Interband cascade laser

Abstract

The present disclosure provides an inter-band cascade laser, comprising: a bottom power supply module and a top power supply module; and an active layer arranged between the bottom power supply module and the top power supply module, the active layer being adapted to provide gain to generate laser light under the power supply of the bottom power supply module and the top power supply module, the active layer comprising a plurality of gain core layers and a plurality of optical confinement layers arranged alternately between two optical confinement layers; wherein the refractive index of the optical confinement layer is greater than the refractive index of the gain core layer, so that the laser light propagates in the active layer and generates a plurality of optical modes, and by adjusting the lasing wavelength of the gain core layer and / or the thickness of the optical confinement layer, the confinement factor of the fundamental mode in the plurality of optical modes is higher than the confinement factor of each high-order mode.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and more specifically, to an interband cascaded laser. Background Technology

[0002] Interband cascaded lasers (ICLs) are mid-infrared semiconductor lasers in the 2-10 micrometer band. Theoretically, increasing the number of cycles in the gain core can increase the emitted laser power. However, the highest power currently available comes from interband cascaded lasers with 7-10 cycles. Increasing the number of cycles to more than 10 does not increase the power. The reason is that although increasing the number of cycles in the gain core can increase the volume of the active layer, it also causes the active layer loss to increase rapidly, resulting in a decrease in the overall performance of the laser.

[0003] Currently, the highest power output of existing interband cascaded lasers operating at room temperature in continuous wave mode comes from devices with 7-cycle gain cores. Increasing the number to 10 cycles presents several challenges. Since each cycle's gain core is composed of a superlattice containing several highly doped superlattice layers, increasing the number of cycles to improve output power leads to two problems: firstly, increased heat generation due to the high thermal resistance of the superlattice structure preventing timely heat dissipation; and secondly, an increase in the number of highly doped superlattice layers significantly increases free carrier losses in optical modes. Therefore, the output power of existing interband cascaded lasers is limited by the maximum number of cycles. Summary of the Invention

[0004] To address at least one technical problem described above and in other aspects in the prior art, embodiments of this disclosure provide an interband cascaded laser that can overcome the limitation of the number of cycles while increasing the output power of the interband cascaded laser.

[0005] Embodiments of this disclosure provide an interband cascaded laser, comprising: a bottom power supply module and a top power supply module; and an active layer disposed between the bottom power supply module and the top power supply module. The active layer is adapted to provide gain to generate laser light when powered by the bottom power supply module and the top power supply module. The active layer includes a plurality of gain core layers and a plurality of optical confinement layers alternately disposed between two optical confinement layers. The refractive index of the optical confinement layers is greater than the refractive index of the gain core layers, so that the laser light propagates within the active layer and generates a plurality of optical modes. By adjusting the lasing wavelength of the gain core layers and / or the thickness of the optical confinement layers, the confinement factor of the fundamental mode among the plurality of optical modes is made higher than the confinement factor of each higher-order mode.

[0006] According to some embodiments of this disclosure, the above-mentioned gain core layer has no less than three layers, and each of the above-mentioned gain core layers is composed of 2-10 sub-gain core layers arranged in parallel periodically.

[0007] According to some embodiments of this disclosure, the optical confinement layer is doped of type n, and the doping concentration is not greater than 2 × 10⁻⁶. 18 cm -3 .

[0008] According to some embodiments of this disclosure, multiple of the above-described gain core layers are configured to have different lasing wavelengths to broaden the gain spectrum and tuning range.

[0009] According to some embodiments of this disclosure, a plurality of the aforementioned optical confinement layers are configured to have different thicknesses to enhance the aforementioned optical modes within a preset gain core layer.

[0010] According to some embodiments of this disclosure, it includes three of the above-described gain core layers, and the above-described optical modes include a fundamental mode and two higher-order modes.

[0011] According to some embodiments of this disclosure, the restriction factor Γ of the fundamental mode in the gain kernel layer is 17.0%; the restriction factors Γ of the two higher-order modes in the gain kernel layer are 7.98% and 11.8%, respectively.

[0012] According to some embodiments of this disclosure, the top power supply module includes: an upper cladding layer disposed on the active layer; an upper contact layer disposed on the upper cladding layer, wherein the active layer, the upper cladding layer, and the upper contact layer form a ridge waveguide on the bottom power supply module; a dielectric insulating layer formed on the top and sidewalls of the ridge waveguide, wherein the surface of the dielectric insulating layer at the top of the ridge waveguide is configured to have a window that allows the laser to be emitted; and a top electrode formed in the window on the surface of the dielectric insulating layer, wherein the top electrode forms an ohmic contact with the upper contact layer.

[0013] According to some embodiments of this disclosure, the bottom power supply module includes: a substrate; a buffer layer disposed on the substrate; a lower cladding layer disposed on the buffer layer, the active layer being formed on the lower cladding layer; and a bottom electrode formed on the surface of the substrate away from the buffer layer, wherein the top electrode and the bottom electrode cooperate to provide power to the active layer.

[0014] According to some embodiments of this disclosure, the refractive indices of the upper cladding and the lower cladding are respectively less than the refractive index of the active layer, so as to limit the propagation of the laser within the active layer.

[0015] According to the embodiments of the present disclosure, the inter-band cascaded laser, by alternately arranging multiple gain core layers and multiple optical confinement layers between two optical confinement layers in the active layer, wherein the refractive index of the optical confinement layer is greater than the refractive index of the gain core layer, enables the laser to propagate in the active layer and generate multiple optical modes. This can overcome the limitation of the number of cycles while reducing the temperature and waveguide loss of the active layer of the multi-cycle inter-band cascaded laser, thereby improving the output power of the inter-band cascaded laser. Attached Figure Description

[0016] Figure 1 This is a structural diagram of an interband cascaded laser according to an illustrative embodiment of the present disclosure;

[0017] Figure 2 This is a structural diagram of an active layer according to an illustrative embodiment of the present disclosure;

[0018] Figure 3 This is an intensity distribution diagram of the optical modes of an interband cascaded laser according to an illustrative embodiment of the present disclosure;

[0019] Figure 4 This is a test curve showing the highest temperature and thermal resistance of the active layer of an inter-band cascaded laser according to an illustrative embodiment of the present disclosure;

[0020] Figure 5 This is a continuous-wave power-voltage-current performance curve of an interband cascaded laser according to an illustrative embodiment of the present disclosure; and

[0021] Figure 6 This is a continuous wave laser spectrum of an interband cascaded laser according to an illustrative embodiment of the present disclosure. Detailed Implementation

[0022] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0024] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0025] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). Similarly, when using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0026] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] Figure 1 This is a structural diagram of an interband cascaded laser according to an illustrative embodiment of the present disclosure. Figure 2 This is a structural diagram of an active layer according to an illustrative embodiment of the present disclosure.

[0028] According to embodiments of this disclosure, such as Figure 1 and Figure 2 As shown, an interband cascaded laser includes a bottom power supply module, a top power supply module, and an active layer. The active layer is disposed between the bottom and top power supply modules and is adapted to provide gain for laser generation when powered by both modules. The active layer includes multiple gain core layers and multiple optical confinement layers alternately disposed between two optical confinement layers. The refractive index of the optical confinement layers is greater than that of the gain core layers, allowing the laser to propagate within the active layer and generate multiple optical modes. By adjusting the lasing wavelength of the gain core layers and / or the thickness of the optical confinement layers, the confinement factor of the fundamental mode among the multiple optical modes is made higher than the confinement factor of each higher-order mode.

[0029] According to the above embodiments of the present disclosure, the inter-band cascaded laser, by alternately arranging multiple gain core layers and multiple optical confinement layers between two optical confinement layers in the active layer, wherein the refractive index of the optical confinement layer is greater than the refractive index of the gain core layer, enables the laser to propagate in the active layer and generate multiple optical modes. This can overcome the limitation of the number of cycles while reducing the temperature and waveguide loss of the active layer of the multi-cycle inter-band cascaded laser, thereby improving the output power of the inter-band cascaded laser.

[0030] According to embodiments of this disclosure, the laser is generated by the transition of electrons injected into the gain core layer, from a high energy level to a low energy level, with the energy difference corresponding to the energy of the photon. After the laser is generated, it propagates within the gain core layer and the optical confinement layer, and is emitted to the outside through a window (described in detail below) provided in the top power supply module.

[0031] According to embodiments of this disclosure, the active layer includes a plurality of gain core layers and a plurality of optical confinement layers alternately disposed between two optical confinement layers, such as... Figure 2 As shown, 101a is the first optical confinement layer, 101b is the first gain kernel layer, 102a is the second optical confinement layer, 102b is the second gain kernel layer, ..., 103a is the Nth optical confinement layer, 103b is the Nth gain kernel layer, and 104a is the (N+1)th optical confinement layer.

[0032] According to an embodiment of the present disclosure, an inter-band cascaded laser can overcome the limitation of the number of cycles while reducing the temperature and waveguide loss of the active layer of the multi-cycle inter-band cascaded laser, thereby increasing the output power of the inter-band cascaded laser and solving the problem of heat accumulation in the superlattice structure caused by simply increasing the number of cycles of the gain core layer.

[0033] According to embodiments of this disclosure, the refractive indices of the multiple optical confinement layers can be set to different values, and the laser will enter the low-refractive-index optical confinement layer from the high-refractive-index optical confinement layer, thereby further reducing waveguide loss.

[0034] According to embodiments of this disclosure, such as Figure 1 As shown, the top power supply module includes an upper cladding layer, an upper contact layer, a dielectric insulating layer, and a top electrode. The upper cladding layer is disposed on the active layer. The upper contact layer is disposed on the upper cladding layer, and the active layer, upper cladding layer, and upper contact layer form a ridge waveguide on the bottom power supply module. The dielectric insulating layer is formed on the top and sidewalls of the ridge waveguide, and the surface of the dielectric insulating layer at the top of the ridge waveguide is configured to have a window that allows laser emission. The top electrode is formed in the window on the surface of the dielectric insulating layer, and the top electrode forms an ohmic contact with the upper contact layer.

[0035] According to embodiments of this disclosure, the refractive indices of the upper cladding and the lower cladding are respectively less than the refractive index of the active layer, so as to limit the propagation of laser within the active layer.

[0036] According to embodiments of this disclosure, the thickness of the dielectric insulating layer is not less than 10 nm.

[0037] According to embodiments of this disclosure, the upper cladding layer thickness is not less than 300 nm, the upper cladding layer is made of an alloy material or superlattice material that matches the substrate lattice, the upper cladding layer is n-type doped, and uniform doping or gradient doping is used, with a doping concentration not less than 1 × 10⁻⁶. 15 cm -3 .

[0038] According to embodiments of this disclosure, the upper contact layer is a single-component material or a binary alloy material, the thickness of the upper contact layer is not less than 3 nm, the upper contact layer is n-type doped, and the doping concentration is not less than 5 × 10⁻⁶. 16 cm -3 .

[0039] According to embodiments of this disclosure, the top electrode material is Au, with a thickness of not less than 50 nm.

[0040] According to embodiments of this disclosure, the width of the ridge waveguide is not less than 4 μm.

[0041] In this implementation, the laser propagates within the active layer, preventing it from leaking into the high-loss substrate and top electrode, thus reducing the waveguide loss of the interband cascaded laser.

[0042] According to embodiments of this disclosure, the upper contact layer is heavily doped, and the top electrode forms an ohmic contact with the upper contact layer, thereby achieving low resistance and reducing the generation of Joule heat.

[0043] According to embodiments of this disclosure, such as Figure 1 As shown, the bottom power supply module includes a substrate, a buffer layer, a lower cladding layer, and a bottom electrode. The buffer layer is disposed on the substrate. The lower cladding layer is disposed on the buffer layer, and the active layer is formed on the lower cladding layer. The bottom electrode is formed on the surface of the substrate away from the buffer layer, and the top electrode and the bottom electrode cooperate to provide power to the active layer.

[0044] According to embodiments of this disclosure, the buffer layer serves to reduce defects introduced by the substrate, such as dislocations and point defects, thereby improving the material quality of the upper layer structure.

[0045] According to embodiments of this disclosure, the substrate thickness is 50 μm to 350 μm, and the substrate material includes, but is not limited to, InAs, GaAs, Si, and GaSb semiconductor materials. The substrate is n-type doped with a doping concentration of not less than 1 × 10⁻⁶. 15 cm -3 .

[0046] According to embodiments of this disclosure, the buffer layer is made of a single-component material, alloy material, compositionally graded alloy, or chirped superlattice material that matches the crystal lattice of the substrate material. The thickness of the buffer layer is not less than 50 nm, and the buffer layer is n-type doped with a doping concentration of not less than 1 × 10⁻⁶. 15 cm -3 .

[0047] According to embodiments of this disclosure, the thickness of the lower cladding layer is not less than 500 nm, the lower cladding layer is made of an alloy material or superlattice material that matches the substrate lattice, the lower cladding layer is n-type doped, and uniform doping or gradient doping is used, with a doping concentration of not less than 1 × 10⁻⁶. 15 cm -3 .

[0048] According to embodiments of this disclosure, the bottom electrode is made of GeAuNiAu or GeAuPtAu material.

[0049] According to embodiments of the present disclosure, the epitaxial layer includes a buffer layer, a lower cladding layer, an active layer, an upper cladding layer, and an upper contact layer sequentially grown on a substrate.

[0050] According to embodiments of this disclosure, there are at least three gain core layers, and each gain core layer is composed of 2-10 sub-gain core layers arranged in parallel periodically.

[0051] According to embodiments of this disclosure, there are at least four optical confinement layers.

[0052] According to embodiments of this disclosure, the optical confinement layer is n-type doped with a doping concentration not exceeding 2 × 10⁻⁶. 18 cm -3 .

[0053] According to embodiments of the present disclosure, multiple gain core layers are configured to have different lasing wavelengths to broaden the gain spectrum and tuning range. According to alternative embodiments of the present disclosure, multiple gain core layers are configured to have the same lasing wavelength to increase gain.

[0054] According to embodiments of this disclosure, the lasing wavelength is in the 2μm-10μm band. This enables the achievement of enhanced peak output power.

[0055] According to embodiments of the present disclosure, multiple optical confinement layers are configured with different thicknesses to enhance optical modes within a predetermined gain core layer. According to alternative embodiments of the present disclosure, the multiple optical confinement layers are configured with the same thickness to ensure uniform distribution of multiple optical modes within multiple gain core layers. According to embodiments of the present disclosure, the thickness of the optical confinement layers is 100 nm to 2000 nm.

[0056] In this implementation, the optical modes are distributed in an appropriate proportion in the gain core layer and the optical confinement layer, which satisfies the gain condition of the interband cascaded laser and reduces the loss of the optical modes caused by the absorption of free carriers in the active layer. This reduces the overall waveguide loss of the interband cascaded laser and increases the output power of the interband cascaded laser.

[0057] According to embodiments of this disclosure, the interband cascaded laser includes three gain core layers, and the optical modes include a fundamental mode and two higher-order modes.

[0058] According to embodiments of this disclosure, the refractive index of the optical confinement layer is greater than that of the gain core layer. A three-layer structure consisting of two gain core layers and one optical confinement layer allows for the propagation of laser light in multiple optical modes. Among these optical modes, the fundamental mode is a point with no zero optical intensity in the high-refractive-index layer; points with one, two, three…N zero optical intensity in the high-refractive-index layer are called first-order, second-order, third-order…N-order modes, collectively referred to as higher-order modes.

[0059] In one illustrative embodiment, the active layer of the interband cascaded laser includes three alternately arranged gain core layers and four optical confinement layers, with the fundamental mode being the position of lowest light intensity.

[0060] According to embodiments of this disclosure, see Figure 3 The confinement factor Γ of the fundamental mode in the gain kernel layer is 17.0%. The confinement factors Γ of the two higher-order modes in the gain kernel layer are 7.98% and 11.8%, respectively. In this paper, the confinement factor is the ratio of the optical intensity integral at the three positions of the fundamental mode and the two higher-order modes to the overall optical intensity integral.

[0061] Figure 3 This is an intensity distribution diagram of the optical modes of an interband cascaded laser according to an illustrative embodiment of the present disclosure.

[0062] According to embodiments of this disclosure, the active layer of the interband cascaded laser includes three alternately arranged gain core layers and four optical confinement layers. Each gain core layer includes four periodically arranged sub-gain core layers, totaling 12 periods. Figure 3 As shown, TE0 is the fundamental mode, and its confinement factor Γ in the gain kernel layer is 17.0%. TE1 and TE2 are two higher-order modes, and their confinement factors Γ in the gain kernel layer are 7.98% and 11.8%, respectively. The fundamental mode TE0 of the active layer has the highest gain and is preferentially lased.

[0063] Figure 4 This is a test graph showing the highest temperature and thermal resistance of the active layer of an inter-band cascaded laser according to an illustrative embodiment of the present disclosure.

[0064] According to embodiments of this disclosure, the active layer of the interband cascaded laser includes three alternately arranged gain core layers and four optical confinement layers. Each gain core layer includes four periodically arranged sub-gain core layers, totaling 12 periods. Figure 4 As shown, the active layer of the inter-band cascaded laser of this embodiment is compared with that of a conventional 12-cycle single-core inter-band cascaded laser. The dots represent the test results of the inter-band cascaded laser of this embodiment, the squares represent the test results of the conventional 12-cycle single-core inter-band cascaded laser, the two slanted dot and square curves represent the test curves for the highest temperature of the active region, and the two horizontal dot and square curves represent the test curves for thermal resistance. When the input power is 0.5W, the highest temperature of the active layer of this embodiment is slightly lower. As the input power increases, the rate of increase of the highest temperature of the active layer of this embodiment is significantly less than that of the conventional 12-cycle single-core inter-band cascaded laser. Simultaneously, the thermal resistance of the active layer of this embodiment is significantly lower than that of the active layer of the conventional 12-cycle single-core inter-band cascaded laser.

[0065] Figure 5 This is a power-voltage-current performance curve of a band-cascaded laser according to an illustrative embodiment of the present disclosure.

[0066] According to embodiments of this disclosure, when the substrate is a GaSb semiconductor material, the continuous wave optical power-voltage-current performance curves under different injection currents are as follows: Figure 5 As shown, the threshold current of the interband cascaded laser is 120mA, and the maximum optical power is 615mW. Figure 5 The left curve in the figure represents the voltage performance curve, and the right curve represents the optical power performance curve.

[0067] Figure 6 This is a continuous wave laser spectrum of an interband cascaded laser according to an illustrative embodiment of the present disclosure.

[0068] According to embodiments of this disclosure, the active layer of the interband cascaded laser includes three alternately arranged gain core layers and four optical confinement layers. The test results of the long-range intensity distribution in the fast axis direction are as follows: Figure 6 As shown, the dotted curve represents the laser spectrum of this disclosure, and the square curve represents the laser spectrum of a conventional 12-cycle single-core inter-band cascaded laser. The full width at half maximum (FWHM) of the inter-band cascaded laser in this embodiment is 45 degrees, while the full WHM of the conventional 12-cycle single-core inter-band cascaded laser is 69 degrees.

[0069] In this implementation, the active layer of this disclosure can achieve a smaller divergence angle in the fast axis direction, thereby improving the beam quality of the interband cascaded laser.

[0070] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure, and the shapes and dimensions of the components in the drawings do not reflect actual size and proportion, but are only schematic representations of the embodiments of this disclosure.

[0071] Unless otherwise stated, the numerical parameters in this specification and the appended claims are approximate values ​​and can be varied according to desired characteristics derived from the content of this disclosure. Specifically, all figures used in the specification and claims to indicate composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. Generally, this means that a specific amount varies by ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments.

[0072] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the corresponding elements does not imply that the element has any ordinal number, nor does it represent the order of one element with another element, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a named element to be clearly distinguished from another element with the same name.

[0073] Furthermore, unless specifically described or required to occur in a specific order, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. Moreover, the above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments.

[0074] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A bandgap cascaded laser, comprising: Bottom power supply module and top power supply module; as well as An active layer is disposed between the bottom power supply module and the top power supply module. The active layer is adapted to provide gain to generate laser when powered by the bottom power supply module and the top power supply module. The active layer includes a plurality of gain core layers and a plurality of optical confinement layers alternately disposed between two optical confinement layers. The refractive index of the optical confinement layer is greater than that of the gain core layer, so that the laser propagates within the active layer and generates multiple optical modes. By adjusting the lasing wavelength of the gain core layer and / or the thickness of the optical confinement layer, the confinement factor of the fundamental mode among the multiple optical modes is made higher than that of each higher-order mode.

2. The interband cascaded laser according to claim 1, wherein, The gain core layer has no fewer than three layers, and each gain core layer is composed of 2-10 sub-gain core layers arranged in parallel periodically.

3. The interband cascaded laser according to claim 1, wherein, The optical confinement layer is n-type doped with a doping concentration of no more than 2 × 10⁻⁶. 18 cm -3 .

4. The interband cascaded laser according to claim 1, wherein, The multiple gain core layers are configured to have different lasing wavelengths to expand the gain spectrum and tuning range.

5. The interband cascaded laser according to claim 1, wherein, The plurality of optical confinement layers are configured to have different thicknesses to enhance the optical modes within the preset gain core layer.

6. The interband cascaded laser according to claim 1, wherein, It includes three gain core layers, and the optical mode includes a fundamental mode and two higher-order modes.

7. The interband cascaded laser according to claim 6, wherein, The restriction factor Γ of the fundamental mode in the gain kernel layer is 17.0%; The restriction factors Γ for the two higher-order modes in the gain kernel layer are 7.98% and 11.8%, respectively.

8. The interband cascaded laser according to any one of claims 1-7, wherein, The top power supply module includes: An upper cladding layer is disposed on the active layer; An upper contact layer is disposed on the upper cladding layer, and the active layer, the upper cladding layer, and the upper contact layer form a ridge waveguide on the bottom power supply module; A dielectric insulating layer is formed on the top and sidewalls of the ridge waveguide, and the surface of the dielectric insulating layer at the top of the ridge waveguide is configured to have a window that allows the laser to exit; and A top electrode is formed in the window on the surface of the dielectric insulating layer, and the top electrode forms an ohmic contact with the upper contact layer.

9. The interband cascaded laser according to claim 8, wherein, The bottom power supply module includes: Substrate; A buffer layer is disposed on the substrate; A lower cladding layer is disposed on the buffer layer, and the active layer is formed on the lower cladding layer; and A bottom electrode is formed on the surface of the substrate away from the buffer layer, and the top and bottom electrodes cooperate to provide electrical energy to the active layer.

10. The interband cascaded laser according to claim 9, wherein, The refractive indices of the upper cladding and the lower cladding are respectively less than the refractive index of the active layer, so as to restrict the propagation of the laser within the active layer.

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