A wide-wavelength electroabsorption modulated laser chip, its fabrication method and application

Abstract

This invention relates to the field of laser chip technology, specifically to a wide-wavelength electro-absorption modulated laser chip, its fabrication method, and its applications. The wide-wavelength electro-absorption modulated laser chip provided by this invention divides a substrate into multiple specific regions. A first modulator layer, a first front grating layer, and a second modulator layer are sequentially disposed in these regions, with phosphorus ions implanted into the first and second modulator layers. The crucial sampling grating is placed within the first front grating layer, the rear grating layer, and the second front grating layer using electron beam direct writing. A cladding layer and an electrical contact layer are sequentially stacked above all functional layers. Electrical isolation trenches are formed between the functional layers through etching. The topmost layer is a P-side electrode, and an N-side electrode is located below the substrate. This chip utilizes the same rear sampling grating reflection region and integrates dual-end modulation through quantum well hybridization technology, achieving dual-end light output from the same integrated chip, doubling the rate and wavelength tuning performance, and significantly reducing the power consumption of the integrated chip.

Description

Technical Field

[0001] This invention relates to the field of laser chip technology, specifically to a wide-wavelength electroabsorption modulated laser chip, its fabrication method, and its applications. Background Technology

[0002] With the rapid development of optical communication, people have increasingly higher requirements for the bandwidth of optical transmitter chips. The bandwidth limit of optical transmitter chips is constantly being broken. However, due to physical limitations, the difficulty of breaking through the bandwidth limit is increasing. In order to improve the bandwidth of optical transmitter chips, on the one hand, multi-wavelength schemes are used, and on the other hand, modulation formats are used to improve the bandwidth. The modulation format of optical transmitter chips has gradually developed from intensity modulation to coherent modulation. Especially in recent years, coherent modulation has been used more and more in backbone networks and data centers. At the same time, the application of coherent modulation in the field of silicon photonics is also becoming more and more widespread.

[0003] To meet the technical requirements of coherent and multi-wavelength light emission, there is an urgent need to provide a wide-wavelength electro-absorption modulated laser chip. Summary of the Invention

[0004] The purpose of this invention is to propose a wide-wavelength electro-absorption modulation laser chip, its fabrication method, and its application. This chip utilizes the same post-sampling grating reflection region and integrates dual-end modulation through quantum well hybridization technology to achieve dual-end light output from the same integrated chip, doubling the rate and wavelength tuning performance, greatly reducing the power consumption of the integrated chip, and providing an optical emission solution for coherent communication.

[0005] Therefore, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a wide-wavelength electro-absorption modulated laser chip in an optional embodiment, comprising a substrate, a first modulator layer, a first front grating layer, a first gain layer, a first phase layer, a rear grating layer, a second phase layer, a second gain layer, a second front grating layer, a second modulator layer, a sampling grating, a cladding layer, an electrical contact layer, an electrical isolation trench, a P-side electrode, and an N-side electrode.

[0007] The substrate is provided with a first modulator region, a first front grating region, a first gain region, a first phase region, a rear grating region, a second phase region, a second gain region, a second front grating region, and a second modulator region. The first phase region and the second phase region are respectively disposed on both sides of the rear grating region. The first gain region and the second gain region are respectively disposed on the side of the first phase region and the second phase region away from the rear grating region. The first front grating region and the second front grating region are respectively disposed on the side of the first gain region and the second gain region away from the rear grating region. The first modulator region and the second modulator region are respectively disposed on the side of the first front grating region and the second front grating region away from the rear grating region.

[0008] The first modulator layer, the first front grating layer, the first gain layer, the first phase layer, the rear grating layer, the second phase layer, the second gain layer, the second front grating layer, and the second modulator layer are respectively disposed on the first modulator region, the first front grating region, the first gain region, the first phase region, the rear grating region, the second phase region, the second gain region, the second front grating region, and the second modulator region disposed on the substrate, and phosphorus ions are implanted in the first modulator layer and the second modulator layer;

[0009] The sampling grating is disposed in the first front grating layer, the rear grating layer, and the second front grating layer by electron beam direct writing;

[0010] The cladding layer and the electrical contact layer are sequentially disposed above each functional layer from bottom to top;

[0011] The electrical isolation communication is set between each functional layer through etching.

[0012] The P-side electrodes are positioned above each functional layer;

[0013] The N-side electrode is disposed below the substrate.

[0014] Preferably, the fluorescence wavelength of the passive materials used in the first front grating layer, first phase layer, rear grating layer, second phase layer, and second front grating layer is 90-200 nm smaller than the emission wavelength of the laser chip. The active materials used in the first modulator layer, first gain layer, second gain layer, and second modulator layer are the same, and they sequentially include a lower confinement layer, a multiple quantum well layer, and an upper confinement layer from bottom to top. A truncated shallow ridge waveguide structure is also disposed on the cladding and electrical contact layer.

[0015] In this invention, it is necessary to strictly limit the fluorescence wavelength of the passive materials used in the first front grating layer, first phase layer, rear grating layer, second phase layer, and second front grating layer to be 90-200 nm smaller than the emission wavelength of the laser chip. This is because if the fluorescence wavelength of the materials in the grating region and phase region is similar to the emission wavelength of the laser, the light will be absorbed by the passive region material during transmission, failing to form an oscillation enhancement effect in the resonant cavity. Therefore, the fluorescence wavelength of the passive material must be longer than the emission wavelength of the laser. Furthermore, the inverted shallow ridge waveguide mechanism is a waveguide shape that is wider at the top and narrower at the bottom, determined by the crystal structure of the cladding InP material itself. It is formed naturally through etching with hydrochloric acid. The term "shallow ridge waveguide" indicates that the quantum well layer has not been etched into the ridge waveguide.

[0016] Preferably, the wavelength tuning range of the wide-wavelength electroabsorption modulated laser chip is greater than 40nm and can be continuously tuned.

[0017] Secondly, in an optional embodiment, the present invention provides a method for fabricating a wide-wavelength electro-absorption modulated laser chip, comprising the following steps:

[0018] S1: Active materials of a lower confinement layer, a multiple quantum well layer and an upper confinement layer are sequentially grown on the surface of a substrate, and a first modulator region, a first front grating region, a first gain region, a first phase region, a rear grating region, a second phase region, a second gain region, a second front grating region and a second modulator region are formed on the substrate.

[0019] S2: Cover the active material surface of the upper confinement layer of the first modulator region, the first gain region, the second gain region and the second modulator region with a first mask, and use etching technology to remove the active material of the lower confinement layer, the multiple quantum well layer and the upper confinement layer of the first front grating region, the first phase region, the rear grating region, the second phase region and the second front grating region;

[0020] S3: Passive materials are grown by docking the first front grating region, the first phase region, the rear grating region, the second phase region, and the second front grating region;

[0021] S4: A sampling grating is fabricated in the first front grating region, the rear grating region, and the second front grating region using electron beam direct writing technology. Then, a second mask is covered on the other regions except for the first modulator region and the second modulator region. Finally, phosphorus ions are implanted into the active materials of the lower confinement layer, the multiple quantum well layer, and the upper confinement layer of the first modulator region and the second modulator region. After implantation, annealing is performed.

[0022] S5: A cladding layer and an electrical contact layer are grown sequentially above the active and passive materials of each functional region. A truncated shallow ridge waveguide structure is set on the cladding layer and the electrical contact layer. Then, an electrical isolation trench is etched on the electrical contact layer to achieve electrical isolation between each functional region. Finally, a P-side electrode is set on the electrical contact layer of each functional region, and an N-side electrode is set below the substrate.

[0023] Preferably, in step S4, the annealing time is 180-220 s; the annealing temperature is 580-620 °C. In step S1, the active materials of the lower confinement layer, the multiple quantum well layer, and the upper confinement layer are selected from InGaAsP or InGaAlAs. In step S3, the passive material is selected from one or more of InGaAsP or InGaAlAs.

[0024] The third invention provides a wide-wavelength electro-absorption modulated laser in an optional embodiment, comprising the wide-wavelength electro-absorption modulated laser chip described above.

[0025] Compared with the prior art, the present invention has one of the following beneficial effects:

[0026] The chip provided by this invention utilizes the same post-sampling grating reflection area and integrates dual-end modulation through quantum well hybrid technology to achieve dual-end light output from the same integrated chip, doubling the speed and wavelength tuning performance, and greatly reducing the power consumption of the integrated chip. Attached Figure Description

[0027] The advantages of the above and / or additional aspects of this application will become apparent and readily understood in the description of the embodiments in conjunction with the following drawings, wherein:

[0028] Figure 1 This is a side view of the chip structure in step S1 of embodiment 2 of the present invention;

[0029] Figure 2 This is a side view of the chip structure in step S2 of embodiment 2 of the present invention;

[0030] Figure 3 This is a side view of the chip structure in step S3 of embodiment 2 of the present invention;

[0031] Figure 4 This is a side view of the chip structure in step S4 of embodiment 2 of the present invention;

[0032] Figure 5 This is a side view of the wide-wavelength electro-absorption modulated laser chip structure in Embodiments 1 and 2 of the present invention;

[0033] Figure 6 This is a cross-sectional view of the wide-wavelength electro-absorption modulated laser chip structure in Embodiment 1 of the present invention.

[0034] 1-First modulator region; 2-First front grating region; 3-First gain region; 4-First phase region; 5-Rear grating region; 6-Second phase region; 7-Second gain region; 8-Second front grating region; 9-Second modulator region; 11-Substrate; 12-Lower confinement layer; 13-Multiple quantum well layer; 14-Upper confinement layer; 15-First mask; 16-Passive material; 17-Sampling grating; 18-Second mask; 19-Cladding; 20-Electrical contact layer; 21-Electrically isolated trench; 22-P-side electrode; 23-N-side electrode. Detailed Implementation

[0035] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

[0036] In the following description, many specific details are set forth in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0037] The technical solution of the present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0038] Example 1

[0039] See Figure 5 and Figure 6 This embodiment provides a wide-wavelength electro-absorption modulated laser chip, including a substrate 11, a first modulator layer, a first front grating layer, a first gain layer, a first phase layer, a rear grating layer, a second phase layer, a second gain layer, a second front grating layer, a second modulator layer, a sampling grating 17, a cladding layer 19, an electrical contact layer 20, an electrical isolation trench 21, a P-side electrode 22, and an N-side electrode 23;

[0040] A first modulator region 1, a first front grating region 2, a first gain region 3, a first phase region 4, a rear grating region 5, a second phase region 6, a second gain region 7, a second front grating region 8, and a second modulator region 9 are disposed on the substrate. The first phase region 4 and the second phase region 6 are respectively disposed on both sides of the rear grating region 5. The first gain region 3 and the second gain region 7 are respectively disposed on the side of the first phase region 4 and the second phase region 6 away from the rear grating region 5. The first front grating region 2 and the second front grating region 8 are respectively disposed on the side of the first gain region 3 and the second gain region 7 away from the rear grating region 5. The first modulator region 1 and the second modulator region 9 are respectively disposed on the side of the first front grating region 2 and the second front grating region 8 away from the rear grating region 5.

[0041] A first modulator layer, a first front grating layer, a first gain layer, a first phase layer, a rear grating layer, a second phase layer, a second gain layer, a second front grating layer, and a second modulator layer are respectively disposed on a first modulator region 1, a first front grating region 2, a first gain region 3, a first phase region 4, a rear grating region 5, a second phase region 6, a second gain region 7, a second front grating region 8, and a second modulator region 9 disposed on a substrate, and phosphorus ions are implanted in the first modulator layer and the second modulator layer;

[0042] The sampling grating 17 is disposed in the first front grating layer, the rear grating layer, and the second front grating layer by direct electron beam writing; the cladding layer 19 and the electrical contact layer 20 are disposed above each functional layer from bottom to top; the electrical isolation trench 21 is disposed between each functional layer by etching; the P-side electrode 22 is disposed above each functional layer; and the N-side electrode 23 is disposed below the substrate 11. The fluorescence wavelength of the passive material used in the first front grating layer, the first phase layer, the rear grating layer, the second phase layer, and the second front grating layer is 90-200 nm smaller than the emission wavelength of the laser chip. The active material used in the first modulator layer, the first gain layer, the second gain layer, and the second modulator layer is the same, and it includes, from bottom to top, a lower confinement layer 12, a multiple quantum well layer 13, and an upper confinement layer 14.

[0043] In this invention, applying current to the first gain region 3 and the second gain region 7 can generate light. The generated light oscillates in the resonant cavity formed by the first front grating region 2, the rear grating region 5 and the second front grating region 8. When the light generated by the oscillation is strong enough, laser light will be emitted from the end face.

[0044] Example 2

[0045] See Figure 1-Figure 5 This embodiment provides a method for fabricating a wide-wavelength electro-absorption modulated laser chip, including the following steps:

[0046] S1: Active materials for a lower confinement layer 12, a multiple quantum well layer 13, and an upper confinement layer 14 are sequentially grown on the surface of an N-type indium phosphide substrate 11 (the multiple quantum well layer uses InGaAsP active material with a fluorescence wavelength of 1500nm, and the lower and upper confinement layers use InGaAsP active material with a fluorescence wavelength of 1200nm). A first modulator region 1, a first front grating region 2, a first gain region 3, a first phase region 4, a rear grating region 5, a second phase region 6, a second gain region 7, a second front grating region 8, and a second modulator region 9 are defined on the substrate 11. (See [reference]). Figure 1 ;

[0047] S2: A silicon dioxide first mask 15 is applied to the surface of the active material in the upper confinement layer of the first modulator region 1, the first gain region 3, the second gain region 7, and the second modulator region 9. The active material in the lower confinement layer 12, the multiple quantum well layer 13, and the upper confinement layer 14 of the first front grating region 2, the first phase region 4, the rear grating region 5, the second phase region 6, and the second front grating region 8 is removed using etching techniques. (See [link to documentation]). Figure 2 ;

[0048] S3: A passive material (InGaAsP passive material, whose fluorescence wavelength is 90-200 nm smaller than the emission wavelength of the laser chip) is grown by mating the first front grating region 2, the first phase region 3, the rear grating region 4, the second phase region 6, and the second front grating region 8. See [link / reference]. Figure 3 ;

[0049] S4: A sampling grating 17 is fabricated using electron beam direct writing technology in the first front grating region 2, the rear grating region 5, and the second front grating region 8. Then, a second silicon dioxide mask 18 is deposited on the regions other than the first and second modulator regions. Finally, phosphorus ions are implanted into the active materials of the lower confinement layer 12, the multiple quantum well layer 13, and the upper confinement layer 14 of the first and second modulator regions 1 and 9. After implantation, annealing is performed at 600°C for 200 seconds. See [link to documentation]. Figure 4 ;

[0050] S5: A cladding layer 19 and an electrical contact layer 20 are sequentially grown above the active and passive materials of each functional region (the cladding layer is made of InP with P-type doped Zn, and the electrical contact layer is made of InGaAs with P-type doped Zn). A truncated shallow ridge waveguide structure is then formed on the cladding layer 19 and the electrical contact layer 20. An electrical isolation trench 21 is then etched on the electrical contact layer 20 to achieve electrical isolation between the functional regions. Finally, a P-side electrode 22 is formed on the electrical contact layer of each functional region, and an N-side electrode 23 is formed below the substrate. See [link to documentation]. Figure 5 .

[0051] Although this application has been disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and not intended to limit the application of this application. The scope of protection of this application is defined by the appended claims and may include various variations, modifications, and equivalents of the invention without departing from the scope and spirit of this application.

Claims

1. A wide-wavelength electroabsorption modulated laser chip, characterized in that, It includes a substrate, a first modulator layer, a first front grating layer, a first gain layer, a first phase layer, a rear grating layer, a second phase layer, a second gain layer, a second front grating layer, a second modulator layer, a sampling grating, a cladding layer, an electrical contact layer, an electrical isolation trench, a P-side electrode, and an N-side electrode; The substrate is provided with a first modulator region, a first front grating region, a first gain region, a first phase region, a rear grating region, a second phase region, a second gain region, a second front grating region, and a second modulator region. The first phase region and the second phase region are respectively disposed on both sides of the rear grating region. The first gain region and the second gain region are respectively disposed on the side of the first phase region and the second phase region away from the rear grating region. The first front grating region and the second front grating region are respectively disposed on the side of the first gain region and the second gain region away from the rear grating region. The first modulator region and the second modulator region are respectively disposed on the side of the first front grating region and the second front grating region away from the rear grating region. The first modulator layer, the first front grating layer, the first gain layer, the first phase layer, the rear grating layer, the second phase layer, the second gain layer, the second front grating layer, and the second modulator layer are respectively disposed on the first modulator region, the first front grating region, the first gain region, the first phase region, the rear grating region, the second phase region, the second gain region, the second front grating region, and the second modulator region disposed on the substrate, and phosphorus ions are implanted in the first modulator layer and the second modulator layer; The sampling grating is disposed in the first front grating layer, the rear grating layer, and the second front grating layer by electron beam direct writing; The cladding layer and the electrical contact layer are sequentially disposed above each functional layer from bottom to top; The electrical isolation communication is set between each functional layer through etching. The P-side electrodes are positioned above each functional layer; The N-side electrode is disposed below the substrate.

2. The wide-wavelength electro-absorption modulated laser chip according to claim 1, characterized in that, The fluorescence wavelength of the passive materials used in the first front grating layer, the first phase layer, the rear grating layer, the second phase layer, and the second front grating layer is 90-200 nm smaller than the emission wavelength of the laser chip.

3. The wide-wavelength electro-absorption modulated laser chip according to claim 1, characterized in that, The first modulator layer, the first gain layer, the second gain layer, and the second modulator layer use the same active material, and from bottom to top, they include a lower confinement layer, a multiple quantum well layer, and an upper confinement layer.

4. The wide-wavelength electro-absorption modulated laser chip according to claim 1, characterized in that, The cladding and electrical contact layer are also provided with an inverted shallow ridge waveguide structure.

5. The wide-wavelength electro-absorption modulated laser chip according to claim 1, characterized in that, The wide-wavelength electroabsorption modulated laser chip has a wavelength tuning range greater than 40nm and can be continuously tuned.

6. A method for fabricating a wide-wavelength electroabsorption modulated laser chip, characterized in that, Includes the following steps: S1: Active materials of a lower confinement layer, a multiple quantum well layer and an upper confinement layer are sequentially grown on the surface of a substrate, and a first modulator region, a first front grating region, a first gain region, a first phase region, a rear grating region, a second phase region, a second gain region, a second front grating region and a second modulator region are formed on the substrate. S2: Cover the active material surface of the upper confinement layer of the first modulator region, the first gain region, the second gain region and the second modulator region with a first mask, and use etching technology to remove the active material of the lower confinement layer, the multiple quantum well layer and the upper confinement layer of the first front grating region, the first phase region, the rear grating region, the second phase region and the second front grating region; S3: Passive materials are grown by docking the first front grating region, the first phase region, the rear grating region, the second phase region, and the second front grating region; S4: A sampling grating is fabricated in the first front grating region, the rear grating region, and the second front grating region using electron beam direct writing technology. Then, a second mask is covered on the other regions except for the first modulator region and the second modulator region. Finally, phosphorus ions are implanted into the active materials of the lower confinement layer, the multiple quantum well layer, and the upper confinement layer of the first modulator region and the second modulator region. After implantation, annealing is performed. S5: A cladding layer and an electrical contact layer are grown sequentially above the active and passive materials of each functional region. A truncated shallow ridge waveguide structure is set on the cladding layer and the electrical contact layer. Then, an electrical isolation trench is etched on the electrical contact layer to achieve electrical isolation between each functional region. Finally, a P-side electrode is set on the electrical contact layer of each functional region, and an N-side electrode is set below the substrate.

7. The method for fabricating a wide-wavelength electro-absorption modulated laser chip according to claim 6, characterized in that, In step S4, the annealing time is 180-220 seconds; The annealing temperature is 580-620℃.

8. The method for fabricating a wide-wavelength electro-absorption modulated laser chip according to claim 6, characterized in that, In step S1, the active materials of the lower confinement layer, the multiple quantum well layer, and the upper confinement layer are selected from either InGaAsP or InGaAlAs.

9. The method for fabricating a wide-wavelength electro-absorption modulated laser chip according to claim 6, characterized in that, In step S3, the passive material is selected from one or more of InGaAsP or InGaAlAs.

10. A wide-wavelength electroabsorption modulated laser, characterized in that, Includes the wide-wavelength electroabsorption modulated laser chip as described in claim 1.

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