A laser-pumped lithium niobate waveguide photonic integrated device and its preparation and application

Abstract

The present invention belongs to the technical field of photon integration and optical waveguide, and specifically relates to a laser-pumped lithium niobate waveguide photon integrated device and its preparation and application. The lithium niobate waveguide in the LNOI optical waveguide laser pumped by the edge-emitting laser in the photon integrated device prepared by the present invention can output spontaneous oscillation laser, and gratings are etched at both ends of the lithium niobate waveguide to form a resonant cavity, which can induce rare earth ions in the optical waveguide to achieve energy level transition and output laser of corresponding wavelength, thereby achieving the advantages of high coupling efficiency, and the preparation process is simple and suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of photon integration and optical waveguide, and more specifically, relates to a laser-pumped lithium niobate waveguide photon integrated device and its preparation and application. Background Art

[0002] Lithium niobate (LN) crystal has a wide transmission window (0.35-5 μm), a high nonlinear coefficient (30 pm / V), a high refractive index (~2.2) and a large electro-optic coefficient (30.8×1012 m / V). It is an important candidate for the substrate material of photonic integrated devices and is known as the "silicon in photonics". However, for a long time, it has been very difficult to prepare photonic structures on lithium niobate substrates. This is mainly because lithium niobate crystals have stable physical and chemical properties and cannot be precisely etched like similar semiconductor lithography technology. In addition, lithium niobate crystals are indirect bandgap materials, and it is difficult to achieve electrically pumped luminescence. Therefore, photoluminescence is generally achieved by doping lithium niobate thin films (LNOI) with rare earth ions. However, traditional rare earth-doped LNOI lasers are all based on micro-disk cavities, which are mainly pumped and signal extracted by tapered fiber coupling. This has the limitations of coupling uncertainty and the inability to integrate other functional devices on the same chip in the later stage. In addition, optical interconnection between optical fiber or optical chip and LNOI-based optical waveguide will also face difficulties such as coupling difficulty, low coupling efficiency, and complex process (Qiao Lingling, Ultra-low Loss Lithium Niobate Photonics [J], Acta Optica Sinica, 2021, 8, 169-194). Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of low coupling efficiency of existing rare earth doped LNOI lasers and provide a laser pumped lithium niobate waveguide photonic integrated device with high coupling efficiency.

[0004] The purpose of the present invention is to provide a method for preparing a laser-pumped lithium niobate waveguide photonic integrated device.

[0005] Another object of the present invention is to provide a laser pumped lithium niobate waveguide photonic integrated device for use as a chip.

[0006] A laser-pumped lithium niobate waveguide photonic integrated device, characterized in that it consists of a p-type substrate, an edge-emitting laser, an LNOI optical waveguide laser, a p-side electrode and an n-side electrode, wherein the p-side electrode, the bonded edge-emitting laser and the LNOI optical waveguide laser are sputtered in sequence from left to right above the p-type substrate, and the n-side electrode is sputtered on the surface of the edge-emitting laser;

[0007] The LNOI optical waveguide laser comprises a photoresist, a lithium niobate substrate and a SiO2 layer from top to bottom, an ion implantation damage layer is implanted in the lithium niobate substrate, a strip waveguide structure pattern is etched on the surface of the lithium niobate substrate through the photoresist, the strip waveguide structure pattern contains a lithium niobate waveguide, a backward grating and a forward grating are etched in the lithium niobate substrate through both ends of the strip waveguide structure pattern, rare earth ions are implanted in the lithium niobate substrate so that the rare earth ions are dispersed in the lithium niobate substrate, and an end face is provided on the left side;

[0008] The edge emitting laser is provided with a light outlet on the right side, which faces the end face of the LNOI optical waveguide laser, so that the photons emitted by the edge emitting laser pumping rare earth ion energy level transition are emitted in the front and rear gratings.

[0009] Preferably, the strip waveguide structure pattern is, from left to right, a lithium niobate waveguide input end, a second tapered transition waveguide, a lithium niobate waveguide, a first tapered transition waveguide, and a lithium niobate waveguide output end; wherein the backward grating is etched on the left side of the first tapered transition waveguide, and the forward grating is etched on the right side of the second tapered transition waveguide.

[0010] More preferably, the length L2 of the lithium niobate waveguide and the lithium niobate waveguide input end is ≥20μm, the width w is 200nm-1000nm, the length L1 of the first tapered transition waveguide and the second tapered transition waveguide is ≥20μm, and the width M is 0.5μm-100μm.

[0011] Preferably, the edge emitting laser sputters the n-side electrode from top to bottom, depositing an n-type substrate, an n-type buffer layer, an n-type confinement layer, an n-type waveguide layer, a quantum well active region, a p-type waveguide layer, a p-type confinement layer and a p-type contact layer.

[0012] Preferably, the rare earth ions are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium or yttrium ions.

[0013] Preferably, the substrate in the p-type substrate and the n-type substrate is a gallium arsenide substrate, a silicon substrate, a sapphire substrate, a diamond substrate, a gallium nitride substrate, a silicon carbide substrate or an indium phosphide substrate.

[0014] Preferably, the grating is a Bragg grating.

[0015] More preferably, the thickness of the SiO2 layer is 0.5-10 μm.

[0016] Preferably, the thickness of the lithium niobate substrate is 0.1-10 μm.

[0017] The present invention further protects a method for preparing the above integrated device, comprising the following steps:

[0018] S1. Depositing a SiO2 layer on a lithium niobate substrate by plasma chemical vapor deposition or magnetron sputtering, and injecting helium ions into the lithium niobate substrate in the SiO2 layer by ion implantation to form an ion implantation damage layer;

[0019] S2. polishing the surface of the SiO2 layer by a chemical mechanical polishing process to reduce the surface roughness of the SiO2 to less than 1 nm, and then bonding it to a p-type gallium arsenide substrate to obtain a wafer bonding pair, wherein the bonding process is as follows: firstly bombarding and activating the p-type substrate and the surface of the SiO2 layer by plasma, and then bonding the p-type substrate to the wafer bonding pair bonded to the SiO2 layer;

[0020] S3. Annealing the wafer bonding pair to peel off the lithium niobate substrate above the ion implantation damage layer, and after peeling off, polishing the lithium niobate substrate, and after polishing, injecting rare earth ions into the lithium niobate substrate;

[0021] S4. Coating a layer of photoresist on the polished lithium niobate substrate, then exposing the surface of the photoresist, transferring the strip waveguide structure pattern to the photoresist by photolithography, and then etching the strip waveguide structure pattern onto the lithium niobate substrate by electron beam lithography combined with an inductively coupled plasma etcher;

[0022] S5. Using a femtosecond laser to penetrate a strip waveguide structure pattern, a backward grating and a forward grating are etched in a lithium niobate substrate to obtain an LNOI optical waveguide laser;

[0023] S6. epitaxially grow an n-type buffer layer, an n-type confinement layer, an n-type waveguide layer, a quantum well active region, a p-type waveguide layer, a p-type confinement layer and a p-type contact layer on an n-type substrate in sequence by metal organic chemical vapor deposition. After the epitaxial growth is completed, the p-type contact layer is polished to reduce the surface roughness of the p-type contact layer to less than 1 nm. A high reflection film and an anti-reflection film are respectively evaporated on the reflection end face and the emission end face to obtain an edge emitting laser;

[0024] S7. Bond an edge emitting laser to a p-type substrate, with the light outlet of the edge emitting laser aligned with the end face of the LNOI optical waveguide laser; sputter a p-side electrode on the p-type substrate, and sputter an n-side electrode on the n-type substrate.

[0025] Preferably, in step S1, the thickness of the SiO2 layer is 0.5-10 μm.

[0026] Preferably, in step S1, the implanted dose is 1×10 15 cm -2 ~1×10 19 cm -2 .

[0027] Preferably, in step S1, the injected energy is 100-700 keV

[0028] Preferably, in step S1, the deposition gas pressure is 1200-1600 mtorr, the power is 4000-6000 W, and the deposition temperature is 300-500°C.

[0029] Preferably, in step S2, the plasma is Ar plasma, O plasma or N plasma.

[0030] Preferably, in step S2, the gas pressure of the plasma bombardment is 0.5×10 -5 ~1×10 -5 Pa.

[0031] Preferably, in step S2, the bonding force of the bonding is 8-12 kN.

[0032] Preferably, in step S2, the bonding time is 0.8 to 0.5 min.

[0033] Preferably, in step S3, the rare earth ions are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium or yttrium ions.

[0034] Preferably, in step S3, the annealing time is 1 to 10 hours.

[0035] Preferably, in step S3, the annealing temperature is 100-600°C.

[0036] Preferably, in step S3, the heating rate of the annealing is 2-10°C / min.

[0037] Preferably, in step S3, the annealing is performed under an inert gas.

[0038] Preferably, in step S3, the inert gas is nitrogen.

[0039] More preferably, the flow rate of the inert gas is 0.1 to 10 L / h.

[0040] Preferably, in step S3, the method of injecting rare earth ions is ion implantation technology or thermal diffusion technology.

[0041] Preferably, in step S3, the implantation energy is 10-1000 keV.

[0042] More preferably, the implantation dose of the rare earth ions is 1×10 11 cm -2 ~1×10 18 cm -2 .

[0043] Preferably, in step S4, the thickness of the chromium layer is greater than 200 nm.

[0044] Preferably, in step S4, the photolithography method is electron beam lithography, ultraviolet exposure technology or photolithography development technology.

[0045] Preferably, in step S4, the photoresist is a positive photoresist.

[0046] Preferably, in step S4, during the photolithography, a mask is placed on the lithium niobate substrate, and after the photolithography is completed, development and hardening are performed to finally form a ridge waveguide.

[0047] Preferably, in step S5, the logarithm and spacing of the gratings in the backward grating and the forward grating are determined based on optical coupling mode theory, the backward grating serves as the laser output end, and the forward grating serves as a total reflection mirror, and the reflectivity can be adjusted by controlling the length of the grating.

[0048] Preferably, in step S6, the n-type buffer layer is an n-type gallium arsenide buffer layer or an n-type gallium nitride buffer layer.

[0049] More preferably, the thickness of the n-type buffer layer is 1-3 μm, and the doping concentration is 0.5×10 18 ~1×10 18 / cm 2 .

[0050] Preferably, in step S6, the n-type confinement layer is an n-type Al x Ga 1-x As confinement layer or n-type Al x Ga 1-x N restriction layers, the value range of x is 0<x<1.

[0051] More preferably, the thickness of the n-type confinement layer is 500-650 nm, and the doping concentration is 4×10 17 ~6×10 17 / cm 2 .

[0052] Preferably, in step S6, the n-type waveguide layer is an n-type Al x Ga 1-x As waveguide layer or n-type In x Ga 1-x As waveguide layer, the value range of x is 0<x<1.

[0053] More preferably, the thickness of the n-type waveguide layer is 200-400 nm, and the doping concentration is 4×10 16 ~6×10 16 / cm2 .

[0054] Preferably, in step S6, the quantum well active region is In x Ga 1-x N.

[0055] More preferably, the thickness of the quantum well active region is 5-10 nm.

[0056] Preferably, in step S6, the p-type waveguide layer is p-type Al x Ga 1-x As waveguide layer or p-type In x Ga 1-x As waveguide layer, the value range of x is 0<x<1.

[0057] More preferably, the thickness of the p-type waveguide layer is 200-400 nm, and the doping concentration is 4×10 16 ~6×10 16 / cm 2 .

[0058] Preferably, in step S6, the p-type confinement layer is a p-type Al x Ga 1-x As confinement layer or p-type Al x Ga 1-x As limiting layer, the value range of x is 0<x<1.

[0059] More preferably, the thickness of the p-type confinement layer is 500-700 nm, and the doping concentration is 4×10 17 ~6×10 17 / cm 2 .

[0060] Preferably, in step S6, the p-type contact layer is a p-type GaAs contact layer or a p-type InGaN contact layer.

[0061] More preferably, the thickness of the p-type contact layer is 40-60 nm, and the doping concentration is 1×10 18 ~6×10 18 / cm 2 .

[0062] Preferably, in step S6, the material of the high-reflection film is Ta2O5, Si or HfO2, and the material of the anti-reflection film is CeF3, MgF2, Al2O3 or ZrO2.

[0063] The present invention further protects the application of the above-mentioned photonic integrated device as a chip.

[0064] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "width", "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0065] The present invention has the following beneficial effects:

[0066] The lithium niobate waveguide in the edge-emitting laser-pumped LNOI optical waveguide laser in the photonic integrated device prepared by the present invention can spontaneously oscillate laser output, and gratings are etched at both ends of the lithium niobate waveguide to form a resonant cavity, which can induce rare earth ions in the optical waveguide to achieve energy level transition and output laser of corresponding wavelength, thereby achieving the advantage of high coupling efficiency, and the preparation process is simple and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic structural diagram of a gallium arsenide laser pumped lithium niobate waveguide photonic integrated device according to Example 1 of the present invention.

[0068] Figure 2 It is an enlarged front view of the GaAs basal edge emitting laser 22 in the GaAs laser pumped lithium niobate waveguide photonic integrated device according to Example 1 of the present invention.

[0069] Figure 3 It is an enlarged right view of the LNOI optical waveguide laser 21 in the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device according to Example 1 of the present invention.

[0070] Figure 4 It is an enlarged front view of the LNOI optical waveguide laser 21 in the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device according to Example 1 of the present invention.

[0071] Figure 5 This is an enlarged top view of the LNOI optical waveguide laser 21 in the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device according to Example 1 of the present invention.

[0072] Among them, 1-lithium niobate substrate, 2-SiO2 layer, 3-ion implantation damage layer, 4-p-type gallium arsenide substrate, 4'-n-type gallium arsenide substrate, 5-lithium niobate waveguide output end, 6-first tapered transition waveguide, 7-lithium niobate waveguide, 8-second tapered transition waveguide, 9-lithium niobate waveguide input end, 10-backward grating, 11-forward grating, 12-n-type gallium arsenide buffer layer, 13-n-type Al 0.20 Ga 0.80 As confinement layer, 14-n type Al 0.50 Ga 0.50As waveguide layer, 15-quantum well active region, 16-p-type Al 0.8 Ga 0.2 As waveguide layer, 17-p type Al 0.8 Ga 0.2 As confinement layer, 18-p-type GaAs contact layer, 19-n-surface electrode, 20-p-surface electrode, 21-LNOI optical waveguide, 22-GaAs-based edge emitting laser, 23-light outlet of GaAs-based edge emitting laser 22, 24-end face of LNOI optical waveguide laser 21, 25-waveguide structure pattern.

[0073] Figure 6 This is a graph showing the conversion efficiency of the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device obtained in Example 1.

[0074] Figure 7 This is a graph showing the conversion efficiency of the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device obtained in Example 2.

[0075] Figure 8 This is a graph showing the conversion efficiency of the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device obtained in Example 3.

[0076] Fig. 9 This is a graph showing the conversion efficiency of the gallium arsenide laser pumped lithium niobate waveguide photonic integrated device obtained in Example 4. DETAILED DESCRIPTION

[0077] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0078] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0079] The optical coupled mode theory is as follows:

[0080] The etching of gratings in lithium niobate waveguides is mainly based on the principle of fiber Bragg gratings. The periodic perturbation of the effective refractive index in the fiber Bragg grating allows the core mode to couple to the forward or backward propagation mode, depending on the grating period. It can be understood by ray optics, and the grating is considered to be a typical diffraction grating with a period of Λ. A light wave incident at an angle of θ1 will diffract out of the grating at an angle of θ2, and the grating equation is described as:

[0081] nsinθ2=nsinθ1+mλ / Λ

[0082] Where m is the grating diffraction order. When the incident and diffracted light correspond to the fiber boundary mode, the propagation constant β = 2πn effsinθ / λ gives the phase matching condition for mode coupling:

[0083] β2=β1+2π / Λ

[0084] This equation allows predicting the period of coupling of two modes with transmission constants β1 and β2 at wavelength λ.

[0085] For Bragg grating: coupling occurs between two forward and backward transmission modes, that is, the incident light and the diffracted light are opposite (β2 = -β1), and the resonant wavelength is expressed as:

[0086] mλ=(n eff1 +n eff2 )Λ

[0087] In the Bragg grating, the core mode coupling between forward and reverse propagation is dominant, i.e. Its Bragg resonance condition:

[0088]

[0089] Example 1 Preparation of GaAs laser pumped lithium niobate waveguide photonic integrated device

[0090] S1: providing a lithium niobate substrate 1, and depositing a SiO2 layer 2 with a thickness of 2 μm on the lithium niobate substrate 1 by a plasma chemical vapor deposition (PECVD) process with a gas pressure of 1500 mtorr, a power of 5000 W, and a deposition temperature of 400°C;

[0091] S2: After the SiO2 layer 2 is deposited, helium ions are injected into the lithium niobate substrate 1 through the SiO2 layer 2 using an ion implantation process. The injection energy is 300 keV and the injection dose is 3×10 16 cm -2 , forming an injection damage layer 3, after the injection is completed, the surface of the SiO2 layer 2 is polished by a chemical mechanical polishing process (CMP) process, so that the surface roughness of the SiO2 layer 2 is reduced to less than 1nm;

[0092] S3: Provide a p-type GaAs substrate 4, and bond the polished SiO2 layer 2 in step S2 to the p-type GaAs substrate 4. During the bonding process, the pressure in the chamber is reduced to 1×10 -5 Pa, using Ar plasma to bombard and activate the surface of the p-type gallium arsenide substrate 4 and the SiO2 layer 2. After the activation is completed, they are moved into the bonding chamber, and the p-type gallium arsenide substrate 4 and the SiO2 layer 2 are bonded together to obtain a wafer bonding pair. The bonding force applied is 10kN, and the bonding time is 1min;

[0093] S4: After bonding is completed, the wafer bonding pair is moved to an annealing furnace for annealing. The temperature in the annealing furnace is slowly increased at a temperature rise rate of 2°C / min to 300°C for 5 hours. During the annealing process, nitrogen is introduced into the furnace at a flow rate of 5L / h. When the lithium niobate substrate 1 above the ion-implanted damaged layer 3 is peeled off, heating can be stopped, and the sample is taken out after cooling to room temperature;

[0094] S5: Polishing the lithium niobate substrate 1 film left after peeling. After polishing, rare earth ions are injected into the lithium niobate substrate 1 film. The injected ions are thulium ions (Tm 3+ ), the implantation energy is 200 keV, and the ion implantation dose is 5×10 15 cm -2 After the implantation is completed, the ion implantation chamber is taken out for future use;

[0095] S6: The optical waveguide is prepared on the lithium niobate substrate 1 thin film. First, a layer of photoresist is coated on the surface of the exposed p-type gallium arsenide substrate 4 for protection. Then, the surface of the photoresist is exposed. The strip waveguide structure pattern 25 is transferred to the photoresist by photolithography using electron beam lithography technology. During photolithography, a mask is placed on the lithium niobate substrate. After the photolithography is completed, it is developed and hardened to finally form a ridge waveguide ( Figure 3 ), the photoresist may be positive photoresist AZ5214, and then the strip waveguide structure pattern 25 is etched onto the lithium niobate substrate 1 film by electron beam lithography (EBL) technology combined with an inductively coupled plasma etcher (ICP-RIE). In order to achieve efficient coupling with the gallium arsenide basal edge emitting laser 22, the waveguide structure is arranged to be, from right to left, a lithium niobate waveguide output end 5, a first tapered transition waveguide 6, a lithium niobate waveguide 7, a second tapered transition waveguide 8, and a lithium niobate waveguide input end 9. The length of the first tapered transition waveguide 6 and the second tapered transition waveguide 8 is 20 μm, and the width is 2 μm, which can improve the coupling efficiency of the light source. In addition, the length of the lithium niobate waveguide 7 is 25 μm, and the width is 400 nm.

[0096] S7: Using a femtosecond laser to perform grating etching into the lithium niobate substrate 1 through the strip waveguide structure pattern 25 to obtain the LNOI optical waveguide laser 21 ( Figure 3 to Figure 5 ), the number of logarithms and the spacing of the gratings are determined according to the optical coupling mode theory, the forward grating 11 with a logarithm of 200 is etched to increase the reflectivity of the forward grating 11, and the backward grating 10 with a logarithm of 15 is etched to reduce the reflectivity of the backward grating 10, thereby forming the front and rear cavity surfaces of the resonant cavity, the backward grating 10 is used as the laser output end, and the forward grating 11 is used as a total reflection mirror, and the reflectivity can be adjusted by controlling the length of the grating;

[0097] S8: Provide an n-type GaAs substrate 4', and sequentially epitaxially grow a 2 μm thick n-type GaAs buffer layer 12 (doping concentration is 1×10 18 / cm 2 ), 600nm thick n-type Al 0.20 Ga 0.80 As confinement layer 13 (doping concentration is 5×10 17 / cm 2 ), 300nm thick n-type Al 0.50 Ga 0.50 As waveguide layer 14 (doping concentration is 5×10 16 / cm 2 ), the 7nm thick quantum well active region 15 is In 0.19 Ga 0.81 As, 300nm thick p-type Al 0.8 Ga 0.2 As waveguide layer 16 (doping concentration is 5×10 16 / cm 2 ), 600nm thick p-type Al 0.8 Ga 0.2 As confinement layer 17 (doping concentration is 5×10 17 / cm 2 ) and a 50nm thick p-type GaAs contact layer 18 (doping concentration is 1×10 18 / cm 2 After the epitaxial growth is completed, the top p-type GaAs contact layer 18 is CMP polished to reduce the surface roughness of the p-type GaAs contact layer 18 to less than 1 nm, and a high-reflection film and an anti-reflection film are evaporated on the reflection end face and the emission end face to obtain a GaAs-based edge-emitting laser 22 ( Figure 2 ), the material of the high reflection film is Ta2O5, and the material of the anti-reflection film can be CeF3;

[0098] S9: After the p-type GaAs contact layer 18 is polished, the LNOI optical waveguide laser 21 is bonded to the p-type GaAs substrate 4, and the light outlet 23 of the GaAs basal edge emitting laser 22 is aligned with the end face 24 of the LNOI optical waveguide laser 21;

[0099] S10: sputter a p-side electrode 20 on the p-type GaAs substrate 4 and on the left side of the GaAs base edge emitting laser 22, and sputter an n-side electrode 19 on the surface of the n-type GaAs substrate 4' on the top of the GaAs base edge emitting laser 22 to obtain a GaAs laser pumped lithium niobate waveguide photonic integrated device ( Figure 1 ).

[0100] Example 2 Preparation of GaAs laser pumped lithium niobate waveguide photonic integrated device

[0101] S1: providing a lithium niobate substrate 1, and depositing a SiO2 layer 2 with a thickness of 2 μm on the lithium niobate substrate 1 by a plasma chemical vapor deposition (PECVD) process with a gas pressure of 1500 mtorr, a power of 5000 W, and a deposition temperature of 400°C;

[0102] S2: After the SiO2 layer 2 is deposited, helium ions are injected into the lithium niobate substrate 1 through the SiO2 layer 2 using an ion implantation process. The injection energy is 300 keV and the injection dose is 3×10 16 cm -2 , forming an injection damage layer 3, after the injection is completed, the surface of the SiO2 layer 2 is polished by a chemical mechanical polishing process (CMP) process, so that the surface roughness of the SiO2 layer 2 is reduced to less than 1nm;

[0103] S3: Provide an n-type GaAs substrate 4', and sequentially epitaxially grow a 1.5 μm thick n-type GaAs buffer layer 12 (doping concentration is 1×10 18 / cm 2 ), 700nm thick n-type Al 0.20 Ga 0.80 As confinement layer 13 (doping concentration is 5×10 17 / cm 2 ), 300nm thick n-type Al 0.50 Ga 0.50 As waveguide layer 14 (doping concentration is 6×10 16 / cm 2 ), the 7nm thick quantum well active region 15 is In 0.19 Ga 0.81 As, 300nm thick p-type Al 0.8 Ga 0.2 As waveguide layer 16 (doping concentration is 6×10 16 / cm 2 ), 600nm thick p-type Al 0.8 Ga 0.2 As confinement layer 17 (doping concentration is 5×10 17 / cm 2 ) and a 50nm thick p-type GaAs contact layer 18 (doping concentration is 1×10 18 / cm 2 )GaAs-based edge emitting laser 22.

[0104] S4: After the epitaxial growth, a positive photoresist is applied to a part of the n-type GaAs substrate 4', and the uncoated area is etched to a depth of 5 μm. The etched area is polished by CMP process to reduce the surface roughness to 0.5 nm. The SiO2 layer 2 polished in step S2 is bonded to the etched area. During the bonding process, the pressure in the chamber is reduced to 1×10 -5 Pa, using Ar plasma to bombard and activate the gallium arsenide and SiO2 surfaces, after activation, move them into a bonding chamber, bond the n-type gallium arsenide substrate 4' and the SiO2 layer 2 together to obtain a wafer bonding pair, the applied bonding force is 10kN, the bonding time is 1min, and a high reflection film and an anti-reflection film are evaporated on the reflection end face and the emission end face to obtain a LNOI optical waveguide laser 21, the material of the high reflection film is Ta2O5, and the material of the anti-reflection film can be CeF3;

[0105] S5: After bonding is completed, the wafer bonding pair is moved to an annealing furnace for annealing. The temperature in the annealing furnace is slowly increased at a temperature rise rate of 2°C / min to 300°C for 5 hours. During the annealing process, nitrogen is introduced into the furnace at a flow rate of 5L / h. When the top lithium niobate substrate 1 is peeled off, heating can be stopped, and the sample is taken out after cooling to room temperature;

[0106] S6: Polishing the lithium niobate substrate 1 film left after peeling. After polishing, rare earth ions are injected into the lithium niobate substrate 1 film. The injected ions are thulium ions (Tm 3+ ), the implantation energy is 200 keV, and the ion implantation dose is 5×10 15 cm -2 After the implantation is completed, the ion implantation chamber is taken out for future use;

[0107] S7: The top lithium niobate substrate 1 thin film is used to prepare an optical waveguide. First, a layer of photoresist can be coated on the surface of the exposed n-type gallium arsenide substrate 4' for protection. Then, the surface of the photoresist is exposed. The strip waveguide structure pattern 25 is transferred to the photoresist by photolithography using electron beam lithography technology. During photolithography, a mask is placed on the lithium niobate substrate. After the photolithography is completed, it is developed and hardened to finally form a ridge waveguide. The photoresist can be positive photoresist AZ5214. Then, the electron beam lithography (EBL) technology is combined with an inductively coupled plasma etcher (I CP-RIE) etches a strip waveguide structure pattern 25 onto a lithium niobate substrate 1 film. In order to achieve efficient coupling with a gallium arsenide basal edge emitting laser 22, the waveguide structure is arranged to be, from right to left, a lithium niobate waveguide output end 5, a first tapered transition waveguide 6, a lithium niobate waveguide 7, a second tapered transition waveguide 8, and a lithium niobate waveguide input end 9. The length of the first tapered transition waveguide 6 and the second tapered transition waveguide 8 is 50 μm, and the width is 2 μm, which can improve the coupling efficiency of the light source. In addition, the length of the lithium niobate waveguide 7 is 25 μm, and the width is 500 nm.

[0108] S8: using a femtosecond laser to perform grating etching into the lithium niobate substrate 1 through the strip waveguide structure pattern 25 to obtain an LNOI optical waveguide laser 21. The number of gratings and the spacing are determined according to the optical coupling mode theory. The forward grating 11 with a number of 250 pairs is etched to increase the reflectivity of the forward grating 11. The backward grating 10 with a number of 10 pairs is etched to reduce the reflectivity of the backward grating 10, thereby forming the front and rear cavity surfaces of the resonant cavity. The backward grating 10 serves as the laser output end, and the forward grating 11 serves as a total reflection mirror. The reflectivity can be adjusted by controlling the length of the grating.

[0109] S9: polishing the p-type GaAs contact layer 18 in step S4. After polishing, bonding the LNOI optical waveguide laser 21 to the p-type GaAs substrate 4, aligning the light outlet 23 of the GaAs basal edge emitting laser 22 with the end face 24 of the LNOI optical waveguide laser 21;

[0110] S10: sputter a p-side electrode 20 on the p-type GaAs substrate 4 and on the left side of the GaAs-based edge emitting laser 22, and sputter an n-side electrode 19 on the uppermost surface of the n-type GaAs substrate 4' of the GaAs-based edge emitting laser 22 to obtain a GaAs laser pumped lithium niobate waveguide photonic integrated device.

[0111] Example 3 Preparation of GaAs laser pumped lithium niobate waveguide photonic integrated device

[0112] S1: providing a lithium niobate substrate 1, depositing a SiO2 layer 2 on the lithium niobate substrate 1, with a thickness of 2 μm, using a plasma chemical vapor deposition (PECVD) process, a gas pressure of 1500 mtorr, a power of 5000 W, and a deposition temperature of 400°C;

[0113] S2: After the SiO2 layer 2 is deposited, helium ions are injected into the lithium niobate substrate 1 through the SiO2 layer 2 using an ion implantation process. The injection energy is 300 keV and the injection dose is 3×10 16 cm -2 , forming an injection damage layer 3, after the injection is completed, the surface of the SiO2 layer 2 is polished by a chemical mechanical polishing process (CMP) process, so that the surface roughness of the SiO2 layer 2 is reduced to less than 1nm;

[0114] S3: Provide a p-type GaAs substrate 4, and bond the polished SiO2 layer 2 in step S2 to the p-type GaAs substrate 4. During the bonding process, the pressure in the chamber is reduced to 1×10 -5 Pa, using Ar plasma to bombard and activate the surface of the p-type gallium arsenide substrate 4 and the SiO2 layer 2. After the activation is completed, they are moved into the bonding chamber, and the p-type gallium arsenide substrate 4 and the SiO2 layer 2 are bonded together to obtain a wafer bonding pair. The bonding force applied is 10kN, and the bonding time is 1min;

[0115] S4: After bonding is completed, the wafer bonding pair is moved to an annealing furnace for annealing. The temperature in the annealing furnace is slowly increased at a temperature rise rate of 2°C / min to 300°C for 5 hours. During the annealing process, nitrogen is introduced into the furnace at a flow rate of 5L / h. When the lithium niobate substrate 1 above the ion-implanted damaged layer 3 is peeled off, heating can be stopped, and the sample is taken out after cooling to room temperature;

[0116] S5: Polishing the lithium niobate substrate 1 film left after peeling. After polishing, rare earth ions are injected into the lithium niobate substrate 1 film. The injected ions are erbium ions (Er 3+ ), the implantation energy is 220keV, and the ion implantation dose is 5×10 16 cm -2 After the implantation is completed, the ion implantation chamber is taken out for future use;

[0117] S6: The top lithium niobate substrate 1 thin film is used to prepare an optical waveguide. First, a layer of photoresist is applied on the surface of the exposed p-type gallium arsenide substrate 4 for protection. Then, the surface of the photoresist is exposed. The strip waveguide structure pattern 25 is transferred to the photoresist by photolithography using electron beam lithography technology. During photolithography, a mask is placed on the lithium niobate substrate. After the photolithography is completed, the film is developed and hardened to finally form a ridge waveguide. The photoresist can use positive photoresist AZ5214. Then, the electron beam lithography (EBL) technology is combined with an inductively coupled plasma etcher (ICP etcher). P-RIE) etches a strip waveguide structure pattern 25 onto the lithium niobate substrate 1 film. In order to achieve efficient coupling with the gallium arsenide base edge emitting laser 22, the waveguide structure is set to be, from right to left, a lithium niobate waveguide output end 5, a first tapered transition waveguide 6, a lithium niobate waveguide 7, a second tapered transition waveguide 8, and a lithium niobate waveguide input end 9. The length of the first tapered transition waveguide 6 and the second tapered transition waveguide 8 is 20 μm, and the width is 2 μm, which can improve the coupling efficiency of the light source. In addition, the length of the lithium niobate waveguide 7 is 25 μm, and the width is 400 nm.

[0118] S7: using a femtosecond laser to perform grating etching into the lithium niobate substrate 1 through the strip waveguide structure pattern 25 to obtain an LNOI optical waveguide laser 21. The number of gratings and the spacing are determined according to the optical coupling mode theory. The forward grating 11 with a number of 300 is etched to increase the reflectivity of the forward grating 11. The backward grating 10 with a number of 15 pairs is etched to reduce the reflectivity of the backward grating 10, thereby forming the front and rear cavity surfaces of the resonant cavity. The backward grating 10 serves as the laser output end, and the forward grating 11 serves as a total reflection mirror. The reflectivity can be adjusted by controlling the length of the grating.

[0119] S8: Provide an n-type GaAs substrate 4', and sequentially epitaxially grow a 2 μm thick n-type GaAs buffer layer 12 (doping concentration is 1×10 18 / cm 2 ), 600nm thick n-type Al 0.20 Ga 0.80 As confinement layer 13 (doping concentration is 5×10 17 / cm 2 ), 300nm thick n-type Al 0.50 Ga 0.50 As waveguide layer 14 (doping concentration is 5×10 16 / cm 2 ), the 7nm thick quantum well active region 15 is In 0.19 Ga 0.81 As, 300nm thick p-type Al 0.7 Ga 0.3As waveguide layer 16 (doping concentration is 5×10 16 / cm 2 ), 600nm thick p-type Al 0.7 Ga 0.3 As confinement layer 17 (doping concentration is 5×10 17 / cm 2 ) and a 50nm thick p-type GaAs contact layer 18 (doping concentration is 1×10 18 / cm 2 After the epitaxial growth is completed, the top p-type GaAs contact layer 18 is CMP polished to reduce the surface roughness of the p-type GaAs contact layer 18 to less than 1 nm, and a high-reflection film and an anti-reflection film are respectively evaporated on the reflection end face and the emission end face to obtain a GaAs-based edge emitting laser 22, the material of the high-reflection film is Ta2O5, and the material of the anti-reflection film can be CeF3;

[0120] S9: After the p-type GaAs contact layer 18 is polished, the LNOI optical waveguide laser 21 is bonded to the p-type GaAs substrate 4, and the light outlet 23 of the GaAs basal edge emitting laser 22 is aligned with the end face 24 of the LNOI optical waveguide laser 21;

[0121] S10: sputter a p-side electrode 20 on the p-type GaAs substrate 4 and on the left side of the GaAs-based edge emitting laser 22, and sputter an n-side electrode 19 on the uppermost surface of the n-type GaAs substrate 4' of the GaAs-based edge emitting laser 22 to obtain a GaAs laser pumped lithium niobate waveguide photonic integrated device.

[0122] Example 4 Preparation of GaN laser pumped lithium niobate waveguide photonic integrated device

[0123] S1: providing a lithium niobate substrate 1, depositing a SiO2 layer 2 on the lithium niobate substrate 1, with a thickness of 2 μm, using a plasma chemical vapor deposition (PECVD) process, a gas pressure of 1500 mtorr, a power of 5000 W, and a deposition temperature of 400°C;

[0124] S2: After the SiO2 layer 2 is deposited, helium ions are injected into the lithium niobate substrate 1 through the SiO2 layer 2 using an ion implantation process. The injection energy is 300 keV and the injection dose is 3×10 16 cm -2 , forming an injection damage layer 3, after the injection is completed, the surface of the SiO2 layer 2 is polished by a chemical mechanical polishing process (CMP) process, so that the surface roughness of the SiO2 layer 2 is reduced to less than 1nm;

[0125] Step 3: Provide a p-type GaAs substrate 4, and bond the polished SiO2 layer 2 in step S2 to the p-type GaAs substrate 4. During the bonding process, the pressure in the chamber is reduced to 1×10 -5 Pa, using Ar plasma to bombard and activate the surface of the p-type gallium arsenide substrate 4 and the SiO2 layer 2. After the activation is completed, they are moved into the bonding chamber, and the p-type gallium arsenide substrate 4 and the SiO2 layer 2 are bonded together to obtain a wafer bonding pair. The bonding force applied is 10kN, and the bonding time is 1min;

[0126] S4: After bonding is completed, the wafer bonding pair is moved to an annealing furnace for annealing. The temperature in the annealing furnace is slowly increased at a temperature rise rate of 2°C / min to 300°C for 5 hours. During the annealing process, nitrogen is introduced into the furnace at a flow rate of 5L / h. When the lithium niobate substrate 1 above the ion-implanted damaged layer 3 is peeled off, heating can be stopped, and the sample is taken out after cooling to room temperature;

[0127] S5: Polishing the lithium niobate substrate 1 film left after peeling. After polishing, rare earth ions are injected into the lithium niobate substrate 1 film. The injected ions are erbium ions (Er 3+ ), the implantation energy is 220keV, and the ion implantation dose is 5×10 16 cm -2 After the implantation is completed, the ion implantation chamber is taken out for future use;

[0128] S6: preparing an optical waveguide on the lithium niobate substrate 1 thin film. First, a layer of photoresist can be coated on the surface of the exposed p-type gallium arsenide substrate 4 for protection. Then, the surface of the photoresist is exposed. The strip waveguide structure pattern 25 is transferred to the photoresist by photolithography using electron beam lithography technology. During photolithography, a mask is placed on the lithium niobate substrate. After the photolithography is completed, it is developed and hardened to finally form a ridge waveguide. The photoresist can be positive photoresist AZ5214. Then, electron beam lithography (EBL) technology combined with an inductively coupled plasma etcher (ICP) is used to perform optical waveguide preparation. -RIE) etches a strip waveguide structure pattern 25 onto the lithium niobate substrate 1 film. In order to achieve efficient coupling with the gallium arsenide base edge emitting laser 22, the waveguide structure is set to be, from right to left, a lithium niobate waveguide output end 5, a first tapered transition waveguide 6, a lithium niobate waveguide 7, a second tapered transition waveguide 8, and a lithium niobate waveguide input end 9. The length of the first tapered transition waveguide 6 and the second tapered transition waveguide 8 is 20 μm, and the width is 2 μm, which can improve the coupling efficiency of the light source. In addition, the length of the lithium niobate waveguide 7 is 25 μm, and the width is 400 nm;

[0129] S7: using a femtosecond laser to perform grating etching into the lithium niobate substrate 1 through the strip waveguide structure pattern 25 to obtain an LNOI optical waveguide laser 21. The number of gratings and the spacing are determined according to the optical coupling mode theory. The forward grating 11 with a number of 300 is etched to increase the reflectivity of the forward grating 11. The backward grating 10 with a number of 15 pairs is etched to reduce the reflectivity of the backward grating 10, thereby forming the front and rear cavity surfaces of the resonant cavity. The backward grating 10 serves as the laser output end, and the forward grating 11 serves as a total reflection mirror. The reflectivity can be adjusted by controlling the length of the grating.

[0130] S8: Provide an n-type gallium nitride substrate 4', and sequentially epitaxially grow a 2 μm thick n-type gallium nitride buffer layer 12 (doping concentration is 1×10 18 / cm 2 ), 600nm thick n-type Al 0.20 Ga 0.80 N confinement layer 13 (doping concentration is 5×10 17 / cm 2 ), 300nm thick n-type In 0.50 Ga 0.50 As waveguide layer 14 (doping concentration is 5×10 16 / cm 2 ), the 7nm thick quantum well active region 15 is In 0.19 Ga 0.81 As, 300nm thick p-type In 0.02 Ga 0.98 As waveguide layer 16 (doping concentration is 5×10 16 / cm 2 ), 600nm thick p-type Al 0.07 Ga 0.93 As confinement layer 17 (doping concentration is 5×10 17 / cm 2 ) and a 50 nm thick p-type InGaN contact layer 18 (doping concentration is 1×10 18 / cm 2 After the epitaxial growth is completed, the top p-type InGaN contact layer 18 is CMP polished to reduce the surface roughness of the p-type InGaN contact layer 18 to less than 1 nm, and a high-reflection film and an anti-reflection film are respectively evaporated on the reflection end face and the emission end face to obtain a GaAs-based edge emitting laser 22, the material of the high-reflection film is Ta2O5, and the material of the anti-reflection film can be CeF3;

[0131] S9: After the p-type InGa contact layer 18 is polished, the LNOI optical waveguide laser 21 is bonded to the p-type GaAs substrate 4, and the light outlet 23 of the GaAs basal edge emitting laser 22 is aligned with the end face 24 of the LNOI optical waveguide laser 21;

[0132] S10: sputter a p-side electrode 20 on the p-type GaAs substrate 4 and on the left side of the GaAs-based edge emitting laser 22, and sputter an n-side electrode 19 on the uppermost surface of the n-type GaAs substrate 4' of the GaAs-based edge emitting laser 22 to obtain a GaAs laser pumped lithium niobate waveguide photonic integrated device.

[0133] Experimental Example 1: Coupling efficiency test of GaAs laser-pumped LiNbO3 waveguide photonic integrated device obtained in Examples 1 to 4

[0134] A power meter is used to detect the output power of the GaAs fundamental edge emitting laser 22 in the GaAs laser pumped lithium niobate waveguide photonic integrated device obtained in Examples 1 to 4, and then the output power from the LNOI optical waveguide laser 21 is measured. By dividing the output power of the LNOI optical waveguide laser 21 by the output power of the GaAs fundamental edge emitting laser, the conversion efficiency of the device can be obtained.

[0135] from Figure 6 to Figure 9 It can be seen that the conversion efficiency of the GaAs laser pumped LiNbO3 waveguide photonic integrated device in Example 1 is 38% ( Figure 6 ), the conversion efficiency of the GaAs laser pumped LiNbO3 waveguide photonic integrated device in Example 2 is 41% ( Figure 7 ), the conversion efficiency of the GaAs laser pumped LiNbO3 waveguide photonic integrated device in Example 3 is 44% ( Figure 8 ), the conversion efficiency of the GaAs laser pumped LiNbO3 waveguide photonic integrated device in Example 4 is 46% ( Fig. 9 ), the higher the conversion efficiency of the integrated device, the better the coupling efficiency, which proves that the integrated device prepared in the embodiment of the present application has high coupling efficiency.

[0136] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A laser pumped lithium niobate waveguide photonic integrated device, characterized in that: The device is composed of a p-type substrate (4), an edge emitting laser (22), an LNOI optical waveguide laser (21), a p-side electrode (20) and an n-side electrode (19), wherein the p-side electrode (20), the bonded edge emitting laser (22) and the LNOI optical waveguide laser (21) are sputtered in sequence from left to right on the top of the p-type substrate (4), and the n-side electrode (19) is sputtered on the surface of the edge emitting laser (22); The LNOI optical waveguide laser (21) comprises, from top to bottom, a photoresist, a lithium niobate substrate (1) and a SiO2 layer (2); an ion implantation damage layer (3) is implanted into the lithium niobate substrate (1); a strip waveguide structure pattern (25) is etched on the surface of the lithium niobate substrate (1) through the photoresist; the strip waveguide structure pattern (25) contains a lithium niobate waveguide (7); a backward grating (10) and a forward grating (11) are etched into the lithium niobate substrate (1) through both ends of the strip waveguide structure pattern (25); rare earth ions are implanted into the lithium niobate substrate (1) so that the rare earth ions are dispersed in the lithium niobate substrate (1); and an end face (24) is provided on the left side; The edge emitting laser (22) is provided with a light outlet (23) on the right side, and the light outlet (23) faces the end face (24) in the LNOI optical waveguide laser (21), so that photons emitted by the edge emitting laser (22) due to energy level transition of laser-pumped rare earth ions are emitted in the forward grating (11) and the backward grating (10).

2. The photonic integrated device according to claim 1, characterized in that: The strip waveguide structure pattern (25) is, from left to right, a lithium niobate waveguide input end (9), a second tapered transition waveguide (8), a lithium niobate waveguide (7), a first tapered transition waveguide (6), and a lithium niobate waveguide output end (5); wherein the backward grating (10) is etched on the left side of the first tapered transition waveguide (6), and the forward grating (11) is etched on the right side of the second tapered transition waveguide (8).

3. The photonic integrated device according to claim 2, characterized in that: The length L2 of the lithium niobate waveguide (7) and the lithium niobate waveguide input end (9) is ≥20 μm, and the width w is 200 nm to 1000 nm. The length L1 of the first tapered transition waveguide (6) and the second tapered transition waveguide (8) is ≥20 μm, and the width M is 0.5 μm to 100 μm.

4. The photonic integrated device according to claim 1, characterized in that: The edge emitting laser (22) sputters the n-side electrode (19) in sequence from top to bottom, depositing an n-type substrate (4'), an n-type buffer layer (12), an n-type confinement layer (13), an n-type waveguide layer (14), a quantum well active region (15), a p-type waveguide layer (16), a p-type confinement layer (17) and a p-type contact layer (18).

5. The photonic integrated device according to claim 1, characterized in that: The rare earth ions are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium or yttrium ions.

6. The photonic integrated device according to claim 1, characterized in that: The substrates in the p-type substrate (4) and the n-type substrate (4') are gallium arsenide substrates, silicon substrates, sapphire substrates, diamond substrates, gallium nitride substrates, silicon carbide substrates or indium phosphide substrates.

7. The photonic integrated device according to claim 1, characterized in that: The thickness of the lithium niobate substrate (1) is 0.1-10 μm.

8. The method for preparing an integrated device according to any one of claims 1 to 7, characterized in that: The steps include: S1. Depositing a SiO2 layer (2) on a lithium niobate substrate (1) by plasma chemical vapor deposition or magnetron sputtering, and injecting helium ions into the lithium niobate substrate (1) through the SiO2 layer (2) by ion implantation to form an ion implantation damage layer (3); S2. The surface of the SiO2 layer (2) is polished by a chemical mechanical polishing process to reduce the surface roughness of the SiO2 layer (2) to less than 1 nm, and then bonded to a p-type substrate (4) to obtain a wafer bonding pair. The bonding process is as follows: first, the p-type substrate (4) and the surface of the SiO2 layer (2) are bombarded and activated by plasma, and then the p-type substrate (4) is bonded to the SiO2 layer (2) to obtain a wafer bonding pair. S3. Annealing the wafer bonding pair to peel off the lithium niobate substrate (1) above the ion implantation damaged layer (3). After the peeling is completed, polishing the lithium niobate substrate (1). After polishing, rare earth ions are injected into the lithium niobate substrate (1); S4. coating a layer of photoresist on the polished lithium niobate substrate (1), then exposing the surface of the photoresist, transferring the strip waveguide structure pattern (25) to the photoresist by photolithography, and then etching the strip waveguide structure pattern (25) onto the lithium niobate substrate (1) by electron beam lithography combined with an inductively coupled plasma etcher; S5. Using a femtosecond laser to pass through the strip waveguide structure pattern (25), a backward grating (10) and a forward grating (11) are etched in the lithium niobate substrate (1) to obtain a LNOI optical waveguide laser (21); S6. epitaxially growing an n-type buffer layer (12), an n-type confinement layer (13), an n-type waveguide layer (14), a quantum well active region (15), a p-type waveguide layer (16), a p-type confinement layer (17) and a p-type contact layer (18) on an n-type substrate (4') in sequence by metal organic chemical vapor deposition. After the epitaxial growth is completed, the p-type contact layer (18) is polished to reduce the surface roughness of the p-type contact layer (18) to less than 1 nm. A high reflection film and an anti-reflection film are respectively evaporated on the reflection end face and the emission end face to obtain an edge emitting laser (22); S7. Bond an edge emitting laser (22) to a p-type substrate (4), with the light outlet (23) of the edge emitting laser (22) aligned with the end face (24) of the LNOI optical waveguide laser (21); sputter a p-side electrode (20) on the p-type substrate, and sputter an n-side electrode (19) on the n-type substrate.

9. The preparation method according to claim 8, characterized in that: In step S4, during the photolithography, a mask is placed on the lithium niobate substrate, and after the photolithography is completed, development and hardening are performed to finally form a ridge waveguide.

10. Use of the photonic integrated device according to any one of claims 1 to 7 as a chip.

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