A superluminescent diode
By optimizing the waveguide structure design, including the short curved waveguide absorption region, the straight waveguide emission region, and the long curved waveguide absorption region, combined with the high-transmittance film and non-absorption region, the problems of complex SLD fabrication and spectral ripple were solved, achieving stable performance with high power and wide spectrum output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HENAN SHIJIA PHOTONS TECH
- Filing Date
- 2023-02-23
- Publication Date
- 2026-07-03
AI Technical Summary
Existing superluminescent diodes (SLDs) are complex to fabricate, prone to spectral ripple, and sensitive to cavity surface reflections.
The waveguide structure design includes a short curved waveguide absorption region, a straight waveguide light emission region, and a long curved waveguide absorption region. Combined with a high-transmittance film and a non-absorption region, the optical path is optimized to reduce reflectivity and increase light absorption.
It achieves high power and wide spectrum output with spectral ripple of less than 0.2dB, and features a simple structure and stable performance.
Smart Images
Figure CN116093238B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of light-emitting diodes, and particularly relates to a superluminescent light-emitting diode. Background Technology
[0002] Superluminescent diodes (SLDs) are a type of light source that falls between semiconductor lasers (LDs) and light-emitting diodes (LEDs), and are widely used in fields such as fiber optic gyroscopes and optical coherence tomography (OCT). Fiber optic gyroscopes are widely used in inertial navigation and are often referred to as the "eyes" of weapons, possessing significant military value. In civilian applications, fiber optic gyroscopes are widely used in unmanned vehicles and drones. Optical coherence tomography is widely used in eye treatment and diagnostic materials. Superluminescent diodes are a commonly used and important light source for both of these technologies, making the research of high-performance superluminescent diodes extremely significant.
[0003] SLDs (Superluminescent Diodes) offer performance between LDs (Light Detectors) and LEDs (LEDs), requiring the combination of the high power and efficiency of LDs with the broad spectrum and low temporal coherence of LEDs. Therefore, fabricating high-performance SLDs necessitates novel and specialized structural designs. To achieve broad spectrum and low spectral ripple, patent publication CN114388666A discloses a superluminescent diode chip and its fabrication method. This chip, from bottom to top, comprises a substrate, a light confinement layer below the active region, and an active region. The active region includes an active gain region, with absorption regions formed at both ends through docking growth. The photoluminescence wavelength (PL) of the multi-quantum wells in the two absorption regions is greater than that of the multi-quantum wells in the active gain region. This patent uses a docking epitaxial structure to enhance light absorption; however, this method requires multiple epitaxial growth cycles, increasing fabrication difficulty and cost. In addition, patent publication number CN101197407A discloses a superluminescent diode. This patent uses a device structure that combines a straight waveguide and a single-bent waveguide, but it still cannot effectively suppress spectral ripple when the power is high or the temperature is low. Summary of the Invention
[0004] To address the technical problems of existing superluminescent light-emitting diodes (SLDs) being complex to fabricate and sensitive to cavity surface reflections, which easily generate spectral ripple, this invention proposes a superluminescent light-emitting diode with a simple SLD structure and high power, wide spectrum, and low spectral ripple performance.
[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:
[0006] A superluminescent diode includes a substrate with an epitaxial material grown on its front side. A waveguide structure is formed on the upper surface of the epitaxial material. The waveguide structure includes a short curved waveguide absorption region, a straight waveguide light-emitting region, and a long curved waveguide absorption region connected end-to-end. The length of the long curved waveguide absorption region is greater than the length of the short curved waveguide absorption region. The long curved waveguide absorption region is located at one end of the front cavity surface, and the short curved waveguide absorption region is located at one end of the rear cavity surface. The front end face of the long curved waveguide absorption region is the light-emitting surface. Electrodes are provided on the straight waveguide light-emitting region to form an electro-emitting region.
[0007] Preferably, the waveguide structure is S-shaped or C-shaped.
[0008] Preferably, the rear end of the short curved waveguide absorption region is connected to a non-waveguide absorption region, the length of which is 10-100 μm and the width is consistent with the maximum width of the superluminescent diode.
[0009] Preferably, the length of the straight waveguide emitting region is greater than the length of the long curved waveguide absorbing region, and the ratio of the length of the straight waveguide to the length of the long curved waveguide is 2:1.
[0010] Preferably, the angle between the long curved waveguide absorption region and the optical axis is 2-10°, and the angle between the short curved waveguide absorption region and the optical axis is 2-10°.
[0011] Preferably, the radius of curvature of the long curved waveguide absorption region is 1000–5000 μm, and the radius of curvature of the short curved waveguide absorption region is 1000–5000 μm.
[0012] Preferably, the width of the central straight waveguide emitting region is 1–250 μm, the width of the long curved waveguide absorbing region is 2–5 μm, and the width of the short curved waveguide absorbing region is 2–5 μm.
[0013] Preferably, the waveguide structure includes a straight waveguide emitting region, a long curved waveguide absorbing region, and a coupling waveguide. The long curved waveguide is located at one end of the front cavity surface, the straight waveguide emitting region and the coupling waveguide are located at one end of the rear cavity surface, and the coupling waveguide is located on the side of the straight waveguide emitting region. The straight waveguide emitting region and the coupling waveguide are coupled in optical field. The straight waveguide emitting region is connected to the long curved waveguide absorbing region, and the front end face of the long curved waveguide absorbing region is the light-emitting surface. Electrodes are provided on the straight waveguide emitting region to form an electro-emitting region.
[0014] Preferably, the coupling waveguide is a strip waveguide, but it can also be a ring structure or an arc structure, etc.
[0015] Preferably, the front cavity surface of the superluminescent diode is coated with a high-transmittance film, and the rear cavity surface is coated with a high-transmittance film.
[0016] Preferably, the epitaxial material on the front side of the substrate includes, from bottom to top, a semiconductor cladding layer, a lower waveguide layer, a quantum well region, and an upper waveguide layer, and an N-side electrode is provided on the back side of the substrate, while a P-side electrode is provided on the straight waveguide light-emitting region.
[0017] The beneficial effects of this invention are as follows: The upper end of the straight waveguide emitting region has an electrode that serves as the emitting unit of the entire device. The long curved waveguide absorption region is designed to reduce the residual reflectivity of the front cavity surface and increase light absorption; the short curved waveguide absorption region is also designed to reduce the reflectivity of the rear cavity surface and increase light absorption. The long and short curved waveguide absorption regions effectively reduce the residual reflectivity of the light source cavity surface, thereby reducing spectral ripple. Furthermore, since the non-absorbing region lacks a waveguide structure, when light reaches the rear cavity surface for reflection, the amount of light entering the waveguide structure is further reduced due to mode mismatch, thus further suppressing spectral ripple. The addition of a coupling waveguide couples the light into it, increasing the absorption length of the reflected light and reducing the proportion of reflected light coupled into the straight waveguide, which also reduces spectral ripple. The SLD structure prepared by this invention is simple, possesses high power and wide spectral output performance, and has a flat output spectrum, effectively reducing spectral ripple generation, with a maximum spectral ripple of less than 0.2 dB. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a three-dimensional schematic diagram of a superluminescent diode with a double-bend waveguide structure.
[0020] Figure 2 This is a top view of a superluminescent diode with an S-shaped double-bend waveguide structure.
[0021] Figure 3 This is a top view of a superluminescent diode with a C-type double-bend waveguide structure.
[0022] Figure 4 This is a top view of a superluminescent diode with an S-shaped structure and a double-bent waveguide structure with a non-waveguide absorption region.
[0023] Figure 5 This is a top view of a superluminescent diode with a C-type structure and a double-bent waveguide structure with a non-waveguide absorption region.
[0024] Figure 6This is a top view of a superluminescent diode with a double-bent waveguide structure where the width of the emitting region of the straight waveguide is greater than the width of the absorbing region of the bent waveguide.
[0025] Figure 7 This is a top view of a superluminescent diode with a double-bent waveguide structure where the width of the emitting region of the straight waveguide is smaller than the width of the absorbing region of the bent waveguide.
[0026] Figure 8 This is a top view of a coupled waveguide type superluminescent diode.
[0027] Figure 9 This is a spectral analysis of a superluminescent diode with a double-bend waveguide structure.
[0028] Figure 10 The current-power-voltage diagram is for a superluminescent diode with a double-bent waveguide structure.
[0029] In the figure: 101, straight waveguide light-emitting region; 102, long curved waveguide absorption region; 103, short curved waveguide absorption region; 104, front cavity surface; 105, rear cavity surface; 106, width of the long curved waveguide absorption region; 107, width of the short curved waveguide absorption region; 108, width of the straight waveguide light-emitting region; 109, non-waveguide absorption region; 110, width of the straight waveguide light-emitting region on the rear cavity surface; 111, coupled waveguide; 112, length of the coupled waveguide; 113, width of the coupled waveguide; 114, spacing between the coupled waveguide and the straight waveguide light-emitting region; 201, substrate; 202, semiconductor cladding; 203, lower waveguide layer; 204, quantum well region; 205, upper waveguide layer. Detailed Implementation
[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0031] A type of superluminescent light-emitting diode, such as Figure 1As shown, the substrate includes an InP or GaAs substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate 201 includes a semiconductor cladding layer 202 of InP or AlGaAs material, a lower waveguide layer 203 of GaInAsP or AlGaAs material, a quantum well region 204 of AlGaInAs, GaInAsP, or GaInP material, and an upper waveguide layer 205 of GaInAsP or AlGaAs material. An N-plane electrode is provided on the back side of the substrate 201. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. Because the short, curved waveguide absorption region 103 and the long, curved waveguide absorption region 102 have different bending directions, the waveguide structure has an S-shaped or C-shaped shape. The length of the long curved waveguide absorption region 102 is greater than the length of the short curved waveguide absorption region 103. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104, and the short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105. The front end surface of the long curved waveguide absorption region 102 is the light-emitting surface. A P-surface electrode is provided on the straight waveguide light-emitting region 101, which is the injection light-emitting region. Furthermore, a high-transmittance film is deposited on the front cavity surface 104 and the rear cavity surface 105 of the superluminescent diode.
[0032] Furthermore, a non-waveguide absorption region 109 can be provided at the rear end of the short curved waveguide absorption region 103. The length of the non-absorbing waveguide region is 10-100 μm, and its width is consistent with the maximum width of the superluminescent diode.
[0033] The length of the straight waveguide emitting region 101 is greater than the length of the long curved waveguide absorbing region 102, and the ratio of the length of the straight waveguide emitting region 101 to the length of the long curved waveguide absorbing region 102 is 2:1.
[0034] The angle between the long curved waveguide absorption region 102 and the optical axis is 2-10°, and the angle between the short curved waveguide absorption region 103 and the optical axis is 2-10°.
[0035] The radius of curvature of the long curved waveguide absorption region 102 is 1000-5000 μm, and the radius of curvature of the short curved waveguide absorption region 103 is 1000-5000 μm. The curvatures of the long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 can be the same or different.
[0036] The width 108 of the intermediate straight waveguide emitting region is 1–250 μm. Furthermore, the width 110 of the straight waveguide emitting region on the rear cavity surface can be different from the width 108. The width 106 of the long curved waveguide absorbing region is 2–5 μm, and the width 107 of the short curved waveguide absorbing region is 2–5 μm. The widths of the intermediate straight waveguide emitting region 101, the long curved waveguide absorbing region 102, and the short curved waveguide absorbing region 103 can be different.
[0037] Alternatively, a coupling waveguide 111 can be used instead of the short curved waveguide absorption region 103. Its waveguide structure includes a straight waveguide light-emitting region 101, a long curved waveguide absorption region 102, and a coupling waveguide 111. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104, the straight waveguide light-emitting region 101 and the coupling waveguide 111 are located at one end of the rear cavity surface 105, and the coupling waveguide 111 is located on the side of the straight waveguide light-emitting region 101. The straight waveguide light-emitting region 101 and the coupling waveguide 111 are coupled in the optical field. The straight waveguide light-emitting region 101 is connected to the long curved waveguide absorption region 102, and the front end face of the long curved waveguide absorption region 102 is the light-emitting surface. Electrodes are provided on the straight waveguide light-emitting region 101 to form an electro-emitting region.
[0038] Example 1
[0039] A type of superluminescent light-emitting diode, such as Figure 1 and 2 As shown, the substrate includes an InP substrate with an epitaxial material grown on its front side. From bottom to top, the epitaxial material on the front side of the substrate comprises a semiconductor cladding layer (InP), a lower waveguide layer (GaInAsP), a quantum well region (AlGaInAs), and an upper waveguide layer (GaInAsP). An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. This waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102, connected end-to-end. The short, curved waveguide absorption region 103 has a length of 150 μm, an angle θ2 with the optical axis of 6°, a radius of curvature of 1435 μm, and a width of 2 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 2 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 7°, a radius of curvature of 3692.47 μm, and a width of 2 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have opposite bending directions, and the waveguide structure has an S-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 is provided with a P-surface electrode and is the electro-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end face of the long curved waveguide absorption region 102 is the light-emitting surface.
[0040] Figure 9The spectrum of the superluminescent diode with the double-bend waveguide structure in Example 1 is shown. Its 3dB spectral width is 60nm, and the entire spectrum is flat with a maximum spectral ripple of less than 0.2dB.
[0041] Figure 10 The current-power-voltage curve of the superluminescent diode with a double-bent waveguide structure in Example 1 is shown. At 260mA, the power reaches 12.5mW.
[0042] Example 2
[0043] A type of superluminescent light-emitting diode, such as Figure 3 As shown, the substrate includes an InP substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate includes a semiconductor cladding layer (InP), a lower waveguide layer (GaInAsP), a quantum well region (AlGaInAs), and an upper waveguide layer (GaInAsP). An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. The short, curved waveguide absorption region 103 has a length of 150 μm, an angle θ2 with the optical axis of 6°, a radius of curvature of 1435 μm, and a width of 2 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 2 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 7°, a radius of curvature of 3692.47 μm, and a width of 2 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have the same bending direction, and the waveguide structure has a C-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 is provided with a P-surface electrode and is the injection-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end face of the long curved waveguide absorption region 102 is the light-emitting surface.
[0044] Example 3
[0045] A type of superluminescent light-emitting diode, such as Figure 4As shown, the device includes a GaAs substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate comprises a semiconductor cladding layer (AlGaAs), a lower waveguide layer (AlGaAs), a quantum well region (InGaAs), and an upper waveguide layer (AlGaAs). An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. The short, curved waveguide absorption region 103 has a length of 200 μm, an angle θ2 with the optical axis of 10°, a radius of curvature of 1151.75 μm, and a width of 3 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 3 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 10°, a radius of curvature of 2591.44 μm, and a width of 3 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have opposite bending directions, and the waveguide structure has an S-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 has a P-surface electrode, which is the injection light-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end of the long curved waveguide absorption region 102 is the light-emitting surface. The rear end of the short curved waveguide absorption region 103 also has a non-waveguide absorption region 109. The length of the non-absorbing waveguide region is 10 μm, and its width is consistent with the maximum width of the superluminescent diode. The non-waveguide absorption region 109 can reduce the effective reflectivity of the mode and suppress spectral ripple.
[0046] Example 4
[0047] A type of superluminescent light-emitting diode, such as Figure 5As shown, the device includes a GaAs substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate comprises a semiconductor cladding layer (AlGaAs), a lower waveguide layer (AlGaAs), a quantum well region (InGaAs), and an upper waveguide layer (AlGaAs). An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. The short, curved waveguide absorption region 103 has a length of 200 μm, an angle θ2 with the optical axis of 8°, a radius of curvature of 1437.05 μm, and a width of 2 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 2 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 6°, a radius of curvature of 4305.04 μm, and a width of 2 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have the same bending direction, and the waveguide structure has a C-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 has a P-surface electrode, which is the injection light-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end of the long curved waveguide absorption region 102 is the light-emitting surface. The rear end of the short curved waveguide absorption region 103 also has a non-waveguide absorption region 109. The length of the non-absorbing waveguide region is 50 μm, and its width is consistent with the maximum width of the superluminescent diode. The non-waveguide absorption region 109 can reduce the effective reflectivity of the mode and suppress spectral ripple.
[0048] Example 5
[0049] A type of superluminescent light-emitting diode, such as Figure 6As shown, the substrate includes an InP substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate includes a semiconductor cladding layer of AlGaAs, a lower waveguide layer of GaInAsP, a quantum well region of InGaAs, and an upper waveguide layer of AlGaAs. An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. The short, curved waveguide absorption region 103 has a length of 150 μm, an angle θ2 with the optical axis of 6°, a radius of curvature of 1435 μm, and a width of 5 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 250 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 7°, a radius of curvature of 3692.47 μm, and a width of 5 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have opposite bending directions, and the waveguide structure has an S-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 has a P-surface electrode, which is the injection-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end of the long curved waveguide absorption region 102 is the light-emitting surface. The rear end of the short curved waveguide absorption region 103 also has a non-waveguide absorption region 109. The length of the non-absorbing waveguide region is 100 μm, and its width is the same as the maximum width of the superluminescent diode. The non-waveguide absorption region 109 can reduce the effective reflectivity of the mode and suppress spectral ripple.
[0050] Example 6
[0051] A type of superluminescent light-emitting diode, such as Figure 7As shown, the substrate includes an InP substrate. An epitaxial material is grown on the front side of the substrate. From bottom to top, the epitaxial material on the front side of the substrate includes a semiconductor cladding layer of InP, a lower waveguide layer of GaInAsP, a quantum well region of GaInAsP, and an upper waveguide layer of InP. An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a short, curved waveguide absorption region 103, a straight waveguide light-emitting region 101, and a long, curved waveguide absorption region 102 connected end-to-end. The short, curved waveguide absorption region 103 has a length of 150 μm, an angle θ2 with the optical axis of 6°, a radius of curvature of 1435 μm, and a width of 2 μm. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 1 μm. The long, curved waveguide absorption region 102 has a length of 450 μm, an angle θ1 with the optical axis of 7°, a radius of curvature of 3692.47 μm, and a width of 2 μm. The long curved waveguide absorption region 102 and the short curved waveguide absorption region 103 have opposite bending directions, and the waveguide structure has an S-shaped structure. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104 and is also the light-emitting end. The straight waveguide light-emitting region 101 has a P-surface electrode, which is the injection light-emitting region. The short curved waveguide absorption region 103 is located at one end of the rear cavity surface 105, and the front end of the long curved waveguide absorption region 102 is the light-emitting surface. The rear end of the short curved waveguide absorption region 103 also has a non-waveguide absorption region 109. The length of the non-absorbing waveguide region is 10 μm, and its width is consistent with the maximum width of the superluminescent diode. The non-waveguide absorption region 109 can reduce the effective reflectivity of the mode and suppress spectral ripple.
[0052] Example 7
[0053] A type of superluminescent light-emitting diode, such as Figure 8As shown, the substrate includes an InP substrate with epitaxial material grown on its front side. From bottom to top, the epitaxial material on the front side of the substrate comprises a semiconductor cladding layer (InP), a lower waveguide layer (GaInAsP), a quantum well region (AlGaInAs), and an upper waveguide layer (GaInAsP). An N-plane electrode is provided on the back side of the substrate. A waveguide structure is provided on the upper surface of the epitaxial material. This waveguide structure includes a straight waveguide, a long curved waveguide, and a coupling waveguide 111. The long curved waveguide absorption region 102 is located at one end of the front cavity surface 104, while the straight waveguide light-emitting region 101 and the coupling waveguide 111 are located at one end of the rear cavity surface 105. The straight waveguide light-emitting region 101 is parallel to the coupling waveguide 111, and they are optically coupled. The straight waveguide light-emitting region 101 is connected to the long curved waveguide, with the front end of the long curved waveguide serving as the light-emitting surface. Electrodes are provided on the straight waveguide to form an electro-emitting region. The straight waveguide light-emitting region 101 has a length of 900 μm and a width of 2 μm. The long curved waveguide absorption region 102 has a length of 450 μm, an angle of 7° with the optical axis, a radius of curvature of 3692.47 μm, and a width of 2 μm. The coupling waveguide 111 is a strip waveguide with a width 113 of 2 μm, a length 112 of 300 μm, and a distance 114 of 1 μm between the coupling waveguide and the straight waveguide emitting region. The distance between the straight waveguide emitting region 101 and the coupling waveguide controls the coupling strength of the mode, thereby controlling the intensity of the optical mode reaching the rear cavity surface 105, thus controlling the absorption of the mode and controlling the spectral ripple.
[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A superluminescent light-emitting diode, characterized in that, The system includes a substrate (201), on which an epitaxial material is grown. A waveguide structure is provided on the upper surface of the epitaxial material. The waveguide structure includes a straight waveguide light-emitting region (101), a long curved waveguide absorption region (102), and a coupling waveguide (111). The long curved waveguide is located at one end of the front cavity surface (104), and the straight waveguide light-emitting region (101) and the coupling waveguide (111) are located at one end of the rear cavity surface (105). The coupling waveguide (111) is located on the side of the straight waveguide light-emitting region (101). The straight waveguide light-emitting region (101) and the coupling waveguide (111) are coupled by light field. The straight waveguide light-emitting region (101) is connected to the long curved waveguide absorption region (102). The front end of the long curved waveguide absorption region (102) is the light-emitting surface. An electrode is provided on the straight waveguide light-emitting region (101) to form an electro-emitting region.
2. The superluminescent diode according to claim 1, characterized in that, The length of the straight waveguide emitting region (101) is greater than the length of the long curved waveguide absorbing region (102), and the ratio of the length of the straight waveguide to the length of the long curved waveguide is 2:
1.
3. The superluminescent diode according to claim 2, characterized in that, The angle between the long curved waveguide absorption region (102) and the optical axis is 2-10°.
4. The superluminescent diode according to claim 3, characterized in that, The radius of curvature of the long curved waveguide absorption region (102) is 1000-5000 μm.
5. The superluminescent diode according to claim 4, characterized in that, The width (108) of the emitting region of the straight waveguide is 1~250um, and the width (106) of the absorbing region of the long curved waveguide is 2~5um.
6. The superluminescent diode according to claim 5, characterized in that, The front cavity surface (104) of the superluminescent diode is coated with a high-transmittance film, and the rear cavity surface (105) is coated with a high-transmittance film.
7. The superluminescent diode according to claim 6, characterized in that, The epitaxial material on the front side of the substrate (201) includes, from bottom to top, a semiconductor cladding layer (202), a lower waveguide layer (203), a quantum well region (204), and an upper waveguide layer (205). The back side of the substrate (201) is provided with an N-side electrode, and the straight waveguide light-emitting region (101) is provided with a P-side electrode.