding layer and the active layer; and an upper optical confinement layer, located Between the active layer and the upper cladding layer. The edge-fired laser device described in item 2 of the scope of patent application, wherein: the indium phosphide substrate, the lower cladding layer, the passive waveguide layer and the lower optical confinement layer all have n-type doping (n- typed doping); both the upper cladding layer and the contact layer have p-typed doping; the material of the lower cladding layer and the upper cladding layer is InP; the material of the active layer is In1- x-yAlxGayAs, where x and y are real numbers between 0 and 1; the material of the contact layer is InGaAs; and the material of the lower optical confinement layer and the upper optical confinement layer is In0.52Al0.48As. The edge-fired laser element described in the first item of the scope of patent application, wherein: the passive waveguide layer is a single-layer structure, the material of which is In0.52Al0.48As, and the thickness is between 0.2μm~0.6μm; The thickness of the extended lower cladding layer between the passive waveguide layer and the active layer is between 0.8 μm and 1.6 μm. The edge-fired laser element described in item 4 of the scope of patent application, wherein the thickness of the passive waveguide layer The degree is between 0.4 μm and 0.6 μm; and the thickness of the cladding layer under the extension is between 1.2 μm and 1.4 μm. As for the edge-fired laser element described in the first item of the patent application, the passive waveguide layer is a multilayer structure, which includes: a lower waveguide layer on the lower cladding layer, the material of which is InGaAsP, and The thickness is 40nm; a spacer layer, located on the lower waveguide layer, whose material is InP, and the thickness is between 50nm; and an upper waveguide layer, located on the spacer layer, whose material is InGaAsP, and the thickness is 40nm; In addition, the thickness of the extended lower cladding layer located between the passive waveguide layer and the active layer is 1.4 μm. An edge-fired laser element with a small vertical emission angle is formed in an epitaxial manner on a substrate made of indium phosphide (InP) as the main material. It includes: a passive waveguide (Passive Waveguide) layer , Located above the substrate, its material is In0.52Al0.48As; an extended bottom cladding (Extended Bottom Cladding) layer located above the passive waveguide layer, its material is InP; an active (Active Region) layer located in the extension Above the lower cladding layer, the material is In1-x-yAlxGayAs, where x and y are real numbers between 0 and 1. A top cladding layer, located above the active layer, is made of InP; and a contact layer (Contact Layer), located above the upper cladding layer, the material of which is InGaAs. For example, the edge-fired laser element described in item 7 of the scope of patent application further includes: a lower optical confinement (SCH) layer located between the lower cladding layer and the active layer; and an upper optical confinement layer located on Between the active layer and the upper cladding layer. The edge-fired laser device described in item 2 of the scope of patent application, wherein: the indium phosphide substrate, the lower cladding layer, the passive waveguide layer and the lower optical confinement layer all have n-type doping (n- typed doping); and, both the upper cladding layer and the contact layer have p-typed doping. The edge-fired laser element described in item 1 of the scope of patent application, wherein: the passive waveguide layer is a single-layer structure with a thickness of 0.4μm~0.6μm; and is located between the passive waveguide layer and the active layer The thickness of the cladding layer under the extension is between 1.2 μm and 1.4 μm.

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