Wide-wavelength electro-absorption modulated laser chip and preparation method and application thereof

Abstract

The invention relates to the technical field of laser chips, in particular to a wide-wavelength electro-absorption modulated laser chip and a preparation method and application thereof. According to the wide-wavelength electro-absorption modulated laser chip provided by the invention, a plurality of specific areas are divided on a substrate, a first modulator layer, a first front grating layer and a second modulator layer are sequentially arranged on the areas, and phosphorus ions are injected into the first modulator layer and the second modulator layer. The key sampling grating is arranged in the first front grating layer, the rear grating layer and the second front grating layer in an electron beam direct writing mode. A cladding layer and an electric contact layer are sequentially stacked above all the functional layers, an electric isolation trench is formed between the functional layers through etching, the uppermost layer is a P-surface electrode, and an N-surface electrode is arranged below the substrate. According to the chip, the same post-sampling grating reflection area is utilized, double-end modulation is integrated through the quantum well hybrid technology, the effects of double-end light emitting and rate and wavelength tuning performance doubling of the same integrated chip are achieved, and the power consumption of the integrated chip is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of laser chips, and in particular to a wide-wavelength electro-absorption modulated laser chip and a preparation method and application thereof. Background Art

[0002] With the rapid development of optical communications, people have higher and higher requirements on the bandwidth of optical transmitter chips. The bandwidth limit of optical transmitter chips is constantly being broken, but it is increasingly difficult to break through the bandwidth due to physical limitations. In order to improve the bandwidth of optical transmitter chips, on the one hand, multi-wavelength solutions are used, and on the other hand, the bandwidth is improved through modulation formats. The modulation format of optical transmitter chips has gradually developed from the past 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 extensive.

[0003] In order to meet the technical requirements of coherent and multi-wavelength light emission, it is urgently necessary to provide a wide-wavelength electro-absorption modulated laser chip. Summary of the invention

[0004] The purpose of the present invention is to propose a wide-wavelength electro-absorption modulated laser chip and its preparation method and application. The chip uses the same post-sampling grating reflection area and integrates double-end modulation through quantum well hybrid technology to achieve double-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 a light emission solution for coherent communication.

[0005] To this end, the present invention provides the following technical solutions:

[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 back grating layer, a second phase layer, a second gain layer, a second front grating layer, a second modulator layer, a sampling grating, a cladding, 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 arranged on both sides of the rear grating region, the first gain region and the second gain region are respectively arranged on a 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 arranged on a side of the first gain region and the second gain region away from the rear grating region, and the first modulator region and the second modulator region are respectively arranged on a 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 back grating layer, the second phase layer, the second gain layer, the second front grating layer and the second modulator layer are respectively arranged on the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region arranged on the substrate, and phosphorus ions are implanted into the first modulator layer and the second modulator layer;

[0009] The sampling grating is arranged 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 arranged above each functional layer from bottom to top;

[0011] The electrical isolation channels are arranged between the functional layers by etching;

[0012] The P-side electrode is arranged above each functional layer;

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

[0014] Preferably, the fluorescence wavelength of the passive material used in the first front grating layer, the first phase layer, the back grating layer, the second phase layer and the second front grating layer is 90-200nm shorter 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 they include a lower confinement layer, a multi-quantum well layer and an upper confinement layer from bottom to top. An inverted shallow ridge waveguide structure is also provided on the cladding layer and the electrical contact layer.

[0015] In the present invention, it is necessary to strictly limit 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 to be 90-200nm smaller than the emission wavelength of the laser chip. This is because if the fluorescence wavelength of the material in the grating region and the phase region is close to the emission wavelength of the laser, the light will be absorbed by the passive region material when it is transmitted in the passive region, and the oscillation enhancement effect of the light in the resonant cavity cannot be formed. Therefore, the fluorescence wavelength of the passive material is longer than the emission wavelength of the laser. In addition, the inverted shallow ridge waveguide structure is a waveguide with a shape that is wide on the top and narrow on the bottom. It is determined by the crystal structure of the cladding InP material itself and is corroded by hydrochloric acid etching solution to form an inverted structure naturally formed. The so-called shallow ridge waveguide means that the ridge waveguide has not been etched through the quantum well layer.

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

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

[0018] S1: growing active materials of a lower confinement layer, a multi-quantum well layer and an upper confinement layer in sequence on the surface of a substrate, and arranging a first modulator region, a first front grating region, a first gain region, a first phase region, a back grating region, a second phase region, a second gain region, a second front grating region and a second modulator region on the substrate;

[0019] S2: Covering 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 removing the active material of the lower confinement layer, the multi-quantum well layer and the upper confinement layer of the first front grating region, the first phase region, the back grating region, the second phase region and the second front grating region by etching technology;

[0020] S3: growing passive materials at 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: manufacturing sampling gratings in the first front grating region, the rear grating region and the second front grating region by electron beam direct writing technology, and then covering the second mask on the other regions except the first modulator region and the second modulator region, and finally implanting phosphorus ions into the active materials of the lower confinement layer, the multi-quantum well layer and the upper confinement layer in the first modulator region and the second modulator region, and performing annealing after the implantation;

[0022] S5: A cladding layer and an electrical contact layer are sequentially grown above the active material and the passive material of each functional region, and an inverted shallow ridge waveguide structure is arranged on the cladding layer and the electrical contact layer. Then, an electrical isolation groove is etched on the electrical contact layer to electrically isolate each functional region. Finally, a P-side electrode is arranged on the electrical contact layer of each functional region, and an N-side electrode is arranged under the substrate.

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

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

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

[0026] The chip provided by the present invention utilizes the same post-sampling grating reflection area and integrates double-end modulation through quantum well hybrid technology to achieve double-end light output from the same integrated chip, doubling the rate and wavelength tuning performance, and greatly reducing the power consumption of the integrated chip. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

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

[0034] 1-first modulator region; 2-first front grating region; 3-first gain region; 4-first phase region; 5-back 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-electrical isolation groove; 22-P-side electrode; 23-N-side electrode. DETAILED DESCRIPTION

[0035] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

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

[0037] The technical solution of the present invention will be described in detail below in conjunction with embodiments and drawings.

[0038] Example 1

[0039] See also 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 back 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 19, an electrical contact layer 20, an electrical isolation groove 21, a P-surface electrode 22, and an N-surface 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 arranged on the substrate, the first phase region 4 and the second phase region 6 are arranged on both sides of the rear grating region 5, the first gain region 3 and the second gain region 7 are arranged on a 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 arranged on a side of the first gain region 3 and the second gain region 7 away from the rear grating region 5, and the first modulator region 1 and the second modulator region 9 are arranged on a side of the first front grating region 2 and the second front grating region 8 away from the rear grating region 5;

[0041] The first modulator layer, the first front grating layer, the first gain layer, the first phase layer, the back grating layer, the second phase layer, the second gain layer, the second front grating layer and the second modulator layer are respectively arranged on the first modulator region 1, the first front grating region 2, the first gain region 3, the first phase region 4, the back grating region 5, the second phase region 6, the second gain region 7, the second front grating region 8 and the second modulator region 9 arranged on the substrate, and phosphorus ions are implanted into the first modulator layer and the second modulator layer;

[0042] The sampling grating 17 is arranged in the first front grating layer, the rear grating layer and the second front grating layer by electron beam direct writing; the cladding 19 and the electrical contact layer 20 are arranged on each functional layer from bottom to top; the electrical isolation groove 21 is arranged between each functional layer by etching; the P-side electrode 22 is arranged on the top of each functional layer; and the N-side electrode 23 is arranged 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 90-200nm 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 a lower confinement layer 12, a multi-quantum well layer 13 and an upper confinement layer 14 from bottom to top.

[0043] In the present 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 oscillated light is strong enough, laser will be emitted from the end face.

[0044] Example 2

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

[0046] S1: Active materials of a lower confinement layer 12, a multi-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 multi-quantum well layer uses an InGaAsP active material with a fluorescence wavelength of 1500 nm, and the lower confinement layer and the upper confinement layer use an InGaAsP active material with a fluorescence wavelength of 1200 nm), and the substrate 11 is divided into a first modulator region 1, a first front grating region 2, a first gain region 3, a first phase region 4, a back 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, see Figure 1 ;

[0047] S2: The active material surface of the upper confinement layer in the first modulator region 1, the first gain region 3, the second gain region 7 and the second modulator region 9 is covered with a first silicon dioxide mask 15, and the active material of the lower confinement layer 12, the multi-quantum well layer 13 and the upper confinement layer 14 of the first front grating region 2, the first phase region 4, the back grating region 5, the second phase region 6 and the second front grating region 8 is removed by etching technology, see Figure 2 ;

[0048] S3: a passive material (InGaAsP passive material, whose fluorescence wavelength is 90-200nm smaller than the emission wavelength of the laser chip) is grown in a butt joint manner on 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 Figure 3 ;

[0049] S4: a sampling grating 17 is fabricated in the first front grating region 2, the rear grating region 5 and the second front grating region 8 by electron beam direct writing technology, and then a second silicon dioxide mask 18 is covered on the other regions except the first modulator region and the second modulator region, and finally phosphorus ions are implanted into the active materials of the lower confinement layer 12, the multi-quantum well layer 13 and the upper confinement layer 14 of the first modulator region 1 and the second modulator region 9, and annealing is performed at 600° C. for 200 seconds after the implantation is completed, see Figure 4 ;

[0050] S5: A cladding layer 19 and an electric contact layer 20 are sequentially grown on the active material and the passive material of each functional region (the material of the cladding layer is InP, and the material has P-type doping Zn, and the material of the electric contact layer is InGaAs, and the material has P-type doping Zn), and an inverted shallow ridge waveguide structure is arranged on the cladding layer 19 and the electric contact layer 20, and then an electric isolation groove 21 is etched on the electric contact layer 20 to achieve electrical isolation of each functional region, and finally a P-side electrode 22 is arranged on the electric contact layer of each functional region, and an N-side electrode 23 is arranged below the substrate, see Figure 5 .

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

Claims

1. A wide wavelength electro-absorption modulated laser chip, characterized in that: The device comprises a substrate, a first modulator layer, a first front grating layer, a first gain layer, a first phase layer, a back 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 arranged on both sides of the rear grating region, the first gain region and the second gain region are respectively arranged on a 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 arranged on a side of the first gain region and the second gain region away from the rear grating region, and the first modulator region and the second modulator region are respectively arranged on a 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 back grating layer, the second phase layer, the second gain layer, the second front grating layer and the second modulator layer are respectively arranged on the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region arranged on the substrate, and phosphorus ions are implanted into the first modulator layer and the second modulator layer; The sampling grating is arranged 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 arranged above each functional layer from bottom to top; The electrical isolation channels are arranged between the functional layers by etching; The P-side electrode is arranged above each functional layer; The N-side electrode is arranged 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 back grating layer, the second phase layer and the second front grating layer is 90-200 nm shorter 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 include a lower confinement layer, a multi-quantum well layer and an upper confinement layer from bottom to top.

4. The wide wavelength electro-absorption modulated laser chip according to claim 1, characterized in that: An inverted shallow ridge waveguide structure is also arranged on the cladding layer and the electric contact layer.

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

6. A method for preparing a wide-wavelength electro-absorption modulated laser chip, characterized in that: The following steps are involved: S1: growing active materials of a lower confinement layer, a multi-quantum well layer and an upper confinement layer in sequence on the surface of a substrate, and arranging a first modulator region, a first front grating region, a first gain region, a first phase region, a back grating region, a second phase region, a second gain region, a second front grating region and a second modulator region on the substrate; S2: Covering 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 removing the active material of the lower confinement layer, the multi-quantum well layer and the upper confinement layer of the first front grating region, the first phase region, the back grating region, the second phase region and the second front grating region by etching technology; S3: growing passive materials at the first front grating region, the first phase region, the rear grating region, the second phase region and the second front grating region; S4: manufacturing sampling gratings in the first front grating region, the rear grating region and the second front grating region by electron beam direct writing technology, and then covering the second mask on the other regions except the first modulator region and the second modulator region, and finally implanting phosphorus ions into the active materials of the lower confinement layer, the multi-quantum well layer and the upper confinement layer in the first modulator region and the second modulator region, and performing annealing after the implantation; S5: A cladding layer and an electrical contact layer are sequentially grown above the active material and the passive material of each functional region, and an inverted shallow ridge waveguide structure is arranged on the cladding layer and the electrical contact layer. Then, an electrical isolation groove is etched on the electrical contact layer to electrically isolate each functional region. Finally, a P-side electrode is arranged on the electrical contact layer of each functional region, and an N-side electrode is arranged under the substrate.

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

8. The method for preparing a wide-wavelength electro-absorption modulated laser chip according to claim 6, characterized in that: In step S1, the active material of the lower confinement layer, the multi-quantum well layer and the upper confinement layer is selected from one of InGaAsP and InGaAlAs.

9. The method for preparing 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 and InGaAlAs.

10. A wide wavelength electro-absorption modulated laser, characterized in that: It comprises the wide wavelength electro-absorption modulated laser chip as claimed in claim 1.

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