Semiconductor laser with power monitoring
By simultaneously fabricating the laser and detector within a semiconductor laser, and using an insulating filling layer to encapsulate and electrically isolate the optical coupling, the high packaging cost problem in existing technologies is solved, achieving the effect of integrated power monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUXI HUAXING OPTOELECTRONICS RES CO LTD
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-19
AI Technical Summary
Existing semiconductor lasers require external detectors for power monitoring during application, which increases packaging costs.
Design a semiconductor laser with built-in power monitoring. By fabricating the laser and detector simultaneously during the manufacturing process, an insulating filling layer is used to wrap the laser ridge layer and the detector coupling layer, and optical coupling is established to achieve electrical isolation and optical coupling.
Power monitoring of semiconductor lasers was achieved without increasing manufacturing and packaging costs, thus reducing packaging costs.
Smart Images
Figure CN119674696B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photonic optoelectronic device design technology, and in particular to a semiconductor laser with built-in power monitoring. Background Technology
[0002] Semiconductor lasers have a wide range of applications, including spectroscopy, photochemistry, medicine, biology, integrated optics, pollution monitoring, semiconductor material processing, optical device performance evaluation, optical integrated circuit testing, quantum optical information processing, and communication. Therefore, it is evident that semiconductor lasers have important applications in many fields. However, during application, external detectors are usually required to monitor the operating status of semiconductor lasers, which increases packaging costs. Summary of the Invention
[0003] The purpose of this invention is to provide a semiconductor laser with built-in power monitoring, so that the laser and detector can be fabricated simultaneously during the manufacturing process, solving the problem of power monitoring in the later stage and reducing packaging costs.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] A semiconductor laser with built-in power monitoring includes a lower electrode layer, a substrate layer, a lower capping layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, a laser ridge layer, a detector coupling layer, and an insulating filler layer. The lower electrode layer, the substrate layer, the lower capping layer, the lower waveguide layer, the multi-quantum well layer, and the upper waveguide layer are stacked sequentially from bottom to top. The laser ridge layer, the detector coupling layer, and the insulating filler layer are all disposed on the upper waveguide layer. The detector coupling layer is spaced apart from the laser ridge layer. The insulating filler layer partially encloses the laser ridge layer and the detector coupling layer, exposing the first upper electrode layer at the upper end of the laser ridge layer and the second upper electrode layer at the upper end of the detector coupling layer. The detector coupling layer is electrically isolated from the laser ridge layer and optically coupled.
[0006] In one embodiment of this application, the laser ridge layer includes a lower ridge layer, a middle ridge layer, and an upper ridge layer stacked sequentially from bottom to top. The lower ridge layer is an InP ridge lower layer or an InAlGaAs ridge lower layer that has undergone P-type modulation doping. The middle ridge layer is an InGaAs ridge middle layer that has undergone P-type modulation doping. The upper ridge layer is the first upper electrode layer, which includes a first titanium layer and a first gold layer stacked sequentially from bottom to top.
[0007] In one embodiment of this application, the laser ridge layer has a dimension of 150μm to 4000μm along a first direction perpendicular to the stacking direction, and the laser ridge layer has a dimension of 2μm to 100μm along a second direction perpendicular to the stacking direction. The first direction is perpendicular to the second direction, and the laser ridge layer has a dimension of 0.9μm to 1.2μm along the stacking direction.
[0008] In one embodiment of this application, the detector coupling layer includes a curved strip portion and a cylindrical portion. A first end of the curved strip portion is close to the laser ridge layer, and a second end of the curved strip portion extends in a direction away from the laser ridge layer. The second end of the curved strip portion is connected to the cylindrical portion.
[0009] In one embodiment of this application, the dimension of the curved strip portion along a first direction perpendicular to the stacking direction is 20μm~30μm, the dimension of the curved strip portion along a second direction perpendicular to the stacking direction is 2μm~3μm, the first direction is perpendicular to the second direction, the dimension of the curved strip portion along the stacking direction is 0.9μm~1.2μm, the diameter of the cylindrical portion is 50μm~60μm, and the dimension of the cylindrical portion along the stacking direction is 0.9μm~1.2μm.
[0010] In one embodiment of this application, the detector coupling layer includes a lower coupling layer, a middle coupling layer, and an upper coupling layer stacked sequentially from bottom to top. The lower coupling layer is an InP coupling lower layer or an InAlGaAs coupling lower layer with P-type modulation doping. The middle coupling layer is an InGaAs coupling middle layer with P-type modulation doping. The upper coupling layer is a second upper electrode layer, which includes a second titanium layer and a second gold layer stacked sequentially from bottom to top.
[0011] In one embodiment of this application, the lower electrode layer includes a third gold layer and a third titanium layer stacked sequentially from bottom to top, or the lower electrode layer includes a third gold layer and a gold-germanium-nickel layer stacked sequentially from bottom to top, wherein the dimension of the third gold layer along the stacking direction is not less than 300 nm, and the dimension of the third titanium layer or the gold-germanium-nickel layer along the stacking direction is not less than 40 nm.
[0012] In one embodiment of this application, the substrate layer is an N-type modulated doped GaAs substrate layer or an InP substrate layer, and the size of the substrate layer along the stacking direction is 100μm~120μm.
[0013] In one embodiment of this application, the lower capping layer is an InP lower capping layer or an AlGaAs lower capping layer that has undergone N-type modulation doping, and the dimension of the lower capping layer along the stacking direction is not less than 1.6 μm.
[0014] In one embodiment of this application, the lower waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer. The dimension of the lower waveguide layer along the stacking direction is not less than 0.5 μm. The refractive index of the lower waveguide layer gradually increases from bottom to top, and the maximum refractive index value does not exceed 3.55.
[0015] In one embodiment of this application, the multiple quantum well layer is an InGaAs multiple quantum well layer or an InGaAsP multiple quantum well layer. The size of the multiple quantum well layer along the stacking direction is 10nm~120nm. The multiple quantum well layer includes 1~9 quantum wells, the thickness of the well layer is 3nm~9nm, and the thickness of the barrier layer is 5nm~12nm.
[0016] In one embodiment of this application, the upper waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer. The size of the upper waveguide layer along the stacking direction is not less than 0.9 μm. The refractive index of the upper waveguide layer gradually decreases from bottom to top, and the minimum refractive index value is not less than 2.9.
[0017] In one embodiment of this application, the insulating filler layer is a silicon oxide layer or a silicon nitride layer.
[0018] As can be seen from the above technical solution, the present invention discloses a semiconductor laser with built-in power monitoring. The semiconductor laser with built-in power monitoring includes a lower electrode layer, a substrate layer, a lower capping layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, a laser ridge layer, a detector coupling layer, and an insulating filling layer. The lower electrode layer, substrate layer, lower capping layer, lower waveguide layer, multi-quantum well layer, and upper waveguide layer are stacked sequentially from bottom to top. The laser ridge layer, detector coupling layer, and insulating filling layer are all disposed on the upper waveguide layer. The detector coupling layer is arranged alternately with the laser ridge layer. The insulating filling layer partially encloses the laser ridge layer and the detector coupling layer, exposing the first upper electrode layer at the upper end of the laser ridge layer and the second upper electrode layer at the upper end of the detector coupling layer. The detector coupling layer is electrically isolated from the laser ridge layer and establishes optical coupling.
[0019] It is evident that during the fabrication process of the aforementioned semiconductor laser with built-in power monitoring, both the laser ridge layer and the detector coupling layer are fabricated on top of the upper waveguide layer. Compared with existing single semiconductor lasers, this achieves the purpose of power monitoring of the semiconductor laser without increasing manufacturing and packaging costs. Attached Figure Description
[0020] 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.
[0021] Figure 1 This is a schematic diagram of the structure of a semiconductor laser with built-in power monitoring provided in an embodiment of the present invention;
[0022] Figure 2 This is a top view of a semiconductor laser with built-in power monitoring provided in an embodiment of the present invention.
[0023] In the picture:
[0024] 1 is the lower electrode layer; 2 is the substrate layer; 3 is the lower capping layer; 4 is the lower waveguide layer; 5 is the multiple quantum well layer; 6 is the upper waveguide layer; 7 is the laser ridge layer; 8 is the detector coupling layer; 801 is the curved strip section; 802 is the cylindrical section; 9 is the insulating filling layer. Detailed Implementation
[0025] The core of this invention is to provide a semiconductor laser with built-in power monitoring. The structural design of this semiconductor laser with built-in power monitoring enables the simultaneous fabrication of the laser and detector during the manufacturing process, solving the problem of power monitoring in the later stage and reducing packaging costs.
[0026] 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.
[0027] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of a semiconductor laser with built-in power monitoring provided in an embodiment of the present invention. Figure 2 This is a top view of a semiconductor laser with built-in power monitoring provided in an embodiment of the present invention.
[0028] This invention discloses a semiconductor laser with built-in power monitoring, which includes a lower electrode layer 1, a substrate layer 2, a lower capping layer 3, a lower waveguide layer 4, a multiple quantum well layer 5, an upper waveguide layer 6, a laser ridge layer 7, a detector coupling layer 8, and an insulating filling layer 9.
[0029] The lower electrode layer 1, substrate layer 2, lower capping layer 3, lower waveguide layer 4, multiple quantum well layer 5, and upper waveguide layer 6 are stacked sequentially from bottom to top. The laser ridge layer 7, detector coupling layer 8, and insulating filling layer 9 are all disposed on the upper waveguide layer 6. The detector coupling layer 8 and the laser ridge layer 7 are arranged alternately. The insulating filling layer 9 partially encloses the laser ridge layer 7 and the detector coupling layer 8, exposing the first upper electrode layer at the upper end of the laser ridge layer 7 and the second upper electrode layer at the upper end of the detector coupling layer 8. The detector coupling layer 8 and the laser ridge layer 7 are electrically isolated and optically coupled. The lower electrode layer 1 serves as both the negative electrode of the laser and the positive electrode of the detector, meaning that the laser and the detector share the lower electrode layer 1. The first upper electrode layer serves as the positive electrode of the laser, through which the positive voltage terminal of the laser is applied. The second upper electrode layer serves as the negative electrode of the detector, through which the negative voltage terminal of the detector is applied.
[0030] Compared with the prior art, the semiconductor laser with built-in power monitoring provided in this embodiment of the invention simultaneously fabricates a laser ridge layer 7 and a detector coupling layer 8 on the upper waveguide layer 6 during the fabrication process, thereby achieving the purpose of power monitoring of the semiconductor laser without increasing manufacturing and packaging costs.
[0031] In one embodiment of this application, the laser ridge layer 7 includes a lower ridge layer, a middle ridge layer, and an upper ridge layer stacked sequentially from bottom to top. The lower ridge layer is an InP ridge lower layer or an InAlGaAs ridge lower layer that has undergone P-type modulation doping, with a P-type doping concentration of 4 × 10⁻⁶. 18 cm -3 Up to 9×10 18 cm -3 The ridge middle layer is an InGaAs ridge middle layer that has undergone p-type modulation doping. The ridge middle layer serves as the contact layer, and the p-type doping concentration is 1×10⁻⁶. 19 cm -3 Up to 2×10 19 cm -3 The upper layer of the ridge is the first upper electrode layer, which adopts a double-layer structure, including a first titanium layer and a first gold layer stacked from bottom to top. The laser current is injected from the first upper electrode layer.
[0032] Specifically, the laser ridge layer 7 has a dimension of 150μm to 4000μm along a first direction perpendicular to the stacking direction, and a dimension of 2μm to 100μm along a second direction perpendicular to the stacking direction. The first direction is perpendicular to the second direction. The laser ridge layer 7 has a dimension of 0.9μm to 1.2μm along the stacking direction. Among them, the dimension of the ridge middle layer along the stacking direction is 0.2μm to 0.4μm, the dimension of the first titanium layer along the stacking direction is 50nm to 100nm, and the dimension of the first gold layer along the stacking direction is not less than 300nm.
[0033] like Figure 1 and Figure 2 As shown, in one embodiment of this application, the detector coupling layer 8 includes a curved strip portion 801 and a cylindrical portion 802. The first end of the curved strip portion 801 is close to the laser ridge layer 7, and the second end of the curved strip portion 801 bends and extends away from the laser ridge layer 7. That is, the second end of the curved strip portion 801 extends along the length direction of the laser ridge layer 7, i.e., the first direction, while bending away from the laser ridge layer 7. The second end of the curved strip portion 801 is connected to the cylindrical portion 802.
[0034] Specifically, the dimension of the curved strip portion 801 along the first direction perpendicular to the stacking direction is 20μm~30μm, the dimension of the curved strip portion 801 along the second direction perpendicular to the stacking direction is 2μm~3μm, the minimum distance between the first end of the curved strip portion 801 and the laser ridge layer 7 is 1μm, the first direction is perpendicular to the second direction, the dimension of the curved strip portion 801 along the stacking direction is 0.9μm~1.2μm, the diameter of the cylindrical portion 802 is 50μm~60μm, and the dimension of the cylindrical portion 802 along the stacking direction is 0.9μm~1.2μm.
[0035] The detector coupling layer 8 comprises a lower coupling layer, a middle coupling layer, and an upper coupling layer stacked sequentially from bottom to top. The lower coupling layer is an InP coupling lower layer or an InAlGaAs coupling lower layer with P-type modulation doping, and the P-type doping concentration is 4 × 10⁻⁶. 18 cm -3 Up to 9×10 18 cm -3 The coupling middle layer, serving as the contact layer, is an InGaAs coupling middle layer with p-type modulation doping at a concentration of 1 × 10⁻⁶. 19 cm -3 Up to 2×10 19 cm -3 The dimensions along the stacking direction are 0.2μm to 0.4μm. The upper coupling layer is a second upper electrode layer, which includes a second titanium layer and a second gold layer stacked sequentially from bottom to top. The dimensions of the second titanium layer along the stacking direction are 50 nm to 100 nm, and the dimensions of the second gold layer along the stacking direction are not less than 300 nm.
[0036] As can be seen, in the embodiments of this application, the laser ridge layer 7 and the detector coupling layer 8 are specially designed and well isolated, which can achieve optical coupling of less than 1 / 100, thereby realizing power monitoring.
[0037] Preferably, in one embodiment of this application, the lower electrode layer 1 adopts a double-layer structure and has the following two configurations: one is that the lower electrode layer 1 includes a third gold layer and a third titanium layer stacked sequentially from bottom to top; the other is that the lower electrode layer 1 includes a third gold layer and a gold-germanium-nickel layer stacked sequentially from bottom to top. It should be noted that in this embodiment, the dimension of the third gold layer along the stacking direction is not less than 300 nm, the dimension of the third titanium layer or the gold-germanium-nickel layer along the stacking direction is not less than 40 nm, and the third gold layer, the third titanium layer or the gold-germanium-nickel layer must be flat and smooth.
[0038] The substrate layer 2 is located above the lower electrode layer 1, and the substrate layer 2 is either a GaAs substrate layer 2 or an InP substrate layer 2 that has undergone N-type modulation doping. The size of the substrate layer 2 along the stacking direction is 100μm~120μm.
[0039] The lower capping layer 3 is disposed on the substrate layer 2. The lower capping layer 3 is an InP lower capping layer 3 or an AlGaAs lower capping layer 3 with N-type modulation doping, and the N-type doping concentration is 2×10⁻⁶. 18 cm -3 The dimensions of the lower cover layer 3 along the stacking direction are not less than 1.6 μm.
[0040] The lower waveguide layer 4 is disposed above the lower capping layer 3. The lower waveguide layer 4 is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, and the unintentional doping concentration is less than 1×10⁻⁶. 17 cm -3 The dimension of the lower waveguide layer 4 along the stacking direction is not less than 0.5 μm. The refractive index of the lower waveguide layer 4 gradually increases from bottom to top, satisfying the e-exponential distribution, and the highest refractive index value does not exceed 3.55.
[0041] The multiple quantum well layer 5 is disposed above the lower waveguide layer 4. The multiple quantum well layer 5 is an InGaAs multiple quantum well layer 5 or an InGaAsP multiple quantum well layer 5, and the unintentional doping concentration is less than 1×10⁻⁶. 17 cm -3 The dimensions of the multiple quantum well layer 5 along the stacking direction are 10nm~120nm. The multiple quantum well layer 5 includes 1~9 quantum wells, the thickness of the well layer is 3nm~9nm, and the thickness of the barrier layer is 5nm~12nm.
[0042] Upper waveguide layer 6 is located above multiple quantum well layer 5. Upper waveguide layer 6 is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, with an unintentional doping concentration of less than 1×10⁻⁶. 17 cm -3 The size of the upper waveguide layer 6 along the stacking direction is not less than 0.9 μm. The refractive index of the upper waveguide layer 6 gradually decreases from bottom to top, satisfying a hyperbolic function distribution, and the minimum refractive index value is not less than 2.9.
[0043] An insulating filling layer 9 is disposed on the upper waveguide layer 6, and the insulating filling layer 9 is a silicon oxide layer or a silicon nitride layer.
[0044] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0045] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
Claims
1. A semiconductor laser with built-in power monitoring, characterized in that, The device comprises a lower electrode layer, a substrate layer, a lower capping layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, a laser ridge layer, a detector coupling layer, and an insulating filler layer. The lower electrode layer, the substrate layer, the lower capping layer, the lower waveguide layer, the multi-quantum well layer, and the upper waveguide layer are stacked sequentially from bottom to top. The laser ridge layer, the detector coupling layer, and the insulating filler layer are all disposed on the upper waveguide layer. The detector coupling layer is arranged at intervals from the laser ridge layer. The insulating filler layer partially encloses the laser ridge layer and the detector coupling layer, exposing the first upper electrode layer at the upper end of the laser ridge layer and the second upper electrode layer at the upper end of the detector coupling layer. The detector coupling layer is electrically isolated from the laser ridge layer and optically coupled. The detector coupling layer includes a curved strip portion and a cylindrical portion. The first end of the curved strip portion is close to the laser ridge layer, and the second end of the curved strip portion extends away from the laser ridge layer and is connected to the cylindrical portion. The detector coupling layer includes a lower coupling layer, a middle coupling layer, and a upper coupling layer stacked sequentially from bottom to top. The lower coupling layer is an InP coupling lower layer or an InAlGaAs coupling lower layer with P-type modulation doping. The middle coupling layer is an InGaAs coupling middle layer with P-type modulation doping. The upper coupling layer is a second upper electrode layer, which includes a second titanium layer and a second gold layer stacked sequentially from bottom to top.
2. The semiconductor laser with built-in power monitoring according to claim 1, characterized in that, The laser ridge layer comprises a lower ridge layer, a middle ridge layer, and an upper ridge layer stacked sequentially from bottom to top. The lower ridge layer is an InP ridge lower layer or an InAlGaAs ridge lower layer that has undergone P-type modulation doping. The middle ridge layer is an InGaAs ridge middle layer that has undergone P-type modulation doping. The upper ridge layer is the first upper electrode layer, which includes a first titanium layer and a first gold layer stacked sequentially from bottom to top.
3. The semiconductor laser with built-in power monitoring according to claim 2, characterized in that, The laser ridge layer has a dimension of 150μm to 4000μm along a first direction perpendicular to the stacking direction, and a dimension of 2μm to 100μm along a second direction perpendicular to the stacking direction. The first direction is perpendicular to the second direction, and the dimension of the laser ridge layer along the stacking direction is 0.9μm to 1.2μm.
4. The self-powered monitored semiconductor laser of claim 1, wherein, The curved strip portion has a dimension of 20μm to 30μm along a first direction perpendicular to the stacking direction, and the curved strip portion has a dimension of 2μm to 3μm along a second direction perpendicular to the stacking direction. The first direction is perpendicular to the second direction. The curved strip portion has a dimension of 0.9μm to 1.2μm along the stacking direction. The cylindrical portion has a diameter of 50μm to 60μm. The cylindrical portion has a dimension of 0.9μm to 1.2μm along the stacking direction.
5. The self-powered monitored semiconductor laser of any of claims 1-4, wherein, The lower electrode layer includes a third gold layer and a third titanium layer stacked sequentially from bottom to top, or the lower electrode layer includes a third gold layer and a gold-germanium-nickel layer stacked sequentially from bottom to top, wherein the dimension of the third gold layer along the stacking direction is not less than 300 nm, and the dimension of the third titanium layer or the gold-germanium-nickel layer along the stacking direction is not less than 40 nm.
6. The self-powered monitored semiconductor laser of any of claims 1-4, wherein, The substrate is an N-type modulated doped GaAs substrate or an InP substrate, and the size of the substrate along the stacking direction is 100μm~120μm.
7. The self-powered monitored semiconductor laser of any of claims 1-4, wherein the self-powered monitored semiconductor laser is a vertical cavity surface emitting laser (VCSEL). The lower capping layer is an InP lower capping layer or an AlGaAs lower capping layer that has undergone N-type modulation doping, and the dimension of the lower capping layer along the stacking direction is not less than 1.6 μm.
8. The semiconductor laser with built-in power monitoring according to any one of claims 1-4, characterized in that, The lower waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer. The dimension of the lower waveguide layer along the stacking direction is not less than 0.5 μm. The refractive index of the lower waveguide layer gradually increases from bottom to top, and the maximum refractive index value does not exceed 3.
55.
9. The semiconductor laser with built-in power monitoring according to any one of claims 1-4, characterized in that, The multiple quantum well layer is an InGaAs multiple quantum well layer or an InGaAsP multiple quantum well layer. The dimensions of the multiple quantum well layer along the stacking direction are 10nm to 120nm. The multiple quantum well layer includes 1 to 9 quantum wells, the thickness of the well layer is 3nm to 9nm, and the thickness of the barrier layer is 5nm to 12nm.
10. The semiconductor laser with built-in power monitoring according to any one of claims 1-4, characterized in that, The upper waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer. The size of the upper waveguide layer along the stacking direction is not less than 0.9 μm. The refractive index of the upper waveguide layer gradually decreases from bottom to top, and the minimum refractive index value is not less than 2.
9.
11. The self-powered monitored semiconductor laser of any of claims 1-4, wherein, The insulating filler layer is a silicon oxide layer or a silicon nitride layer.