Dual-wavelength super-radiation light-emitting diode and preparation method thereof

Abstract

The invention provides a dual-wavelength super-radiation light-emitting diode and a preparation method thereof, and the dual-wavelength super-radiation light-emitting diode comprises a substrate, a first semiconductor cladding, a first light limiting layer, a quantum well active layer, a second light limiting layer and a second semiconductor cladding which are stacked. A ridge waveguide structure is arranged on the surface of one side, far away from the second light limiting layer, of the second semiconductor cladding; wherein the quantum well active layer comprises a first light-emitting layer and a second light-emitting layer, the second light-emitting layer and the first light-emitting layer are arranged on the same layer and adjacent to each other, the first light-emitting layer can emit first light with the wavelength being lambda 1, the second light-emitting layer can emit second light with the wavelength being lambda 2, and lambda 1 is smaller than lambda 2; the ridge waveguide structure is used for guiding the first light and the second light and converging the first light and the second light on the same light-emitting surface for emission. According to the invention, the spectral bandwidth limitation of a single-wavelength device can be obviously broken through, and the requirements of optical fiber sensing, coherent imaging and the like on a wide-spectrum light source can be met; meanwhile, the total output power is improved on the premise that the size of the device is not increased.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronics, and in particular to a dual-wavelength superluminescent light-emitting diode and its fabrication method. Background Technology

[0002] A Super Luminescent Emitting Diode (SLED or SLD) is an optoelectronic device based on the principle of spontaneous emission single-pass amplification. Its core radiation mechanism is amplified spontaneous emission (ASE)—when the gain medium is in a strongly excited state, during forward current injection, electrons in the active region transition to the valence band and recombine with holes to generate photons. These spontaneously emitted photons gain gain as they propagate along the single-pass cavity length, ultimately achieving a single-pass amplification effect. From a performance perspective, the SLD falls between a semiconductor laser (LD) and a light-emitting diode (LED), possessing both the high output power and high energy conversion efficiency of an LD, and the wide spectral output characteristics and low temporal coherence of an LED. This balanced performance makes it a core device in applications with stringent requirements for light source spectral width, power, and coherence (such as fiber optic sensing and coherent imaging).

[0003] As the performance requirements of SLDs in the aforementioned application areas increase, existing technologies are gradually revealing multi-dimensional contradictions, making it difficult to simultaneously meet the comprehensive requirements of "high power, wide spectrum, low ripple, high integration, and low cost." Specific problems are as follows: First, existing technologies control SLD spectral ripple primarily by setting waveguide absorption regions (such as curved waveguides, coupled waveguides, trapezoidal waveguides, etc.)—using these structures to adjust the reflectivity of reflected light, thereby suppressing ripple caused by spectral interference. However, this approach essentially achieves ripple control by "absorbing reflected light," and the absorbed photons cannot participate in effective output, resulting in significant waste of optical power and limiting the potential for increasing device output power. Second, to further improve the absorption rate of reflected light and optimize ripple, some solutions employ multi-quantum-well docking epitaxy technology, utilizing the spectral absorption characteristics of narrow-band quantum wells on broadband quantum well emission to enhance the absorption effect. However, this technology involves complicated processes and is difficult to manufacture. It can only achieve the single function of improving absorption rate, and the investment cost does not match the actual performance benefits, making it difficult to meet the needs of low-cost mass production. Finally, existing multi-wavelength SLD light sources are limited by size design and structural layout, resulting in poor compatibility with micro-optoelectronic devices with high integration requirements (such as micro fiber optic gyroscopes and portable sensing modules). At the same time, if the output characteristics of "high power + wide spectrum" are forcibly pursued, the problem of insufficient light absorption in the active region is likely to occur, resulting in high reflectivity of the reverse light, which ultimately manifests as increased spectral ripple, forming a vicious cycle of "performance improvement - ripple deterioration".

[0004] Therefore, there is an urgent need for a dual-wavelength superluminescent light-emitting diode and its fabrication method to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-wavelength superluminescent light-emitting diode and its fabrication method, which solves the technical problem that dual-wavelength superluminescent light-emitting diodes fabricated by existing processes cannot simultaneously meet the requirements of high power, wide spectrum, low ripple, high integration and low cost.

[0006] To solve the above-mentioned technical problems, the present invention provides a dual-wavelength superluminescent light-emitting diode, comprising a substrate, a first semiconductor cladding, a first light confinement layer, a quantum well active layer, a second light confinement layer, and a second semiconductor cladding, wherein a ridge waveguide structure is provided on the surface of the second semiconductor cladding away from the second light confinement layer; The quantum well active layer includes a first light-emitting layer and a second light-emitting layer. The second light-emitting layer is on the same layer as the first light-emitting layer and is arranged adjacent to it. The first light-emitting layer can emit a first light with a wavelength of λ1, and the second light-emitting layer can emit a second light with a wavelength of λ2, where λ1 < λ2. The ridge waveguide structure is used to guide the first light and the second light to converge and emit them from the same light-emitting surface.

[0007] Preferably, the wavelength difference between the second ray and the first ray is 20~300nm.

[0008] Preferably, the ridge waveguide structure includes, in a clockwise direction, a coupling waveguide, a first arc waveguide, a first strip waveguide, a U-shaped broadband reverse interconnecting waveguide, a second strip waveguide, and a second arc waveguide, with the end of the second arc waveguide connected to the beginning of the coupling waveguide to form a closed loop.

[0009] Preferably, the orthogonal projections of the coupling waveguide, the first arc waveguide, and the first strip waveguide onto the second light-emitting layer are located within the second light-emitting layer; the orthogonal projections of the U-shaped broadband reverse interconnecting waveguide, the second strip waveguide, and the second arc waveguide onto the first light-emitting layer are located within the first light-emitting layer.

[0010] Preferably, the coupling waveguide includes an annular portion and a protruding portion. The annular portion is connected to the first arc-shaped waveguide and the second arc-shaped waveguide, respectively. The protruding portion is integrally formed with the annular portion and is located on the side away from the U-shaped broadband reverse interconnecting waveguide.

[0011] Preferably, the annular portion includes a first side and a second side disposed opposite to each other, the first side being connected to a first arc-shaped waveguide and the second side being connected to a second arc-shaped waveguide; The angle between the first arc-shaped waveguide and the first side surface is greater than the angle between the second arc-shaped waveguide and the second side surface.

[0012] Preferably, the protrusion includes a front end face and a rear end face disposed opposite to each other, the rear end face is connected to the annular portion, the front end face is a light-emitting surface and is coated with an anti-reflection film, the reflectivity of the anti-reflection film is 0.1%~5%.

[0013] Preferably, the two free ends of the U-shaped broadband reverse interconnecting waveguide are equidistant from the apex of its curved section; the length of the first strip waveguide is the same as the length of the second strip waveguide; and the outer ring arc length of the first arc waveguide is less than the outer ring arc length of the second arc waveguide.

[0014] Preferably, the dual-wavelength superluminescent diode further includes an N-type electrode and a P-type electrode, wherein the N-type electrode is disposed on the side surface of the substrate away from the first semiconductor cladding, and the P-type electrode is disposed on the ridge waveguide structure; The P-type electrode includes a first P-type sub-electrode and a second P-type sub-electrode arranged opposite to each other; the first P-type sub-electrode is disposed on the first strip waveguide, and its orthogonal projection area on the first strip waveguide coincides with the first strip waveguide; the second P-type sub-electrode is disposed on the second strip waveguide, and its orthogonal projection area on the second strip waveguide coincides with the second strip waveguide.

[0015] Accordingly, the present invention also provides a method for fabricating a dual-wavelength superluminescent light-emitting diode, the method comprising: S10, a first semiconductor cladding layer, a first optical confinement layer, a quantum well active layer, a second optical confinement layer, and a second semiconductor cladding layer are sequentially grown on the substrate to obtain a primary epitaxial wafer; S20, a mask is grown on a primary epitaxial wafer, and a portion of the first semiconductor cladding, a portion of the first light confinement layer, a portion of the quantum well active layer, a portion of the second light confinement layer, and a portion of the second semiconductor cladding that are not covered by the mask are etched by photolithography. The remaining quantum well active layer serves as the first light-emitting layer. S30, a first semiconductor cladding layer, a first light confinement layer, a second light-emitting layer, a second light confinement layer, and a second semiconductor cladding layer are sequentially grown on a substrate on one side of the first light-emitting layer to obtain a secondary epitaxial wafer; the first light-emitting layer can emit a first light ray with a wavelength of λ1, and the second light-emitting layer can emit a second light ray with a wavelength of λ2, where λ1 < λ2. S40, remove the mask and fabricate a patterned ridge waveguide structure on the secondary epitaxial wafer using photolithography. The ridge waveguide structure is used to guide the first and second rays to converge and emit them from the same light-emitting surface.

[0016] The beneficial effects of this invention are as follows: Unlike the prior art, this invention provides a dual-wavelength superluminescent light-emitting diode and its fabrication method. The dual-wavelength superluminescent light-emitting diode includes a substrate, a first semiconductor cladding, a first optical confinement layer, a quantum well active layer, a second optical confinement layer, and a second semiconductor cladding, all stacked together. A ridge waveguide structure is disposed on the surface of the second semiconductor cladding away from the second optical confinement layer. The quantum well active layer includes a first light-emitting layer and a second light-emitting layer. The second light-emitting layer is co-layered with and adjacent to the first light-emitting layer. The first light-emitting layer can emit a first light ray with a wavelength of λ1, and the second light-emitting layer can emit a second light ray with a wavelength of λ2, where λ1 < λ2. The ridge waveguide structure is used to guide and converge the first and second light rays to the same light-emitting surface for emission. This invention presents a dual-wavelength superluminescent light-emitting diode (SLED) with significant optimizations in multiple dimensions: First, the quantum well active layer contains a first emitting layer (emitting λ1) and a second emitting layer (emitting λ2, λ1 < λ2) that are adjacent to each other on the same layer. The dual-wavelength light rays are converged and superimposed through a ridge waveguide, significantly breaking through the spectral bandwidth limitation of single-wavelength devices and adapting to the requirements of fiber optic sensing, coherent imaging, and other applications requiring a wide-spectrum light source. Second, the dual emitting layers participate simultaneously in spontaneous emission and single-pass gain, increasing the total output power without increasing the device size. The ridge waveguide provides directional guidance and convergence of the dual light rays, reducing transmission loss and improving the effective utilization of light. Finally, the co-layer layout of the dual emitting layers, combined with the integrated ridge waveguide, enables monolithic integration of "dual-wavelength emission—transmission—convergence," eliminating the need for external coupling components, significantly improving integration, and adapting to small-volume, high-integration scenarios such as fiber optic gyroscopes and micro-sensing modules. Attached Figure Description

[0017] Figure 1 A 3D structural schematic diagram of a dual-wavelength superluminescent light-emitting diode provided in an embodiment of the present invention; Figure 2 A top view of a dual-wavelength superluminescent light-emitting diode provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the fabrication method of a dual-wavelength superluminescent diode provided in an embodiment of the present invention; Figure 4 A schematic diagram of the emission spectrum of a dual-wavelength superluminescent light-emitting diode provided in an embodiment of the present invention; In the attached figures: 100—Dual-wavelength superluminescent light-emitting diode; 10—Substrate; 20—First semiconductor cladding; 30—First optical confinement layer; 40—Quantum well active layer; 50—Second optical confinement layer; 60—Second semiconductor cladding; 70—Ridge waveguide structure; 80—P-type ohmic contact structure; 801—First ohmic contact layer; 802—Second ohmic contact layer; 90—P-type electrode; 901—First P-type sub-electrode; 902—Second P-type sub-electrode; 110—N-type electrode; 120—Light-emitting surface. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] To address the shortcomings of existing technologies, this invention provides a dual-wavelength superluminescent diode and its fabrication method. The aim is to fabricate a dual-wavelength chip with partitioned dual quantum wells using docking epitaxy technology. Performance optimization is achieved by relying on the quantum well characteristics of the dual-emitting layer and the synergistic effect of the waveguide structure: the narrow-band quantum well region (corresponding to the second emitting layer) can serve as both a long-wavelength (λ2) emitting region and an absorption region for short-wavelength (λ1) emitting light from the broadband quantum well; while the broadband quantum well region (corresponding to the first emitting layer) can also serve as a reverse waveguide for the long-wavelength (λ2) emitting region, thereby improving the output power of the coupled waveguide long-wavelength light source.

[0020] Meanwhile, the superposition of light from the dual emission regions effectively broadens the spectrum, overcoming the bandwidth limitations of single-wavelength light sources. Addressing the spontaneous unidirectional gain characteristic of dual-wavelength superluminescent diodes—where simply lengthening the emission region to increase power in existing technologies severely degrades spectral ripple—this invention employs a partitioned dual-quantum-well epitaxial structure. By increasing the parallel gain of the dual emission regions, the overall output power of the device is enhanced, structurally avoiding the ripple degradation problem caused by serially extending the cavity length. Furthermore, since the reverse end face (relative to the light-emitting end face) no longer has light attenuation, only a single antireflection coating needs to be deposited at the light-emitting end to meet the requirements. Compared to existing technologies, this reduces one coating process, effectively lowering manufacturing costs and improving product yield.

[0021] The technical solution of this application will now be described in conjunction with specific embodiments.

[0022] Please see Figures 1 to 2 , Figure 1 A 3D structural schematic diagram of a dual-wavelength superluminescent light-emitting diode 100 provided in an embodiment of the present invention; Figure 2 The image shows a top view of a dual-wavelength superluminescent light-emitting diode 100 provided in an embodiment of the present invention. The dual-wavelength superluminescent light-emitting diode 100 includes a substrate 10, a first semiconductor cladding layer 20, a first light confinement layer 30, a quantum well active layer 40, a second light confinement layer 50, and a second semiconductor cladding layer 60 stacked together. A ridge waveguide structure 70 is provided on the surface of the second semiconductor cladding layer 60 away from the second light confinement layer 50. Specifically, the quantum well active layer 40 includes a first light-emitting layer 401 and a second light-emitting layer 402. The second light-emitting layer 402 is disposed on the same layer as the first light-emitting layer 401 and adjacent to it. The first light-emitting layer 401 can emit a first light with a wavelength of λ1, and the second light-emitting layer 402 can emit a second light with a wavelength of λ2, where λ1 < λ2. The ridge waveguide structure 70 is used to guide and converge the first light and the second light onto the same light-emitting surface 120 for emission.

[0023] Furthermore, the dual-wavelength superluminescent diode 100 provided by this invention relies on a stacked structure and a core design of adjacent dual emitting layers (the first emitting layer 401 emits λ1, the second emitting layer 402 emits λ2, and λ1 < λ2) and ridge waveguide-guided convergence to achieve multi-dimensional beneficial effects: In terms of spectral performance, the dual-wavelength light is converged and superimposed through the ridge waveguide, and with the complementary characteristics of narrowband and broadband quantum wells, the spectral width is significantly broadened and the continuity is optimized, making it suitable for high-end requirements such as fiber optic sensing; In terms of power and ripple, the parallel gain of the dual emitting regions increases the output power, and the ridge waveguide and U-shaped broadband reverse interconnecting waveguide 704 reduce transmission loss and absorb reverse light, breaking through the bottleneck of "power increase - ripple deterioration"; In terms of process, by leveraging mature interfacing epitaxy and ridge waveguide technologies, only a single end face needs to be coated with an antireflection film, reducing costs and improving yield; In terms of structure, the co-layer layout of the dual emitting layers and the integrated ridge waveguide achieve monolithic integration of "dual-wavelength emission - transmission - convergence", making it suitable for small-volume, high-integration scenarios such as fiber optic gyroscopes.

[0024] In this embodiment of the invention, the substrate 10 can be InP or GaAs material; the good lattice matching of InP / GaAs ensures the quality of partitioned double quantum well epitaxy, supports the stable emission of light from adjacent double light-emitting layers (λ1, λ2, λ1 < λ2) on the same layer, and achieves broadband output and optimized continuity after being converged and superimposed by ridge waveguide, which is suitable for fiber optic sensing and other requirements; in terms of process, InP / GaAs is compatible with mature docking epitaxy and ridge waveguide fabrication technology, and relies on its stable substrate characteristics to support the implementation of single-end-face coating process, reducing the number of steps to reduce costs and improve yield; in terms of structural integration, the substrate 10 provides reliable support for the double light-emitting layers on the same layer and the integrated ridge waveguide, realizing monolithic integration of "light emission - transmission - convergence", which is suitable for small-volume, high-integration scenarios such as fiber optic gyroscopes.

[0025] In this embodiment of the invention, the first semiconductor cladding 20 is made of InP or AlGaAs material. The low refractive index of the first semiconductor cladding 20 forms a refractive index difference with the first light confinement layer 30 and the quantum well active layer 40, thereby constructing a light field confinement structure, reducing light leakage from the dual light-emitting layers (λ1, λ2) to the substrate 10, providing a basis for optical signal convergence and superposition of ridge waveguides, and supporting wide spectrum and high power output. At the same time, it has good conductivity, which can construct a uniform current channel, ensure stable light emission of the dual light-emitting regions, and help optimize spectral continuity. In addition, it can accurately match the lattice of the substrate 10 and the quantum well active layer 40, providing a flat substrate for docking epitaxy, reducing growth defects, and improving process feasibility with mature fabrication technology.

[0026] In this embodiment of the invention, the first light confinement layer 30 is made of GaInAsP or AlGaAs material, and its refractive index is higher than that of the first semiconductor cladding layer 20 and the quantum well active layer 40 above and below it. By constructing a refractive index gradient, the dual-wavelength light field generated by the first light-emitting layer 401 and the second light-emitting layer 402 can be precisely confined within the quantum well active layer 40, which greatly reduces the leakage loss of light in the direction of the first semiconductor cladding layer 20, provides a strong signal basis for the subsequent convergence and superposition of the ridge waveguide, and directly supports broadband output and high power enhancement. At the same time, its material has good lattice matching with the adjacent layers, ensuring the crystal quality during the docking epitaxial process, reducing growth defects, and helping the dual light-emitting region to emit light stably to optimize spectral continuity.

[0027] In this embodiment of the invention, the quantum well active layer 40 includes a first light-emitting layer 401 and a second light-emitting layer 402. The second light-emitting layer 402 is disposed on the same layer as the first light-emitting layer 401 and adjacent to it. The first light-emitting layer 401 can emit a first light ray with a wavelength of λ1, and the second light-emitting layer 402 can emit a second light ray with a wavelength of λ2, where λ1 < λ2. The quantum well active layer 40 includes a first light-emitting layer 401 (emitting λ1) and a second light-emitting layer 402 (emitting λ2, λ1 < λ2) that are adjacent on the same layer. Both provide dual-wavelength optical signals, which are converged and superimposed by a ridge waveguide to achieve optical emission. The significantly broadened spectral width breaks through the bandwidth limitations of single-wavelength devices, meeting the wide-spectrum requirements of high-end applications. The parallel participation of dual emission regions in spontaneous emission and single-pass gain increases the overall output power without increasing device size or cavity length, while avoiding the spectral ripple degradation problem caused by lengthening a single emission region, achieving synergistic optimization of power and ripple. At the same time, the partitioned design of the dual emission layers is suitable for interfacing epitaxial technology, and the narrowband and broadband quantum wells can form an absorption-waveguide complementary effect, further improving light utilization efficiency and spectral continuity, providing core support for high device performance and process feasibility.

[0028] Specifically, the first light-emitting layer 401 and the second light-emitting layer 402 are precisely controlled by butt-joint regrowth to allow for the individual crystal regeneration of each structural component of the monolithically integrated dual-wavelength superluminescent diode 100. This enables the fabrication of materials with different bandgap wavelengths on the same substrate 10, thereby achieving the goal of optimizing the monolithically integrated device.

[0029] In this embodiment of the invention, the materials of the first emitting layer 401 and the second emitting layer 402 are any one of AlGaInAs, GaInAsP, and GaInP; the wavelength difference between the second light and the first light is 20~300nm. The above design brings multi-dimensional benefits: in terms of spectral performance, the flexible combination of materials is suitable for different wavelength band requirements, good lattice matching ensures spectral continuity, and the reasonable wavelength difference achieves effective superposition of the two spectra without discontinuities, adapting to specific scenarios such as fiber optic sensing and coherent imaging; in terms of power and ripple, the high luminous efficiency of the materials, combined with parallel gain, increases output power, the wavelength difference avoids interference and coupling disorder, and the superimposed waveguide absorbs reverse light to achieve a synergy of wide spectrum and low ripple; in terms of process, the material epitaxy and etching processes are mature and compatible with docking epitaxy, and the wavelength difference can be achieved by adjusting the quantum well, combined with single-end-face coating to reduce costs and improve yield; in terms of structure and application, the narrow linewidth of the materials and the reasonable wavelength difference support the compact integration of the two emitting layers in the same layer, and the ridge waveguide achieves precise spectral output in a small volume, adapting to micro-optical systems and portable devices.

[0030] In this embodiment of the invention, the material of the second light confinement layer 50 is GaInAsP or AlGaAs; wherein, the function of the second light confinement layer 50 is similar to that of the first light confinement layer 30, and will not be described again here.

[0031] In this embodiment of the invention, the material of the second semiconductor cladding 60 is InP or AlGaAs; wherein, the function of the second semiconductor cladding 60 is similar to that of the first semiconductor cladding 20, and will not be described again here.

[0032] In this embodiment of the invention, a ridge waveguide structure 70 with an overall annular design and coupled emission port is provided on the side surface of the second semiconductor cladding 60 away from the second light confinement layer 50. The material of the ridge waveguide structure 70 is GaInAsP or AlGaAs. The ridge waveguide structure 70 is used to guide the first light and the second light to converge and emit them onto the same light-emitting surface 120.

[0033] Specifically, the ridge waveguide structure 70 can precisely guide the dual-wavelength light from the first emitting layer 401 (λ1) and the second emitting layer 402 (λ2) and converge them onto the same emitting surface 120. Combined with the spectral flexibility of mature materials such as AlGaInAs and the reasonable wavelength difference of 20-300nm inherent in the dual emitting layers, it achieves seamless wide-spectrum output through dual-spectrum superposition, adapting to specific scenarios such as high-resolution analysis in fiber optic sensing and large depth-of-field coherent imaging. The convergence process reduces light transmission loss, and the high luminous efficiency of the superimposed materials and the parallel gain of the dual emitting regions significantly improve the overall output. The combined spectrum of the output power is more easily absorbed by structures such as the U-shaped broadband reverse interconnect waveguide 704, avoiding ripple problems caused by wavelengths that are too close or too far, and achieving a synergy of "wide spectrum + high power + low ripple". At the same time, the ridge waveguide and the dual light-emitting layer are adapted to the adjacent layout of the same layer and integrated into a single unit, supporting the small size design of the device to adapt to scenarios such as fiber optic gyroscope micro systems. Moreover, its photolithography etching process is mature and compatible with processes such as docking epitaxy and material etching, further consolidating the feasibility of mass production. Combined with single-end surface coating and other processes, it can reduce costs and improve yield.

[0034] Please see Figures 1 to 2 The ridge waveguide structure 70 includes, in a clockwise direction, a coupling waveguide 701, a first arc-shaped waveguide 702, a first strip waveguide 703, a U-shaped broadband reverse interconnecting waveguide 704, a second strip waveguide 705, and a second arc-shaped waveguide 706, with the end of the second arc-shaped waveguide 706 connected to the beginning of the coupling waveguide 701 to form a closed loop; wherein, the thickness of the above waveguide devices is the same.

[0035] Specifically, a U-shaped broadband reverse interconnecting waveguide 704 is provided between the first strip waveguide 703 and the second strip waveguide 705. Because the first light-emitting layer 401 has a wide quantum well structure, the first light ray with wavelength λ1 is absorbed when passing through the U-shaped broadband reverse interconnecting waveguide 704, and therefore can only be converged from the second strip waveguide 705 through the second arc waveguide 706 to the coupling waveguide 701. Furthermore, because the second light-emitting layer 402 has a narrow quantum well structure, the second light ray with wavelength λ2 can propagate in two directions: in the positive direction, it travels directly from the first strip waveguide 703 through the first arc waveguide 702 to the coupling waveguide 701; in the reverse direction, it travels from the first strip waveguide 703 through the U-shaped broadband reverse interconnecting waveguide 704, the second strip waveguide 705, and the second arc waveguide 706 to reach the coupling waveguide 701. The two rays converge and exit from the coupling waveguide 701, effectively improving the light extraction efficiency.

[0036] In the ridge waveguide structure 70 provided by this invention, the coupling waveguide 701 serves as the core hub for optical signal reception and preliminary modulation. On the one hand, it precisely connects to the dual-emitting layer of the quantum well active layer 40, efficiently receives spontaneously emitted light rays of λ1 and λ2 wavelengths and guides them into the waveguide system. At the same time, it constrains the preliminary regularization of the optical field through waveguide modes, laying the foundation for subsequent transmission and superposition. On the other hand, it also serves as a broadband light source absorption region, absorbing part of the first light rays propagating along the direction from the second strip waveguide 705 to the second arc waveguide 706 in the closed loop, reducing the interference of the reverse light rays of the first light rays on the quantum well active layer 40, and indirectly achieving spectral ripple suppression.

[0037] In the ridge waveguide structure 70 provided by the present invention, the first arc-shaped waveguide 702 connects the coupling waveguide 701 and the first strip waveguide 703. The arc-shaped path enables precise turning of the light transmission direction to adapt to the closed-loop layout and avoid light reflection loss caused by right-angle turning. At the same time, curvature optimization can ensure that the optical field remains synchronized when the λ2 light turns, prevent uneven beam splitting due to the difference in transmission path, ensure the spectral continuity of subsequent light superposition, and adapt to the collaborative requirements of the difference between two wavelengths of 20~300nm.

[0038] In the ridge waveguide structure 70 provided by this invention, the first strip waveguide 703 has a dual core function of injection-emitting light and transmission gain: as the injection-emitting region of the second light beam, its linear low-loss transmission characteristics provide a stable transmission channel for the second light beam (relying on the compatibility of materials such as AlGaInAs to reduce scattering leakage), and enhance the signal intensity of the second light beam through its own injection-emitting light. At the same time, it provides single-pass gain amplification for dual-wavelength light beams in conjunction with the wide gain spectrum characteristics of the material, helping to improve the total output power through parallel gain. Its transmission path connects the first arc-shaped waveguide 702 and the U-shaped broadband reverse interconnected waveguide 704, laying the foundation for the subsequent forward and reverse split transmission of λ2 and the directional transmission of λ1, adapting to the optical field modulation requirements under the closed-loop layout, and further supporting the synergistic realization of wide spectrum output and ripple suppression.

[0039] In the ridge waveguide structure 70 provided by this invention, the U-shaped broadband reverse interconnect waveguide 704 is the core unit for ripple suppression and power optimization, possessing both bidirectional functionality and structural advantages: For the short-wavelength (λ1) broadband light emitted by the first emitting layer 401, the U-shaped structure of the U-shaped broadband reverse interconnect waveguide 704 extends its reverse transmission path, fully attenuating and blocking the reverse interference light by relying on the absorption characteristics of the material, cutting off the λ1 reverse interference path from the source, and effectively reducing spectral ripple; At the same time, the U-shaped broadband reverse interconnect waveguide 704 provides a dedicated directional reverse transmission path for the long-wavelength (λ2) narrowband light emitted by the second emitting layer 402, allowing the λ2 reverse light to pass smoothly and enter the subsequent waveguide, reducing the reverse loss of the λ2 light, and working with the coupling waveguide 701 to achieve dual-path convergence to improve the output power.

[0040] In the ridge waveguide structure 70 provided by this invention, the second strip waveguide 705 has a dual core function of injection-emission and transmission gain: as the injection-emission region of the first ray (λ1), its linear low-loss transmission characteristics provide a stable transmission channel for the first ray and enhance the signal strength of the first ray through its own injection-emission. At the same time, in conjunction with the wide gain spectrum characteristics of the material, it provides single-pass gain amplification for dual-wavelength rays, helping to improve the total output power through parallel gain. Its transmission path connects the second arc-shaped waveguide 706 and the U-shaped broadband reverse interconnected waveguide 704, laying the foundation for the subsequent forward and reverse split transmission of λ2 and the directional transmission of λ1, adapting to the optical field control requirements under the closed-loop layout, and further supporting the synergistic realization of wide spectrum output and ripple suppression.

[0041] In the ridge waveguide structure 70 provided by the present invention, the second arc-shaped waveguide 706 connects the coupling waveguide 701 and the second strip waveguide 705. The arc-shaped path enables precise turning of the light transmission direction to adapt to the closed-loop layout and avoid light reflection loss caused by right-angle turning. At the same time, curvature optimization can ensure that the optical field remains synchronized when the forward light of λ1 and the reverse light of λ2 turn, prevent uneven beam splitting due to the difference in transmission path, ensure the spectral continuity of subsequent light superposition, and adapt to the collaborative requirements of the difference between two wavelengths of 20~300nm.

[0042] Please see Figure 2 The orthographic projections of the coupling waveguide 701, the first arc waveguide 702, and the first strip waveguide 703 onto the second light-emitting layer 402 are located within the second light-emitting layer 402. The orthographic projections of the U-shaped broadband reverse interconnecting waveguide 704, the second strip waveguide 705, and the second arc waveguide 706 onto the first light-emitting layer 401 are located within the first light-emitting layer 401. The reason for this design is as follows: the first light-emitting layer 401 uses a wide quantum well (such as AlGaInAs), corresponding to a short wavelength λ1 (this wavelength is prone to reverse interference, so it needs to be blocked); the second light-emitting layer 402 uses a narrow quantum well, corresponding to a long wavelength λ2 (this wavelength needs to be transmitted through a dual-path to enhance power). The two layers are arranged adjacently on the same layer to form functional partitions. The first light-emitting layer 401 serves as the λ1 reverse light blocking region, corresponding to the above-mentioned projection range, which can enhance the absorption blocking effect. The second light-emitting layer 402 serves as the λ2 dual-path transmission region, corresponding to the projection range of the coupling waveguide 701, etc., supporting the "receive-direction-splitting" link. At the same time, it is compatible with the partitioned projection and docking epitaxial process of the ridge waveguide closed loop, thereby solving the contradiction that a single quantum well cannot simultaneously achieve ripple suppression and power enhancement.

[0043] Furthermore, the design of placing the orthographic projection of the U-shaped broadband reverse interconnect waveguide 704 on the first emitting layer 401 within the first emitting layer 401 allows the U-shaped broadband reverse interconnect waveguide 704 to act close to the initial transmission path of the λ1 reverse light. Relying on the long optical path of the U-shape and the absorption characteristics of the material, it achieves efficient attenuation of λ1 (attenuation rate ≥90%), blocking interference from the source. At the same time, the U-shaped broadband reverse interconnect waveguide 704 needs to be connected to the second strip waveguide 705 (projected on the first emitting layer 401). The projection falling into this layer can accurately dock the port, avoiding the loss of cross-layer connection and ensuring low loss of λ2 reverse transmission. It is also compatible with the adjacent layout of the same layer of dual emitting layers. It can rely on the photolithographic positioning of the emitting layer boundary to reduce etching deviation, is compatible with epitaxial processes and optimizes space utilization, and is suitable for the needs of micro systems.

[0044] In this embodiment of the invention, the coupling waveguide 701 includes an annular portion 7011 and a protrusion 7012. The annular portion 7011 is connected to the first arcuate waveguide 702 and the second arcuate waveguide 706, respectively. The protrusion 7012 is integrally formed with the annular portion 7011 and is located on the side away from the U-shaped broadband reverse interconnecting waveguide 704. The annular portion 7011 includes a first side surface and a second side surface that are disposed opposite to each other. The first side surface is connected to the first arcuate waveguide 702, and the second side surface is connected to the second arcuate waveguide 706. The angle between the first arcuate waveguide 702 and the first side surface is greater than the angle between the second arcuate waveguide 706 and the second side surface.

[0045] Specifically, the forward λ2 light, after long-distance transmission through the first arc-shaped waveguide 702, has a relatively gentle incident angle. The larger angle ensures that it is introduced into the annular portion 7011 with low reflection and low loss. The reverse λ2 light, after multiple bends through the U-shaped broadband reverse interconnecting waveguide 704 and the second strip waveguide 705, has a steeper incident angle. The smaller angle enables the optical field to be precisely aligned with the center of the annular portion 7011, avoiding deflection loss. At the same time, this design reduces the optical path difference between the forward and reverse λ2 light within the annular portion 7011 to less than 50 nm, effectively avoiding interference fringes caused by path difference and further improving the smoothness of the composite spectrum.

[0046] In this embodiment of the invention, the protrusion 7012 includes a front end surface and a rear end surface disposed opposite to each other. The rear end surface is connected to the annular portion 7011, and the front end surface is a light-emitting surface 120 coated with an anti-reflection film. The reflectivity of the anti-reflection film is 0.1% to 5%. The above design can precisely match the dual-wavelength optical characteristics of λ1 and λ2, thereby increasing the average transmittance of the dual wavelengths to over 95% and directly increasing the output power by 20% to 30% to support high-power output. At the same time, it avoids intracavity reflection between the light-emitting surface 120 and the annular portion 7011, reducing internal light energy loss. The extremely low reflectivity of the anti-reflection film can block the backflow of reflected light from the light-emitting surface 120 to the quantum well active layer 40, forming a double guarantee of ripple suppression in conjunction with the U-shaped broadband reverse interconnect waveguide 704.

[0047] In this embodiment of the invention, the distances from the two free ends of the U-shaped broadband reverse interconnect waveguide 704 to the apex of its curved section are equal; the length of the first strip waveguide 703 is the same as the length of the second strip waveguide 705; the outer ring arc length of the first arc waveguide 702 is smaller than the outer ring arc length of the second arc waveguide 706; wherein, the symmetrical design of the U-shaped broadband reverse interconnect waveguide 704 achieves λ2 reverse transmission optical path equalization (loss rate < 1%) and λ1 absorption uniformity (attenuation rate ≥ 90%), and also reduces the interference with the two strip waveguides. Connection loss (reduced to below 0.8%); the first strip waveguide 703 and the second strip waveguide 705 are designed with equal lengths to ensure that the optical path of the straight segment of the λ2 dual path is consistent, with a total optical path difference of <100nm, ensuring that the light intensity deviation is <5% and the superposition efficiency is ≥95%, and adapting to the photolithography process to improve mass production consistency; the outer ring arc length of the first arc waveguide 702 is shorter than that of the second arc waveguide 706, and the angle difference is combined to achieve the optimal steering of the λ2 dual path (optical field overlap ≥90%), compensating for the extra optical path of the U-shaped waveguide to make the total path difference converge.

[0048] Please see Figure 2 The length d1 of the first strip waveguide 703 and the second strip waveguide 705 are both 200~750μm, and the width w is both 2~8μm; the width w of the U-shaped broadband reverse interconnecting waveguide 704 is 2~8μm; the angle θ1 between the first arc waveguide 702 and the first side and the angle θ2 between the second arc waveguide 706 and the second side are both 5~20°; the outer ring arc length of the first arc waveguide 702 and the outer ring arc length of the second arc waveguide 706 are both 50~150μm; the length d2 of the coupling waveguide 701 is 5~20μm.

[0049] In this embodiment of the invention, the dual-wavelength superluminescent light-emitting diode 100 further includes an N-type electrode 110 and a P-type electrode 90. The N-type electrode 110 is disposed on the side surface of the substrate 10 away from the first semiconductor cladding 20, and the P-type electrode 90 is disposed on the ridge waveguide structure 70. The material of the N-type electrode 110 is Au-Ge-Ni alloy, and the material of the P-type electrode 90 is Au-Zn alloy.

[0050] Specifically, the P-type electrode 90 includes a first P-type sub-electrode 901 and a second P-type sub-electrode 902 disposed opposite to each other; the first P-type sub-electrode 901 is disposed on the first strip waveguide 703, and its orthogonal projection area on the first strip waveguide 703 coincides with the first strip waveguide 703; the second P-type sub-electrode 902 is disposed on the second strip waveguide 705, and its orthogonal projection area on the second strip waveguide 705 coincides with the second strip waveguide 705.

[0051] Specifically, the alignment of the projected area of ​​the first P-type sub-electrode 901 on the first strip waveguide 703 with the first strip waveguide 703, and the alignment of the projected area of ​​the second P-type sub-electrode 902 on the second strip waveguide 705 with the second strip waveguide 705, is to achieve precise current control, functional synergy, and improved process reliability. On the one hand, it allows the current to be directionally injected into the two core gain units of the two strip waveguides, avoiding diffusion to non-gain units such as the U-shaped broadband reverse interconnect waveguide 704 (preventing activation of its light emission and resulting in λ1 crosstalk), thereby increasing the current utilization rate to over 90%. At the same time, in conjunction with the strip waveguide, the uniform current injection ensures consistent carrier concentration in both paths, compressing the λ2 dual-path light intensity deviation to within 3%. On the other hand, it avoids interference from the U-shaped broadband reverse interconnect waveguide 704 on the λ1 blocking function.

[0052] Furthermore, the dual-wavelength superluminescent diode 100 also includes a first ohmic contact layer 801 and a second ohmic contact layer 802. The first ohmic contact layer 801 and the second ohmic contact layer 802 form a P-type ohmic contact structure 80. The first ohmic contact layer 801 is located between the first P-type sub-electrode 901 and the first strip waveguide 703, and the second ohmic contact layer 802 is located between the second P-type sub-electrode 902 and the second strip waveguide 705. The materials of the first ohmic contact layer 801 and the second ohmic contact layer 802 are both InGaAs.

[0053] Please see Figure 3 , Figure 3 A flowchart illustrating the fabrication method of a dual-wavelength superluminescent diode 100 provided in an embodiment of the present invention; wherein, the method specifically includes: S10, a first semiconductor cladding layer 20, a first light confinement layer 30, a quantum well active layer 40, a second light confinement layer 50, and a second semiconductor cladding layer 60 are sequentially grown on the substrate 10 to obtain a primary epitaxial wafer.

[0054] S20, a mask is grown on a primary epitaxial wafer, and the portion of the first semiconductor cladding layer 20, the portion of the first light confinement layer 30, the portion of the quantum well active layer 40, the portion of the second light confinement layer 50, and the portion of the second semiconductor cladding layer 60 not covered by the mask are etched by photolithography. The remaining quantum well active layer 40 serves as the first light-emitting layer 401.

[0055] Specifically, step S20 also includes: A SiO2 mask is deposited on an epitaxial wafer. Photolithography is used to retain a portion of the quantum well active layer 40 as the first light-emitting layer 401. The SiO2 mask in the area not where the first light-emitting layer 401 is located is etched away by reactive ion etching (RIE). Then, the epitaxial layer below the area not where the first light-emitting layer 401 is located (including the portion of the first semiconductor cladding 20 not covered by the mask, a portion of the first light confinement layer 30, a portion of the quantum well active layer 40, a portion of the second light confinement layer 50, and a portion of the second semiconductor cladding 60) is etched to form a docking growth region on the substrate 10 on one side of the first light-emitting layer 401.

[0056] S30, a first semiconductor cladding layer 20, a first light confinement layer 30, a second light-emitting layer 402, a second light confinement layer 50, and a second semiconductor cladding layer 60 are sequentially grown on the substrate 10 (docking growth region) on one side of the first light-emitting layer 401 to obtain a secondary epitaxial wafer; the first light-emitting layer 401 can emit a first light with a wavelength of λ1, and the second light-emitting layer 402 can emit a second light with a wavelength of λ2, and λ1 < λ2.

[0057] Specifically, step S30 also includes: By controlling the gas flow rate and partial pressure in the docking growth region using an MOVCD (Metal-Organic Chemical Vapor Deposition) device, a first semiconductor cladding layer 20, a first light confinement layer 30, a second light-emitting layer 402, a second light confinement layer 50, and a second semiconductor cladding layer 60 are sequentially grown in the docking growth region to obtain a secondary epitaxial wafer. Among them, the first light-emitting layer 401 can emit a first light with a wavelength of λ1, and the second light-emitting layer 402 can emit a second light with a wavelength of λ2. The wavelength difference between the first light and the second light is only 20~300nm.

[0058] S40, remove the mask and fabricate a patterned ridge waveguide structure 70 on the secondary epitaxial wafer by photolithography. The ridge waveguide structure 70 is used to guide the first light and the second light to converge and emit them onto the same light-emitting surface 120.

[0059] Specifically, step S40 also includes: First, the SiO2 mask above the first light-emitting layer 401 is removed, and the secondary epitaxial wafer is cleaned. Then, a semiconductor mask is grown on the secondary epitaxial wafer and patterned to obtain a patterned ridge waveguide structure 70. The ridge waveguide structure 70 guides the first and second light rays to converge onto the same light-emitting surface 120. Next, a first ohmic contact layer 801 is deposited on the first strip waveguide 703, and a second ohmic contact layer 802 is deposited on the second strip waveguide 705. Then, a first P-type sub-electrode 901 is formed on the first ohmic contact layer 801, and a second P-type sub-electrode 902 is formed on the second ohmic contact layer 802. The first P-type sub-electrode 901 and the second P-type sub-electrode 902 constitute a P-type electrode 90. Finally, the entire secondary epitaxial wafer is thinned, and an N-type electrode 110 is fabricated on the back side of the substrate 10. An antireflection film is deposited on the light-emitting end face of the secondary epitaxial wafer, with a reflectivity of 0.1-5%.

[0060] Please see Figure 4 , Figure 4 This is a schematic diagram of the emission spectrum of a dual-wavelength superluminescent light-emitting diode 100 provided in an embodiment of the present invention; after applying a working voltage to the N-type electrode 110 and the P-type electrode 90, Figure 4 The spectrum corresponding to λ1 has a strong power density in the short-wavelength region, which is due to the absence of an absorption region in its emitting region and the direct convergence of light through the emitting surface 120 of the coupling waveguide 701, providing intensity support for the short-wavelength part of the wide spectrum. The spectrum corresponding to λ2 is in the middle band, which not only achieves effective connection and extension with the λ1 spectrum, but also significantly improves the ripple effect due to the increased absorption region length and the structural optimization without feedback from the reverse emitting surface 120, making the spectrum smoother and more stable. The spectrum corresponding to λ3 (the composite emission spectrum of the dual-wavelength super-radiative light-emitting diode 100 of this invention, which is presented after multiple structural optimizations, has a wide band, high power density and low ripple) covers a wide wavelength range from λ1 to (λ1+100nm), integrating the high power density advantage of λ1 and the ripple improvement effect of λ2, and finally presenting a wide spectrum with high power density and low ripple, which fully demonstrates the comprehensive effectiveness of the dual-wavelength super-radiative light-emitting diode 100 of this invention in wide spectrum emission and performance optimization.

[0061] The dual-wavelength superluminescent diode 100 provided in this embodiment of the invention has a simple device structure, a mature fabrication method, and exhibits high power, wide spectrum, and low spectral ripple performance. For the emitting region of wavelength λ1 (i.e., the entire epitaxial structure where the first emitting layer 401 is located), no absorption region is set. Instead, the light signal is directly focused by the light-emitting surface 120 of the coupling waveguide 701 located above the second emitting layer 402. This design greatly enhances the intensity of the short-wavelength λ1 light (the first light). In addition, the ridge waveguide structure 70 adopts a ring-shaped optical waveguide design, which can reduce one anti-reflection coating process and simplify the fabrication process. At the same time, for the emitting part of the long-wavelength λ2, the absorption region length is almost doubled by relying on the ring path formed in both directions, and there is no light feedback from the reverse light-emitting surface 120. These two characteristics together contribute to the significant improvement of the device ripple effect.

[0062] Compared with existing devices, the dual-wavelength superluminescent diode 100 provided in this embodiment of the invention has a 50% increase in the light output power of wavelength λ1, a reduction in the spectral ripple of wavelength λ2 from 0.5dB to 0.02dB, and a nearly 30% wider wavelength band (from 40nm to 100nm) due to the integration of wavelengths λ1 and λ2, and an increase in device power, resulting in a 15% improvement in overall light output efficiency.

[0063] Compared with the prior art, the present invention has the following advantages: First, it helps to significantly broaden the spectral width of the device, increasing it from the original 40nm to 100nm; Second, it can enhance the luminescence intensity of long-wavelength spectra and effectively improve its spectral ripple; Third, it can reduce the ripple of short-wavelength spectra and improve spectral stability; Fourth, this process has excellent repeatability and high reliability, making it easy for mass production and significantly improving product yield while reducing production costs.

[0064] In summary, unlike existing technologies, the dual-wavelength superluminescent diode 100 provided in this embodiment of the invention features a dual quantum well. The narrow-band quantum well region (the region where the second emitting layer 402 is located) serves as a reverse interconnecting waveguide connecting two emitting regions with different emission wavelengths. The forward-facing light passes through the broadband quantum well region (the region where the first emitting layer 401 is located) as a coupling waveguide 701. Finally, the light is emitted through the antireflection coating region on the light-emitting side. The above design has the following advantages: 1. The spectral width is greatly broadened by the dual-wavelength emitting chip; 2. The U-shaped broadband reverse interconnecting waveguide serves as both the absorption region of the broadband light source and the reverse waveguide of the narrow-band light source, objectively extending the absorption path of the broadband light source and the light absorption process of the narrow-band light source; 3. The coupling waveguide 701 can also serve as the absorption region of the broadband light source, reducing the adverse effects of the light-emitting surface 120 on the light; 4. The docking growth technology and waveguide technology used are very mature and have high process feasibility.

[0065] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0066] The above embodiments merely illustrate implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A dual-wavelength superluminescent light-emitting diode, characterized in that, The device includes a substrate, a first semiconductor cladding, a first optical confinement layer, a quantum well active layer, a second optical confinement layer, and a second semiconductor cladding, wherein a ridge waveguide structure is provided on the surface of the second semiconductor cladding away from the second optical confinement layer. The quantum well active layer includes a first light-emitting layer and a second light-emitting layer. The second light-emitting layer is disposed on the same layer as the first light-emitting layer and adjacent to it. The first light-emitting layer can emit a first light with a wavelength of λ1, and the second light-emitting layer can emit a second light with a wavelength of λ2, where λ1 < λ2. The ridge waveguide structure is used to guide and converge the first light and the second light to the same light-emitting surface for emission.

2. The dual-wavelength superluminescent light-emitting diode according to claim 1, characterized in that, The wavelength difference between the second ray and the first ray is 20~300nm.

3. The dual-wavelength superluminescent light-emitting diode according to claim 1, characterized in that, The ridge waveguide structure includes, in a clockwise direction, a coupling waveguide, a first arc waveguide, a first strip waveguide, a U-shaped broadband reverse interconnecting waveguide, a second strip waveguide, and a second arc waveguide, with the end of the second arc waveguide connected to the beginning of the coupling waveguide to form a closed loop.

4. The dual-wavelength superluminescent light-emitting diode according to claim 3, characterized in that, The orthographic projections of the coupled waveguide, the first arc waveguide, and the first strip waveguide onto the second luminescent layer are located within the second luminescent layer; the orthographic projections of the U-shaped broadband reverse interconnecting waveguide, the second strip waveguide, and the second arc waveguide onto the first luminescent layer are located within the first luminescent layer.

5. The dual-wavelength superluminescent light-emitting diode according to claim 3, characterized in that, The coupling waveguide includes an annular portion and a protruding portion. The annular portion is connected to the first arc-shaped waveguide and the second arc-shaped waveguide, respectively. The protruding portion is integrally formed with the annular portion and is located on the side away from the U-shaped broadband reverse interconnecting waveguide.

6. The dual-wavelength superluminescent light-emitting diode according to claim 5, characterized in that, The annular portion includes a first side and a second side disposed opposite to each other, the first side being connected to the first arc-shaped waveguide, and the second side being connected to the second arc-shaped waveguide; Wherein, the angle between the first arc-shaped waveguide and the first side surface is greater than the angle between the second arc-shaped waveguide and the second side surface.

7. The dual-wavelength superluminescent light-emitting diode according to claim 5, characterized in that, The protrusion includes a front end face and a rear end face that are disposed opposite to each other. The rear end face is connected to the annular portion. The front end face is the light-emitting surface and is coated with an anti-reflection film. The reflectance of the anti-reflection film is 0.1% to 5%.

8. The dual-wavelength superluminescent light-emitting diode according to claim 3, characterized in that, The distances from the two free ends of the U-shaped broadband reverse interconnecting waveguide to the apex of its curved section are equal; the length of the first strip waveguide is the same as the length of the second strip waveguide; the outer ring arc length of the first arc waveguide is less than the outer ring arc length of the second arc waveguide.

9. The dual-wavelength superluminescent light-emitting diode according to claim 3, characterized in that, The dual-wavelength superluminescent diode further includes an N-type electrode and a P-type electrode. The N-type electrode is disposed on the surface of the substrate away from the first semiconductor cladding, and the P-type electrode is disposed on the ridge waveguide structure. The P-type electrode includes a first P-type sub-electrode and a second P-type sub-electrode disposed opposite to each other; the first P-type sub-electrode is disposed on the first strip waveguide, and its orthogonal projection area on the first strip waveguide coincides with the first strip waveguide; the second P-type sub-electrode is disposed on the second strip waveguide, and its orthogonal projection area on the second strip waveguide coincides with the second strip waveguide.

10. A method for fabricating a dual-wavelength superluminescent light-emitting diode, characterized in that, The method includes: S10, a first semiconductor cladding layer, a first optical confinement layer, a quantum well active layer, a second optical confinement layer, and a second semiconductor cladding layer are sequentially grown on the substrate to obtain a primary epitaxial wafer; S20, a mask is grown on the primary epitaxial wafer, and a portion of the first semiconductor cladding, a portion of the first light confinement layer, a portion of the quantum well active layer, a portion of the second light confinement layer, and a portion of the second semiconductor cladding that are not covered by the mask are etched by photolithography. The remaining quantum well active layer serves as the first light-emitting layer. S30, the first semiconductor cladding layer, the first light confinement layer, the second light-emitting layer, the second light confinement layer, and the second semiconductor cladding layer are sequentially grown on the substrate on one side of the first light-emitting layer to obtain a secondary epitaxial wafer; the first light-emitting layer can emit a first light with a wavelength of λ1, and the second light-emitting layer can emit a second light with a wavelength of λ2, where λ1 < λ2. S40, the mask is removed, and a patterned ridge waveguide structure is fabricated on the secondary epitaxial wafer by photolithography. The ridge waveguide structure is used to guide and converge the first light and the second light to the same light-emitting surface for emission.

Images