A high-power U-band multi-wavelength high-speed laser chip integrated on a chip

Abstract

The application discloses a kind of high-power U-band multi-wavelength high-speed laser chips integrated on chip, it is related to chip processing technical field, specifically including P-Si substrate, epitaxial transition buffer layer, buffer layer structure, laser gain region and waveguide structure, grating structure area, ridge waveguide structure, the high-power U-band multi-wavelength high-speed laser chip integrated on chip, through single piece realizes multi-wavelength high-speed laser, and beam combining and amplification, different oblique waveguide is used to different grating period and light wavelength, multiple target wavelengths can be realized on single piece by calculation, by reasonably setting ridge waveguide inclination angle, four wavelengths of 1621nm, 1641nm, 1661nm, 1681nm can be output simultaneously by laser, its performance can realize 100G long distance transmission, replace traditional discrete optical device;Epitaxial P-type substrate and coplanar electrode are used to effectively reduce device series resistance and heat dissipation power consumption, and the high-speed laser of multi-path beam combining is further amplified by SOA.

Description

Technical Field

[0001] This invention relates to the field of laser chip processing technology, specifically to an on-chip integrated high-power U-band multi-wavelength high-speed laser chip. Background Technology

[0002] With the increasing demand for information capacity, optical fiber resources are gradually expanding into the U-band of optical communication. High-speed optical communication devices generally use multiple discrete devices combined into a single high-speed output. However, since each device needs to be independently packaged, the final device is large in size, consumes a lot of power, and is expensive. The development of on-chip integration and co-packaged optics has led to the development of traditional discrete devices towards higher integration. Currently, high-speed optical submarines still use multiple external laser sources, which are bundled and packaged. Therefore, we propose an on-chip integrated high-power U-band multi-wavelength high-speed laser chip. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an on-chip integrated high-power U-band multi-wavelength high-speed laser chip, which solves the problems mentioned in the background section.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: an on-chip integrated high-power U-band multi-wavelength high-speed laser chip, comprising a P-Si substrate, an epitaxial transition buffer layer, a buffer layer structure, a laser gain region and waveguide structure, a grating structure region, and a ridge waveguide structure.

[0005] The epitaxial transition buffer layer mainly includes: a P-GaP buffer layer and a P-GaAs buffer layer;

[0006] The buffer layer structure mainly includes: a P-InP first buffer layer, a P-InGaAsP / P-InP multilayer superlattice structure, and a P-InP second buffer layer;

[0007] The laser gain region and waveguide structure along the growth direction mainly include: P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, and N-InAlAs electron blocking layer.

[0008] The grating structure region mainly includes: N-InP space layer, N-InGaAsP corrosion inhibitor layer, N-InP spacer layer, N-InGaAsP grating layer, and N-InP capping layer;

[0009] The ridge waveguide structure mainly includes: an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer, and an N-InP capping layer.

[0010] It also includes the following preparation methods;

[0011] S1: On a P-Si substrate, a P-GaP buffer layer, a P-GaAs buffer layer, and a P-InP first buffer layer are grown first by MOCVD to effectively reduce lattice mismatch.

[0012] S2: The substrate dislocations are effectively filtered by growing a lattice-matched InGaAsP-InP multilayer superlattice structure, and a second P-InP buffer layer is grown.

[0013] S3: Next, grow the laser gain region and waveguide structure: along the growth direction, sequentially generate the P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, and N-InAlAs electron blocking layer, and then continue to generate the InGaAsP etching blocking layer and beam layer, etc., to complete the substrate growth.

[0014] S4: A uniform grating is prepared in the laser region by holographic exposure and wet etching. Finally, an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer, and an N-InP capping layer are grown to complete the epitaxial growth.

[0015] S5: Next, laser and amplifier waveguides are fabricated by photolithography, etching and corrosion. The laser has multiple waveguides with different tilt angles, corresponding to different output target wavelengths. Lasers of different wavelengths are combined and input to the semiconductor optical amplifier chip.

[0016] S6: Electrical isolation between the laser and the amplifier is achieved by ion implantation; a P-type ohmic contact region is formed by photolithography, etching and corrosion, with the corrosion depth reaching the P-InP second buffer layer;

[0017] S7: Next, a SiO2 passivation layer is deposited, and a hole is opened at the top of the ridge waveguide and the P-type ohmic contact area to form a metal contact area. The Ti / Pt / Au metal is evaporated by electron beam, and the alloy forms P-type and N-type ohmic contacts.

[0018] S8: Finally, the chip fabrication is completed by dissociation, laser light emission, and deposition of high-transmittance and high-reflectance optical films on the backlight end face.

[0019] This invention provides an on-chip integrated high-power U-band multi-wavelength high-speed laser chip, which has the following advantages:

[0020] 1. This on-chip high-power U-band multi-wavelength high-speed laser chip achieves multi-wavelength high-speed laser beam combining and amplification on a single chip. Different tilted waveguides correspond to different grating periods and output wavelengths. Through calculation, multiple target wavelengths can be achieved on a single chip. By appropriately setting the ridge waveguide tilt angle, the laser can simultaneously output four wavelengths: 1621nm, 1641nm, 1661nm, and 1681nm. Its performance enables 100G long-distance transmission, replacing traditional discrete optical devices. The use of an epitaxial P-type substrate and coplanar electrodes effectively reduces the device's series resistance and heat dissipation. SOA further amplifies the multi-beam combined high-speed laser. The product features low power consumption, on-chip integration, and multi-wavelength beam combining high-speed output. Its performance meets the requirements of long-distance high-speed communication, enabling it to replace traditional high-speed optical devices. It is also compatible with silicon-based optoelectronic integration and is suitable for long-distance high-speed optical communication and data center applications. Attached Figure Description

[0021] Figure 1 The diagram shows the chip end face structure, where 1 is the epitaxial transition buffer layer, 2 is the buffer layer structure, 3 is the laser gain region and waveguide structure, 4 is the grating structure region, and 5 is the ridge waveguide structure.

[0022] Figure 2 This refers to the surface structure of a laser chip. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] Example 1:

[0025] Please see Figures 1 to 2 This invention provides a technical solution: an on-chip integrated high-power U-band multi-wavelength high-speed laser chip, comprising a P-Si substrate, an epitaxial transition buffer layer, a buffer layer structure, a laser gain region and waveguide structure, a grating structure region, and a ridge waveguide structure.

[0026] The epitaxial transition buffer layer mainly includes: a P-GaP buffer layer and a P-GaAs buffer layer;

[0027] The buffer layer structure mainly includes: a P-InP first buffer layer, a P-InGaAsP / P-InP multilayer superlattice structure, and a P-InP second buffer layer;

[0028] The laser gain region and waveguide structure along the growth direction mainly include: P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, and N-InAlAs electron blocking layer.

[0029] The grating structure region mainly includes: N-InP space layer, N-InGaAsP corrosion inhibitor layer, N-InP spacer layer, N-InGaAsP grating layer, and N-InP capping layer;

[0030] The ridge waveguide structure mainly includes: an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer, and an N-InP capping layer.

[0031] The on-chip integrated high-power U-band multi-wavelength high-speed laser chip also includes the following fabrication methods;

[0032] S1: On a P-Si substrate, a P-GaP buffer layer, a P-GaAs buffer layer, and a P-InP first buffer layer are grown first by MOCVD to effectively reduce lattice mismatch.

[0033] S2: The substrate dislocations are effectively filtered by growing a lattice-matched InGaAsP-InP multilayer superlattice structure, and a second P-InP buffer layer is grown.

[0034] S3: Next, grow the laser gain region and waveguide structure: along the growth direction, sequentially generate the P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, and N-InAlAs electron blocking layer, and then continue to generate the InGaAsP etching blocking layer and beam layer, etc., to complete the substrate growth.

[0035] S4: A uniform grating is prepared in the laser region by holographic exposure and wet etching. Finally, an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer, and an N-InP capping layer are grown to complete the epitaxial growth.

[0036] S5: Next, laser and amplifier waveguides are fabricated by photolithography, etching and corrosion. The laser has multiple waveguides with different tilt angles, corresponding to different output target wavelengths. Lasers of different wavelengths are combined and input to the semiconductor optical amplifier chip.

[0037] S6: Electrical isolation between the laser and the amplifier is achieved by ion implantation; a P-type ohmic contact region is formed by photolithography, etching and corrosion, with the corrosion depth reaching the P-InP second buffer layer;

[0038] S7: Next, a SiO2 passivation layer is deposited, and a hole is opened at the top of the ridge waveguide and the P-type ohmic contact area to form a metal contact area. The Ti / Pt / Au metal is evaporated by electron beam, and the alloy forms P-type and N-type ohmic contacts.

[0039] S8: Finally, the chip fabrication is completed by dissociation, laser light emission, and deposition of high-transmittance and high-reflectance optical films on the backlight end face.

[0040] By employing different tilted waveguides corresponding to different grating periods, multiple different wavelengths can be generated on the same grating. Furthermore, by using a P-type substrate and coplanar electrodes, the series resistance and heat dissipation of the chip are effectively reduced. The multi-wavelength lasers are finally combined into a semiconductor optical amplifier. After optical amplification, the overall optical power can be effectively improved, thereby realizing a single-channel output of multi-wavelength, high-power, high-speed laser. The product can be widely used in data centers.

[0041] Example 2: Based on Example 1, please refer to... Figures 1 to 2 ,

[0042] A method for fabricating an on-chip integrated high-power U-band multi-wavelength high-speed laser chip;

[0043] A 2-inch P-Si substrate was placed in the MOCVD growth chamber, and the substrate surface was cleaned by baking with phosphine at high temperature.

[0044] 100 nm P-GaAs and 100 nm GaAs transition layers were grown to transition the lattice constants of Si and InP;

[0045] A 250nm P-InP first buffer layer and 5 pairs of lattice-matched P-InGaAsP / P-InP (5 / 5nm) superlattice structures were grown to filter substrate dislocations, and a 500nm P-InP second buffer layer was grown.

[0046] Next, a 50 nm P-InGaAlAs lower waveguide layer, a 10 nm strained InGaAlAs multiple quantum well, a 50 nm N-InGaAlAs upper waveguide layer, and a 30 nm N-InAlAs electron blocking layer were grown.

[0047] The substrate was grown by growing a 50nm N-InP spacer layer, a 20nm N-InGaAsP etch stop layer, a 35nm N-InP spacer layer, a 30nm N-InGaAsP grating layer, and a 20nm N-InP capping layer.

[0048] A uniform grating is fabricated in the laser region using photolithography, holographic exposure, and chemical etching. Then, a 1.8-micron N-InP space layer, a 50-nm N-InGaAsP transition layer, a 300-nm N-InGaAs heavily doped ohmic contact layer, and a 20-nm N-InP capping layer are epitaxially grown to complete the epitaxial structure growth. Helium ion implantation is then performed on the epitaxial wafer to form an electrically isolated region between the laser and the amplifier.

[0049] Remove the N-InP capping layer from the epitaxial wafer surface, deposit a 200nm SiO2 dielectric layer via PECVD, and form the desired structure through photolithography and wet etching. Figure 2 The laser, amplifier, and connected waveguide structure shown are illustrated (where...). Figure 2 It contains four high-speed DFB laser chips with different output wavelengths. In the figure, P represents the P-type contact electrode of the chip. The output wavelength of the laser is determined by the waveguide tilt angle. Different tilt angles correspond to different effective grating periods. The four high-speed lasers with different wavelengths are combined and then fed into a semiconductor optical amplifier (SOA). After optical amplification, high-power combined high-speed laser output is achieved. The typical single-mode bottom waveguide width is 1.8 micrometers and the waveguide depth is around 2.2 micrometers.

[0050] A 200nm SiO2 dielectric layer was deposited, and a P-type electrode contact region was formed by photolithography and wet etching, with the etching depth reaching the P-InP second buffer layer.

[0051] Next, a 400nm SiO2 passivation layer was deposited, and the top of the ridge waveguide and the P-type metal contact area were formed on the chip surface by photolithography and etching; Ti / Pt / Au was deposited as the P-type and N-type metals of the chip, and alloyed at 425℃ in a nitrogen atmosphere for 1 min to form ohmic contacts;

[0052] The chip is disassembled into bars. The typical chip cavity length is 1200 micrometers, of which the laser chip cavity length is 180 micrometers, the cavity length of the connecting wavelength region is 220 micrometers, the cavity length of the semiconductor optical amplifier chip is 800 micrometers, the light output waveguide of the semiconductor optical amplifier chip forms a 7° angle with the normal direction of the end face, and the chip width is 800 micrometers.

[0053] Multilayer Si / Al2O3 optical thin films are deposited on the light-emitting end face (SOA end) and the back light end face (laser end) of the chip to form high-transmittance and high-reflection films, respectively, to complete the chip fabrication.

[0054] This invention employs different tilted waveguides corresponding to different grating periods and output wavelengths. Through calculation, multiple target wavelengths can be achieved on a single chip, for example... Figure 2 By reasonably setting the tilt angle of the ridge waveguide, the laser can simultaneously output four wavelengths: 1621nm, 1641nm, 1661nm, and 1681nm. Its performance can achieve 100G long-distance transmission, replacing traditional discrete optical devices.

[0055] Using an epitaxial P-type substrate and coplanar electrodes effectively reduces the device's series resistance and heat dissipation, and further amplifies the high-speed laser beam from multiple beams through SOA.

[0056] The product features low power consumption, on-chip integration, multi-wavelength combined high-speed output, and its performance meets the requirements for long-distance high-speed communication. It can replace traditional high-speed optical devices and is compatible with silicon-based optoelectronic integration.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An on-chip integrated high-power U-band multi-wavelength high-speed laser chip, characterized in that: This includes a P-Si substrate, an epitaxial transition buffer layer, a buffer layer structure, a laser gain region and waveguide structure, a grating structure region, and a ridge waveguide structure. The epitaxial transition buffer layer mainly includes: a P-GaP buffer layer and a P-GaAs buffer layer; The buffer layer structure mainly includes: a P-InP first buffer layer, a P-InGaAsP / P-InP multilayer superlattice structure, and a P-InP second buffer layer; The laser gain region and waveguide structure along the growth direction mainly include: P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, and N-InAlAs electron blocking layer. The grating structure region mainly includes: N-InP space layer, N-InGaAsP corrosion inhibitor layer, N-InP spacer layer, N-InGaAsP grating layer, and N-InP capping layer; The ridge waveguide structure mainly includes: an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer, and an N-InP capping layer; It also includes the following preparation methods; S1: On a P-Si substrate, a P-GaP buffer layer, a P-GaAs buffer layer, and a P-InP first buffer layer are grown by MOCVD to effectively reduce lattice mismatch. S2: Effectively filter substrate dislocations by growing a lattice-matched InGaAsP-InP multilayer superlattice structure, and grow a second P-InP buffer layer; S3: Next, grow the laser gain region and waveguide structure, grating structure region: along the growth direction, sequentially generate the P-InGaAlAs lower waveguide structure, strained InGaAlAs multiple quantum wells, N-InGaAlAs upper waveguide structure, N-InAlAs electron blocking layer, N-InP space layer, N-InGaAsP etch stop layer, N-InP spacer layer, N-InGaAsP grating layer and N-InP capping layer to complete the substrate growth; S4: A uniform grating is prepared in the laser region by holographic exposure and wet etching. Finally, an N-InP space layer, an N-InGaAsP transition layer, an N-InGaAs heavily doped ohmic contact layer and an N-InP capping layer are grown to complete the epitaxial growth. S5: Next, lasers and semiconductor optical amplifiers are fabricated by photolithography, etching and corrosion methods. The lasers have multiple waveguides with different tilt angles, corresponding to different output target wavelengths. Lasers of different wavelengths are combined and input to the semiconductor optical amplifier. S6: Electrical isolation between the laser and the semiconductor optical amplifier is achieved by ion implantation; a P-type ohmic contact region is formed by photolithography, etching and corrosion, with the corrosion depth reaching the P-InP second buffer layer; S7: Next, a SiO2 passivation layer is deposited, and a hole is opened at the top of the ridge waveguide and the P-type ohmic contact area to form a metal contact area. The Ti / Pt / Au metal is evaporated by electron beam, and the alloy forms P-type and N-type ohmic contacts. S8: Finally, the chip fabrication is completed by dissociation, laser light emission, and deposition of high-transmittance and high-reflectance optical films on the backlight end face.

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