Organic polymer all-optical interlayer coupler based on buried graphene heater and preparation method thereof

Abstract

The invention discloses an organic polymer all-optical interlayer coupler based on a buried graphene heater and a preparation method of the organic polymer all-optical interlayer coupler, and belongs to the field of integrated optoelectronic devices. Comprising a substrate, a lower cladding, a lower polymer upper cladding and an upper polymer upper cladding which are sequentially arranged from bottom to top, the lower polymer upper cladding wraps the lower rectangular structure optical waveguide core layer, and the lower rectangular structure optical waveguide core layer is located on the upper surface of the lower cladding; a graphene layer is embedded in the center of the lower rectangular structure optical waveguide core layer, and the width of the graphene layer is equal to that of the lower rectangular structure optical waveguide core layer; the upper polymer upper cladding wraps the upper rectangular structure optical waveguide core layer, and the upper rectangular structure optical waveguide core layer is located on the upper surface of the lower polymer upper cladding. By utilizing the photothermal effect and light absorption polarization sensitivity of graphene, pump light (TE mode) is absorbed to generate a thermal field, and interlayer coupling transmission regulation and control on signal light (TM mode) in the waveguide are realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of integrated optoelectronic devices, and particularly relates to an organic polymer full-optical interlayer coupler based on a buried graphene heater and a preparation method thereof. BACKGROUND

[0002] To meet the urgent needs of information density and network bandwidth in the fields of large-capacity optical communication and high-performance computing, the improvement of the integration and scalability of photonic integrated systems as a key supporting platform has become a technical challenge to be broken through. However, the preparation of current optical waveguide unit devices mainly depends on two-dimensional planar semiconductor processing technology, and the optical transmission is limited in a single layer plane. Limited by the optical diffraction effect, the integration scale of the devices on the chip is restricted by the chip area and is difficult to continue to improve. To break through the physical limitations of traditional two-dimensional photonic integration technology and further improve the information capacity and bandwidth of optical communication systems, three-dimensional photonic integration technology has become the most potential technical route for the next generation of high-performance photonic integrated systems because it can realize multi-layer optical interconnection network on the chip. Three-dimensional photonic integration technology starts from the spatial dimension, adopts a multi-layer photonic device stacking and optical interconnection architecture in the vertical dimension, significantly improves the chip integration and scalability by constructing a three-dimensional optical signal transmission and processing network, and realizes a high-density, multi-functional integrated photonic chip system.

[0003] In a three-dimensional photonic integrated chip system, an interlayer coupler as a core functional unit plays a key role in realizing optical signal transmission and routing switching across layers, and can complete the optical signal interconnection between different plane waveguide layers in a low-loss and high-efficiency manner. At present, the interlayer coupler based on the principle of evanescent field coupling has become one of the main solutions in three-dimensional photonic integrated systems. By converting a stable waveguide optical field into an evanescent wave field and entering the cladding, and then coupling to the next layer waveguide and gradually converting into a stable waveguide optical field, the optical transmission between different layers of waveguides is realized. In addition, by introducing external excitation control means such as electro-optic and thermo-optic, the coupling coefficient and phase matching condition between waveguides can be dynamically adjusted, so as to realize controllable routing and selective transmission of optical signals between specific waveguide layers. Although the interlayer interconnection technology based on evanescent field coupling has the advantages of compact structure, high coupling efficiency and good process compatibility, it still faces important challenges in practical applications. In particular, when dealing with the interlayer signal coupling control of multiple input channels, the arrangement scheme and voltage application strategy of the interlayer electrodes need to be carefully designed. This design must take into account two key factors: ensuring accurate control of the target waveguide layer and minimizing signal interference of adjacent waveguide layers. This complex electrode layout not only increases the process difficulty, but also restricts the density improvement of three-dimensional photonic integrated systems. SUMMARY

[0004] The present application provides an organic polymer all-optical interlayer coupler based on a buried graphene heater and a preparation method thereof.

[0005] The present application provides an organic polymer all-optical interlayer coupler based on a buried graphene heater, which comprises a substrate, a lower cladding, a lower-layer polymer upper cladding, and an upper-layer polymer upper cladding arranged in sequence from bottom to top.

[0006] Further, the substrate is a silicon wafer with a width of 1-3 mm and a thickness of 300-800 μm; the lower cladding is silicon dioxide with a width of 1-3 mm and a thickness of 3-7 μm; and the graphene layer is single-layer graphene with a thickness of 0.35-0.7 nm and a width of 2-4 μm.

[0007] Further, the upper-layer polymer upper cladding and the lower-layer polymer upper cladding are made of the same material, which is one of EpoCore, EpoClad, polymethyl methacrylate, glycidyl methacrylate copolymer, polyethylene, polyester, and polystyrene; the lower-layer polymer upper cladding has a width of 1-3 mm and a thickness of 3-5 μm; and the upper-layer polymer upper cladding has a width of 1-3 mm and a thickness of 5-10 μm.

[0008] Further, the upper-layer rectangular structure optical waveguide core layer and the lower-layer rectangular structure optical waveguide core layer are made of the same material, which is one of SU-82002, SU-82005, polycarbonate, and polyimide, and supports TE and TM modes, and has a width of 2-4 μm and a thickness of 2-4 μm; the distance between the upper-layer rectangular structure optical waveguide core layer and the lower-layer rectangular structure optical waveguide core layer is 1-2 μm.

[0009] The present application also provides a preparation method of the organic polymer all-optical interlayer coupler based on a buried graphene heater, which comprises the following steps.

[0010] Step 1: pretreatment of the substrate layer of silicon wafer;

[0011] Step 2: growing a lower silica cladding layer by a method of alternating dry and wet oxidation;

[0012] Step 3: spin-coating a polymer material, etching the spin-coating process to make a lower rectangular structure optical waveguide core layer I; spin-coating a polymer core layer material on the cleaned lower cladding layer to make a polymer core layer with a thickness of 2-3 μm; after being cooled to room temperature, using an inductively coupled plasma etching machine to etch the polymer core layer to a thickness of 1-2 μm, thereby making an optical waveguide core layer I on the silica layer;

[0013] Step 4: transferring and making a graphene layer on the lower rectangular structure optical waveguide core layer I; first transferring a single-layer graphene with a PMMA support layer to the surface of the lower rectangular structure optical waveguide core layer I, baking at 70-100°C to make the graphene layer (3) closely adhere to the lower rectangular structure optical waveguide core layer I; placing in an acetone solution to remove the polymer PMMA support layer above the graphene layer, using deionized water to remove residual acetone solution, and then baking at 70-140°C, thereby obtaining a single-layer graphene;

[0014] Step 5: making a lower rectangular structure optical waveguide core layer; spin-coating a polymer core layer material on the graphene layer, the spin-coating method being the same as in Step 3; using a mask to perform photolithography under a photolithography machine, the shape of the mask being a rectangular structure of the optical waveguide core layer to be made; after photolithography, heating the device at 60-65°C for 10-15 min and at 95-100°C for 20-30 min, then immersing it in a special developing solution for the polymer core layer material for 30-40 seconds, the unexposed polymer core layer material blocked by the mask being etched away; then placing it in an isopropyl alcohol solution to remove residual developing solution, repeatedly rinsing with deionized water to remove residual liquid, using an ear cleaning ball to blow dry the surface liquid, and then placing it at 120-130°C for 20-30 min for post-baking, thereby making a lower rectangular structure optical waveguide core layer on the silica lower cladding layer;

[0015] Step 6: making a lower polymer upper cladding layer by a spin-coating process; spin-coating a polymer upper cladding layer material on the lower cladding layer and the lower rectangular structure optical waveguide core layer to make a thickness of 5-10 μm; using an inductively coupled plasma etching machine to etch the polymer lower cladding layer to a thickness of 3 μm;

[0016] Step 7: the upper polymer overcladding layer and the upper rectangular structure optical waveguide core layer are prepared on the polymer overcladding layer by using a spin coating process combined with an inductively coupled plasma etching machine; first, the rectangular structure optical waveguide core layer material is spin coated on the polymer overcladding layer (4) by using a spin coating process, then photolithography is performed under a photoetching machine by using a mask, and finally, the polymer overcladding layer material is spin coated to prepare a polymer overcladding layer with a thickness of 5-10 microns, so that the organic polymer all-optical interlayer coupler based on the buried graphene heater is prepared.

[0017] Further, in step 1, the substrate layer silicon wafer pretreatment specifically comprises: first, placing the cleaved silicon wafer in an acetone solution and ultrasonically oscillating for 15-20 min, then wiping the surface of the silicon wafer with cotton balls soaked with acetone and ethanol in sequence, then rinsing the surface of the silicon wafer with deionized water and blowing the deionized water on the surface of the silicon wafer with nitrogen, and finally baking at 120-150 DEG C for 1.5-2 h to remove the residual water vapor on the surface of the silicon wafer.

[0018] Further, in step 2, the oxidation temperature is 1100-1300 DEG C; first, dry oxygen oxidation is performed for 20-40 min, and then wet oxygen oxidation and dry oxygen oxidation are alternately performed for 5-8 times; the wet oxygen oxidation and dry oxygen oxidation are alternately performed as follows: when the wet oxygen oxidation is performed, the flow rate of water vapor is 5-15 slm and the flow rate of oxygen is 0.3-1.5 slm, and the wet oxygen oxidation is performed for 50-70 min; when the dry oxygen oxidation is performed, only oxygen is introduced, the flow rate is 3-10 slm, and the dry oxygen oxidation is performed for 20-40 min, so as to obtain a silicon dioxide lower cladding layer with a thickness of 300-800 microns.

[0019] Further, when the upper rectangular structure optical waveguide core layer material and the lower rectangular structure optical waveguide core layer material are spin coated, the spin coating speed is 2000-3000 r / min, and then the materials are pre-baked at 50-65 DEG C for 10-15 min and at 90-100 DEG C for 20-30 min, and then the materials are middle-baked at 50-65 DEG C for 10-15 min and at 90-100 DEG C for 20-30 min.

[0020] Further, when the upper polymer overcladding layer material and the lower polymer overcladding layer material are spin coated, the spin coating speed is 3000-4000 r / min, and then the materials are baked at 120-150 DEG C for 2.5-3 h.

[0021] The present application has the following advantages:

[0022] The organic polymer all-optical interlayer coupler based on the buried graphene heater of the application adopts polymer material to design a waveguide structure, graphene as a heater is buried in the center position inside the lower waveguide, the coupling distance and the coupling length of the coupling area are optimized, heat is generated by absorbing pump light, the transmission of signal light in different waveguide layers is regulated, the advantages of polymer material, such as various types, easy to prepare and process, are fully utilized, and the preparation process is easier to realize, and the preparation process is compatible with the traditional CMOS process and easy to integrate.

[0023] The application can greatly expand the integration degree and application scenarios of polymer photon integrated devices, and make the selection and regulation of multiple signal channels in a three-dimensional integrated structure more flexible. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the organic polymer all-optical interlayer coupler based on the buried graphene heater of the application; wherein, Fig. (a) is a schematic diagram of the cross-sectional structure of the coupling area, and Fig. (b) is a side view of the coupler;

[0025] Figure 2 It is a simulation diagram of the TE mode (pump light) and TM mode (signal light) light field distribution of the organic polymer all-optical interlayer coupler of the buried graphene heater of the application at different wavelengths;

[0026] Figure 3 It is a simulation diagram of the thermal field distribution of the organic polymer all-optical interlayer coupler based on the buried graphene heater of the application;

[0027] Figure 4 It is a curve of the change relationship between the coupling efficiency of the coupling area of the organic polymer all-optical interlayer coupler of the buried graphene heater of the application and the coupling length;

[0028] Figure 5 It is a simulation diagram of the transmission of the optical signal of the coupling area of the organic polymer all-optical interlayer coupler of the buried graphene heater of the application; wherein, Fig. (a) is a simulation diagram of the transmission of the optical signal of the coupling area when there is no input of pump light, and Fig. (b) is a simulation diagram of the transmission of the optical signal of the coupling area when pump light is input;

[0029] Figure 6 It is a process preparation flowchart of the organic polymer all-optical interlayer coupler based on the buried graphene heater of the application; wherein, Fig. (a) is a process preparation flowchart of the organic polymer all-optical interlayer coupler, and Fig. (b) is a graphene transfer process flowchart. DETAILED DESCRIPTION

[0030] The application will be further described below with reference to the drawings.

[0031] Example 1

[0032] An organic polymer all-optical interlayer coupler based on a buried graphene heater is capable of interlayer coupling transmission modulation of signal light (TM mode) in a waveguide, such as... Figure 1 As shown, the device comprises a substrate 1, a silicon dioxide lower cladding layer 2, a graphene layer 3, a lower polymer upper cladding layer 4, an upper polymer upper cladding layer 5, an upper rectangular optical waveguide core layer 6, and a lower rectangular optical waveguide core layer 7. The widths (x-direction) of the lower polymer upper cladding layer 4 and the upper polymer upper cladding layer 5 are equal to the width of the silicon dioxide lower cladding layer 2. The lower rectangular optical waveguide core layer 7 is located in the middle of the lower polymer upper cladding layer 4, and the upper rectangular optical waveguide core layer 6 is located in the middle of the upper polymer upper cladding layer 5. The graphene layer 3 is disposed at the horizontal midpoint of the lower rectangular optical waveguide core layer 7, with the same width as the optical waveguide core layer 7. This organic polymer all-optical interlayer coupler can perform interlayer coupling transmission modulation of the signal light (TM mode) in the waveguide.

[0033] A silicon wafer is used as the substrate layer 1, with a thickness of 500 μm and a width of 1.9 mm; silicon dioxide is used as the lower cladding layer 2, with a thickness of 4 μm and a width of 1.9 mm; the lower polymer upper cladding layer 4 and the upper polymer upper cladding layer 5 are made of low-refractive-index polymer material, specifically P(MMA-co-GMA); the lower polymer upper cladding layer 4 has a thickness of 3 μm and a width of 1.9 mm, the same as the substrate layer width; the upper polymer upper cladding layer 5 has a thickness of 10 μm and a width of 1.9 mm, the same as the substrate layer width; the lower rectangular waveguide core layer 7 is made of SU-82002 material; the lower rectangular waveguide core layer 7 has a thickness of 2 μm and a width of 2 μm; the lower rectangular structure... The optical waveguide core layer 7 is located at the upper-middle position in the x-direction of the lower polymer cladding layer 4; the lower rectangular optical waveguide core layer 6 has the same parameters as the lower rectangular optical waveguide core layer 7 and is located at the upper-middle position in the x-direction of the upper polymer cladding layer 5; the graphene is a single layer of graphene with a thickness of 0.7 nm and the same width as the rectangular optical waveguide core layer; placing the graphene heater inside the lower rectangular optical waveguide core layer 7 achieves interlayer selective transmission control of the signal light. The graphene layer absorbs the pump light (TE mode) and generates heat to control the signal light in the waveguide (TM mode), changing the refractive index of the lower rectangular optical waveguide core layer 7, resulting in a change in the interlayer coupling efficiency, thus achieving interlayer selective transmission control.

[0034] like Figure 2As shown, the simulation diagrams of the TE mode optical field distribution and the TM mode optical field distribution of the organic polymer all-optical interlayer coupler based on a buried graphene heater, simulated using COMSOL software, are displayed at a wavelength of 980 nm and 1550 nm, respectively. The diagrams show that the TE mode optical field has a good shape, with the strongest light field located at the center of the waveguide core layer; the TM mode optical field also has a good shape, with the strongest light field located above and below the waveguide core layer. The waveguide effectively confines the modes, avoiding crosstalk during coupling. Combining the light absorption polarization sensitivity and photothermal properties of graphene, it can be seen that when graphene is placed at the center of the lower waveguide core layer, it can interact strongly with the TE mode, while exhibiting low light absorption loss for the TM mode. This allows the absorption of heat from the TE mode to regulate the transmission of the TM mode within a specific waveguide layer.

[0035] like Figure 3 The figure shows a simulation of the thermal field distribution of an organic polymer all-optical interlayer coupler based on a buried graphene heater, using Lumerical software. The figure shows that the heat generated by the graphene heater in the lower waveguide core layer is mainly concentrated in the lower waveguide, with minimal impact on the upper waveguide, and exhibits high heating efficiency, averaging 4K temperature increase per 1mW.

[0036] like Figure 4 The figure shows the relationship between coupling efficiency and coupling length in the coupling region of an organic polymer all-optical interlayer coupler based on a buried graphene heater, simulated using Lumerical software. It can be seen from the figure that when the coupling spacing is 1 μm, a coupling length of approximately 126 μm is required to couple 97% of the energy in the lower waveguide to the upper waveguide, completing one coupling operation.

[0037] like Figure 5 As shown in (a), this is a simulation diagram of the transmission of optical signals in the coupling region of an organic polymer all-optical interlayer coupler based on a buried graphene heater, simulated using Lumerical software, without pump light input. The diagram shows that, without pump light input, the optical signal input from the lower waveguide is coupled to the upper waveguide with a fixed coupling efficiency for transmission in the coupling region. Figure 5 (b) shows a transmission simulation diagram when the pump light is input. As can be seen from the diagram, the signal light in the lower waveguide does not undergo coupling when passing through the coupling region, and is thus output from the lower waveguide output end.

[0038] Example 2

[0039] Combined with appendix Figure 6 The detailed fabrication process of the organic polymer all-optical interlayer coupler based on a buried graphene heater in this embodiment is described in detail below. The fabrication steps are as follows:

[0040] 1. Cleaning treatment of substrate layer silicon wafer: first, cleaved silicon wafer is placed in acetone solution and ultrasonically vibrated for 15-20 min, then the surface of the silicon wafer is wiped with cotton balls soaked with acetone and ethanol in sequence, after that the surface of the silicon wafer is rinsed with deionized water, and the deionized water on the surface of the silicon wafer is blown dry with nitrogen, finally the silicon wafer is baked at 120-150℃ for 1.5-2h to remove the residual water vapor on the surface of the silicon wafer;

[0041] 2. Growth of silicon dioxide undercladding layer 2: dry oxygen oxidation and wet oxygen oxidation are alternately performed to grow the silicon dioxide layer, and the oxidation temperature is maintained at 1200℃; first dry oxygen oxidation is performed for 25 min, then wet oxygen oxidation and dry oxygen oxidation are alternately performed for 7 times; wherein the flow rate of water vapor is 11 slm and the flow rate of oxygen is 0.6 slm during wet oxygen oxidation, and the time of wet oxygen oxidation is 60 min; only oxygen is introduced during dry oxygen oxidation, and the flow rate is 5 slm, and the time of dry oxygen oxidation is 30 min, thereby obtaining a silicon dioxide undercladding layer 2 with a thickness of 4μm;

[0042] 3. Preparation of lower layer rectangular structure optical waveguide core layer I by spin coating process: the polymer core layer material is spin-coated on the cleaned lower cladding layer 2 at a spin-coating speed of 2500r / min, and then pre-baking is performed at 65℃ for 10 min and at 95℃ for 20 min, and then middle baking is performed at 65℃ for 10 min and at 95℃ for 20 min, thereby preparing an optical waveguide core layer with a thickness of 2μm; after cooling to room temperature, the thickness of the optical waveguide core layer is etched to 1μm by using an inductively coupled plasma etching machine, thereby preparing a rectangular structure polymer core layer I on the silicon dioxide undercladding layer 2;

[0043] 4. Transfer and preparation of graphene layer 3 on the lower layer rectangular structure optical waveguide core layer I: first, the purchased commercial single-layer graphene (with PMMA support layer) is transferred to the surface of the polymer core layer I; baking is performed at 90℃ to make the graphene layer 3 closely adhere to the polymer core layer 7'; then, the polymer PMMA support layer is removed by placing in acetone solution, the residual acetone solution is removed with deionized water, and baking is performed at 110℃, thereby obtaining a single-layer graphene 3;

[0044] 5. The lower layer of the rectangular structure of the optical waveguide core layer 7 is prepared by the wet etching process: the same preparation method as the optical waveguide core layer 7' is used to prepare the optical waveguide core layer II on the graphene layer 3; the photolithography is performed using a mask in the photoetching machine, the shape of the mask is the rectangular structure of the optical waveguide core layer 7 to be prepared; after the photolithography, the device is heated at 65℃ for 10 min and at 95℃ for 20 min, and then is immersed in a special developing solution for polymer core layer material for 40 seconds, the unexposed polymer core layer material blocked by the mask is etched away; then it is placed in an isopropanol solution to remove the residual developing solution, and then is repeatedly rinsed with deionized water to remove the residual liquid, and is placed in a 120℃ condition for 30 min after baking to prepare the lower layer of the rectangular structure of the optical waveguide core layer 7 on the silica lower cladding layer 2;

[0045] 6. The lower layer of the polymer upper cladding layer 4 is prepared by the spin coating process: the polymer upper cladding material is spin-coated on the polymer core layer 7 by the spin coating process at a speed of 3000 r / min, and then is baked at 120℃ for 2.5 h to prepare a polymer upper cladding layer 4' with a thickness of 5 μm; the thickness of the lower layer of the polymer upper cladding layer 4 is etched to 3 μm by an inductively coupled plasma etching machine;

[0046] 7. The upper layer of the polymer upper cladding layer 5 and the upper layer of the rectangular structure of the optical waveguide core layer 6 are prepared on the polymer upper cladding layer 4 by the spin coating process combined with the inductively coupled plasma etching machine: first, the rectangular structure of the optical waveguide core layer material is spin-coated on the polymer upper cladding layer 4 by the spin coating process, then the photolithography is performed using a mask in the photoetching machine, and finally the polymer upper cladding material is spin-coated to prepare a polymer upper cladding layer 5 with a thickness of 5-10 μm, thereby preparing an organic polymer all-optical interlayer coupler based on a buried graphene heater.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An organic polymer all-optical interlayer coupler based on a buried graphene heater, characterized by, It comprises, from bottom to top, a substrate (1), a lower cladding layer (2), a lower polymer upper cladding layer (4), and an upper polymer upper cladding layer (5); the lower polymer upper cladding layer (4) is wrapped around a lower rectangular structure optical waveguide core layer (7), and the lower rectangular structure optical waveguide core layer (7) is located on the upper surface of the lower cladding layer (2); a graphene layer (3) is embedded in the center of the lower rectangular structure optical waveguide core layer (7), and the width of the graphene layer (3) is equal to that of the lower rectangular structure optical waveguide core layer (7); the upper polymer upper cladding layer (5) is wrapped around an upper rectangular structure optical waveguide core layer (6), and the upper rectangular structure optical waveguide core layer (6) is located on the upper surface of the lower polymer upper cladding layer (4).

2. The all-organic polymer OPL-IOL coupler based on the buried graphene heater according to claim 1, wherein, The substrate (1) is a silicon wafer with a width of 1-3 mm and a thickness of 300-800 μm; the lower cladding layer (2) is silicon dioxide with a width of 1-3 mm and a thickness of 3-7 μm; and the graphene layer (3) is single-layer graphene with a thickness of 0.35-0.7 nm and a width of 2-4 μm. 3.The organic polymer all-optical interlayer coupler based on the buried graphene heater according to claim 1, wherein, The upper polymer upper cladding layer (5) and the lower polymer upper cladding layer (4) are made of the same material, which is one of EpoCore, EpoClad, polymethyl methacrylate, glycidyl methacrylate copolymer, polyethylene, polyester, and polystyrene; the lower polymer upper cladding layer (4) has a width of 1-3 mm and a thickness of 3-5 μm; and the upper polymer upper cladding layer (5) has a width of 1-3 mm and a thickness of 5-10 μm.

4. The all-organic polymer OPL-IOL based on the buried graphene heater according to claim 1, wherein, The upper rectangular structure optical waveguide core layer (6) and the lower rectangular structure optical waveguide core layer (7) are made of the same material, which is one of SU-82002, SU-82005, polycarbonate, and polyimide, and supports TE and TM modes; the width of the upper rectangular structure optical waveguide core layer (6) and the lower rectangular structure optical waveguide core layer (7) is 2-4 μm, and the thickness is 2-4 μm; and the distance between the upper rectangular structure optical waveguide core layer (6) and the lower rectangular structure optical waveguide core layer (7) is 1-2 μm.

5. A method for fabricating an organic polymer all-optical interlayer coupler based on a buried graphene heater according to claim 1, characterized in that, It comprises: Step 1: pretreatment of the substrate layer (1) of silicon wafer; Step 2: growth of the lower cladding layer (2) of silicon dioxide by using a method of alternating dry oxygen oxidation and wet oxygen oxidation; Step 3: etching of the lower rectangular structure optical waveguide core layer I by using a method of spin-coating polymer material and etching spin-coating process; the rectangular structure optical waveguide core layer material is spin-coated on the cleaned lower cladding layer (2) to prepare a polymer core layer with a thickness of 2-3 μm; after being cooled to room temperature, the thickness of the polymer core layer is etched to 1-2 μm by using an inductively coupled plasma etching machine, thereby preparing the optical waveguide core layer I on the silicon dioxide layer; Step 4: transferring graphene layer (3) on the lower rectangular structure optical waveguide core layer I; firstly, single-layer graphene with PMMA support layer is transferred to the surface of the lower rectangular structure optical waveguide core layer I, and baking is performed at 70-100℃ to make the graphene layer (3) closely adhere to the lower rectangular structure optical waveguide core layer I; the polymer PMMA support layer above the graphene layer (3) is removed by placing in acetone solution, residual acetone solution is removed with deionized water, and then baking is performed at 70-140℃, thereby obtaining single-layer graphene (3); Step 5: preparing the lower rectangular structure optical waveguide core layer (7); spin-coating polymer core layer material on the graphene layer (3), the spin-coating mode is the same as that in step 3; using a mask plate for photolithography under a photoetching machine, the shape of the mask plate is the rectangular structure of the optical waveguide core layer (7) to be prepared; after photolithography, the device is heated at 60-65℃ for 10-15 minutes and at 95-100℃ for 20-30 minutes, and then is immersed in a special developing solution for polymer core layer material for 30-40 seconds, the unexposed polymer core layer material blocked by the mask plate is etched away; then it is placed in isopropyl alcohol solution to remove residual developing solution, and then is repeatedly rinsed with deionized water to remove residual liquid, and is blown dry with ear bulb after the surface liquid is removed, and then is placed at 120-130℃ for 20-30 minutes for post-baking, thereby preparing the lower rectangular structure optical waveguide core layer (7) on the silica lower cladding layer (2); Step 6: preparing the lower polymer upper cladding layer (4) by spin-coating process; spin-coating polymer upper cladding material on the lower cladding layer (2) and the lower rectangular structure optical waveguide core layer (7) to prepare a thickness of 5-10μm; using an inductively coupled plasma etching machine to etch the thickness of the lower polymer upper cladding layer (4) to 3μm; Step 7: preparing the upper polymer upper cladding layer (5) and the upper rectangular structure optical waveguide core layer (6) on the polymer upper cladding layer (4) by spin-coating process combined with an inductively coupled plasma etching machine; firstly, spin-coating rectangular structure optical waveguide core layer material on the polymer upper cladding layer (4), then using a mask plate for photolithography under a photoetching machine, and finally spin-coating polymer upper cladding material to prepare a polymer upper cladding layer (5) with a thickness of 5-10μm, thereby preparing an organic polymer full optical interlayer coupler based on a buried graphene heater.

6. The method of claim 5, wherein the buried graphene heater-based organic polymer all-optical interlayer coupler is prepared by the steps of: (a) preparing a graphene heater on a substrate; (b) depositing a first organic polymer layer on the graphene heater; (c) depositing a second organic polymer layer on the first organic polymer layer; and (d) depositing a third organic polymer layer on the second organic polymer layer. In step 1, the substrate layer silicon wafer pretreatment is specifically as follows: firstly, the cleaved silicon wafer is placed in acetone solution and ultrasonically vibrated for 15-20min, then the silicon wafer surface is wiped with cotton balls soaked with acetone and ethanol in sequence, then the silicon wafer surface is rinsed clean with deionized water, and the deionized water on the silicon wafer surface is blown dry with nitrogen, and finally the silicon wafer is baked at 120-150℃ for 1.5-2h to remove residual water vapor on the silicon wafer surface.

7. The method of claim 5, wherein the buried graphene heater is formed by a process comprising: forming a graphene layer on a substrate; forming a first metal layer on the graphene layer; forming a second metal layer on the first metal layer; and forming a third metal layer on the second metal layer. In step 2, the oxidation temperature is 1100-1300℃; first dry oxygen oxidation is performed for 20-40 min, then wet oxygen oxidation and dry oxygen oxidation are alternately performed for 5-8 times; the wet oxygen oxidation and dry oxygen oxidation are alternately performed as follows: the flow rate of water vapor is 5-15 slm and the flow rate of oxygen is 0.3-1.5 slm during the wet oxygen oxidation, and the time of the wet oxygen oxidation is 50-70 min; only oxygen is introduced during the dry oxygen oxidation, and the flow rate of oxygen is 3-10 slm, and the time of the dry oxygen oxidation is 20-40 min, to obtain the lower silica cladding layer (2) with a thickness of 300-800 μm.

8. The method for fabricating an organic polymer all-optical interlayer coupler based on a buried graphene heater according to claim 5, characterized in that, When the upper layer of rectangular structure optical waveguide core layer material and the lower layer of rectangular structure optical waveguide core layer material are spin-coated, the spin-coating speed is 2000-3000 r / min, then pre-baking is performed at 50-65℃ for 10-15 min and at 90-100℃ for 20-30 min, and then middle-baking is performed at 50-65℃ for 10-15 min and at 90-100℃ for 20-30 min.

9. The method for fabricating an organic polymer all-optical interlayer coupler based on a buried graphene heater according to claim 5, characterized in that, When the upper layer of polymer upper cladding layer material and the lower layer of polymer upper cladding layer material are spin-coated, the spin-coating speed is 3000-4000 r / min, and then baking is performed at 120-150℃ for 2.5-3 h.

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