Multichannel optical power divider based on MMI structure and preparation method thereof

Abstract

The invention discloses a multi-channel optical power divider based on an MMI structure and a preparation method thereof, and belongs to the technical field of planar optical waveguide devices and preparation thereof. The polymer optical waveguide is composed of a silicon wafer substrate, a polymer lower cladding, a polymer optical waveguide core layer of a strip-shaped structure and a polymer upper cladding in sequence from bottom to top, and the polymer optical waveguide core layer of the strip-shaped structure is based on an MMI structure and is wrapped in the polymer upper cladding. According to the waveguide type power divider, the characteristics of large process tolerance and small size of an MMI optical waveguide structure are combined, and the advantage of various types of organic polymer materials is also utilized, so that the purpose of performing same power distribution on input of a plurality of different ports is realized; besides, the process for preparing the device by adopting the polymer material is relatively simple, only conventional processes such as spin coating and photoetching are needed, the process with relatively high difficulty is not needed, the production cost is low, the efficiency is high, large-scale batch production can be realized, and the power divider can be applied to practice.

Description

Technical Field

[0001] The present invention belongs to the technical field of planar optical waveguide devices and preparation thereof, and specifically relates to a multi-channel optical power distributor based on an MMI structure with Si as a substrate and organic polymer materials as waveguide core layers and claddings, and a preparation method thereof. Background Art

[0002] As the core device of optical communication system and on-chip optical interconnect chip, the optical power divider is used to evenly distribute the input optical signal power to several output ports, so as to realize the distribution and synthesis of optical signals. It is the basic element of optical switch, optical modulator, multiplexer and demultiplexer. Among them, the optical power divider based on planar optical waveguide structure can divide an input signal into multiple output signals to meet specific application requirements. It is not only well compatible with optical fiber, but also has the advantages of compact structure, tunability, low insertion loss and flexible design. Most of the current optical power dividers are single-end input and multi-end output structures, such as the common 1×3, 1×6 and 1×N structures. These structures have played an important role in the development of optical communication in the past. They can meet the distribution requirements of optical signals to a certain extent, so that optical signals can be transmitted from one input port to multiple output ports, realize simple optical signal diversion, and provide support for the basic function realization of optical communication system.

[0003] However, this traditional structure of optical power divider has obvious limitations. From the perspective of input port design, this single-ended input design limits its functional expansion. It can only process optical signal input from a single channel and cannot meet the power distribution requirements of multiple input signals at the same time. In optical communication networks, this limitation leads to the inability of optical power dividers to efficiently and reasonably distribute multiple input optical signals in complex environments with multiple optical signal sources, which severely limits the flexibility of optical communication networks and the entire system. This makes optical communication systems unable to cope with complex business scenarios and multiple signal source access, affecting the adaptability and scalability of optical communication systems.

[0004] In order to meet the urgent demand for flexibility in modern communication networks, it is urgent to break the limitations of traditional optical power dividers in the design of input and output ports, design an optical power divider that can achieve multi-segment input and multi-segment output, overcome the limitations of traditional structures, and adapt to the complex and diverse usage environment of modern communication networks, providing strong support for the further development of optical communication systems. Summary of the invention

[0005] In order to overcome the shortcomings of traditional optical power dividers, the object of the present invention is to provide a multi-channel optical power divider based on an MMI structure with multi-port input and multi-port output and a preparation method thereof.

[0006] The present invention uses silicon as the waveguide substrate, organic polymer materials as the upper and lower claddings of the optical waveguide, and the core layer of the polymer optical waveguide uses organic polymer materials with different refractive indices. This design makes full use of the diversity, excellent processing performance and low cost of existing polymer materials. The preparation process is simple and easy, compatible with semiconductor processes, easy to integrate, and suitable for large-scale production. Therefore, the invention has important application value in the field of optical communications and planar optical waveguide power dividers.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0008] A multi-channel optical power distributor based on an MMI structure is composed of a silicon wafer substrate 51, a polymer lower cladding 52, a strip-shaped polymer optical waveguide core layer 53 and a polymer upper cladding 54 from bottom to top, wherein the strip-shaped polymer optical waveguide core layer 53 is coated in the polymer upper cladding 54; wherein the strip-shaped polymer optical waveguide core layer 53 is based on an MMI structure, as shown in the attached Figure 1As shown, from left to right along the propagation direction of light, there are successively a first input straight waveguide 1, a second input straight waveguide 2, and a third input straight waveguide 3 with the same structure and size, a first S-bent waveguide 4 and a second S-bent waveguide 6 with the same structure and size, a first straight waveguide 5, a first input tapered waveguide 7, a second input tapered waveguide 8, and a third input tapered waveguide 9 with the same structure and size, a first multimode interference waveguide 10, a first output tapered waveguide 11, a second output tapered waveguide 12, and a third output tapered waveguide 13 with the same structure and size, a third S-bent waveguide 14 and a fourth S-bent waveguide 16 with the same size and size, a second straight waveguide 15, a third straight waveguide 17 and a fourth straight waveguide 18 with the same structure and size, a fourth input tapered waveguide 19, a second multimode interference waveguide 20, a fourth output tapered waveguide 21 and a fifth output tapered waveguide 22 with the same structure and size, a fifth S-bent waveguide 23 and an eighth S-bent waveguide 26 with the same structure and size, and a sixth S-bent waveguide 27 with the same structure and size. The curved waveguide 24 and the seventh S-curved waveguide 25, the fifth input tapered waveguide 27, the sixth input tapered waveguide 28, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 having the same structure and size, the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 having the same structure and size, the sixth output tapered waveguide 33, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36 and the eleventh output tapered waveguide 38 having the same structure and size, the seventh output tapered waveguide 34 having the same structure and size. an output tapered waveguide 34 and a tenth output tapered waveguide 37, a ninth S-bent waveguide 39, a tenth S-bent waveguide 41, an eleventh S-bent waveguide 42 and a twelfth S-bent waveguide 44 having the same structure and size, a fifth straight waveguide 40 and a sixth straight waveguide 43 having the same structure and size, a first output straight waveguide 45, a second output straight waveguide 46, a third output straight waveguide 47, a fourth output straight waveguide 48, a fifth output straight waveguide 49 and a sixth output straight waveguide 50 having the same structure and size;

[0009] The first multimode interference waveguide 10 has three input ends and three output ends, the first input tapered waveguide 7, the second input tapered waveguide 8 and the third input tapered waveguide 9 are respectively used as the three input ends of the first multimode interference waveguide 10, and the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are respectively used as the three output ends of the first multimode interference waveguide 10; the second multimode interference waveguide 20 has one input end and two output ends, the fourth input tapered waveguide 19 is used as one input end of the second multimode interference waveguide 20, and the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 are respectively used as the two output ends of the second multimode interference waveguide 20; the third multimode interference waveguide 31 and the fourth multimode interference waveguide The fifth input tapered waveguide 27 and the sixth input tapered waveguide 28 are respectively used as the two input ends of the third multimode interference waveguide 31, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 are respectively used as the two input ends of the fourth multimode interference waveguide 32, the sixth output tapered waveguide 33, the seventh output tapered waveguide 34 and the eighth output tapered waveguide 35 are respectively used as the three output ends of the third multimode interference waveguide 31, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 are respectively used as the three output ends of the fourth multimode interference waveguide 32; the first input straight waveguide 1, the first S-bend waveguide 4 and the first input tapered waveguide 7 are connected in sequence, and the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 are respectively used as the two input ends of the fourth multimode interference waveguide 32, the sixth output tapered waveguide 33, the seventh output tapered waveguide 34 and the eighth output tapered waveguide 35 are respectively used as the three output ends of the third multimode interference waveguide 31, and the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 are respectively used as the three output ends of the fourth multimode interference waveguide 32. The second input straight waveguide 2, the first straight waveguide 5 and the second input tapered waveguide 8 are connected in sequence, the third input straight waveguide 3, the second S-bent waveguide 6 and the third input tapered waveguide 9 are connected in sequence; the first output tapered waveguide 11, the third S-bent waveguide 14, the third straight waveguide 17, the fifth S-bent waveguide 23, and the fifth input tapered waveguide 27 are connected in sequence, the second output tapered waveguide 12, the second straight waveguide 15 and the fourth input tapered waveguide 19 are connected in sequence, the fourth output tapered waveguide 21, the sixth S-bent waveguide 24 and the sixth input tapered waveguide 28 are connected in sequence, the fifth output tapered waveguide 22, the seventh S-bent waveguide 25 and the seventh input tapered waveguide 29 are connected in sequence, the third output tapered waveguide 13, the fourth S-bent waveguide 16, The fourth straight waveguide 18, the eighth S-bent waveguide 26 and the eighth input tapered waveguide 30 are connected in sequence, the sixth output tapered waveguide 33, the ninth S-bent waveguide 39 and the first output straight waveguide 45 are connected in sequence, the seventh output tapered waveguide 34, the fifth straight waveguide 40 and the second output straight waveguide 46 are connected in sequence, the eighth output tapered waveguide 35, the tenth S-bent waveguide 41 and the third output straight waveguide 47 are connected in sequence, the ninth output tapered waveguide 36, the eleventh S-bent waveguide 42 and the fourth output straight waveguide 48 are connected in sequence, the tenth output tapered waveguide 37, the sixth straight waveguide 43 and the fifth output straight waveguide 49 are connected in sequence, the eleventh output tapered waveguide 38, the twelfth S-bent waveguide 44 and the sixth output straight waveguide 50 are connected in sequence;

[0010] The first input straight waveguide 1, the second input straight waveguide 2, the third input straight waveguide 3, the first S-bend waveguide 4, the first straight waveguide 5, the second S-bend waveguide 6, the third S-bend waveguide 14, the second straight waveguide 15, the fourth S-bend waveguide 16, the third straight waveguide 17, the fourth straight waveguide 18, the fifth S-bend waveguide 23, the eighth S-bend waveguide 26, the sixth S-bend waveguide 24, the seventh S-bend waveguide 25, the ninth S-bend waveguide 39, the tenth S-bend waveguide 41, the eleventh S-bend waveguide 42, the twelfth S-bend waveguide 44, the fifth straight waveguide 40, the sixth straight waveguide 43, the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 have the same width W1=4-6 μm; the first input tapered waveguide 7, the second input tapered waveguide 8 and the third input tapered waveguide 9 have the same width at the input end, which is W1=4-6 μm; the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 have the same width at the output end, which is W1=4-6 μm; the fourth input tapered waveguide 19 has a width at the input end, which is W1=4-6 μm; the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 have the same width at the output end, which is W1=4-6 μm; the fifth input tapered waveguide 27, the sixth input tapered waveguide 28, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 have the same width at the input end, which is W1=4-6 μm; the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 have the same width at the output end, which is W1=4-6 μm;

[0011] The lengths of the first input straight waveguide 1, the second input straight waveguide 2, and the third input straight waveguide 3 are the same, i.e., L1=500-3000 μm; the projection lengths of the first S-bend waveguide 4 and the second S-bend waveguide 6 along the first straight waveguide 5 are the same as the length of the first straight waveguide 5, i.e., L2=800-2500 μm; the lengths of the first input tapered waveguide 7, the second input tapered waveguide 8, and the third input tapered waveguide 9 are the same, i.e., L3=50-200 μm; the widths of the first input tapered waveguide 7, the second input tapered waveguide 8, and the third input tapered waveguide 9 at the connection points with the first multimode interference waveguide 10 are the same, i.e., W2=5-7 μm, and W2>W1; the first multimode The width of the interference waveguide 10 is W3=20-30 μm, and the length is L4=2500-3000 μm; the width of the first multimode interference waveguide 10 at the connection with the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 is the same as W4=5-7 μm, and W4=W2>W1; the length of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 is the same as L5=50-200 μm; the length L6 of the second straight waveguide 15 is 800-2000 μm; the projection length of the third S-bend waveguide 14 and the fourth S-bend waveguide 16 along the second straight waveguide 15 is the same as L 10 = 2000 ~ 3000μm; the length of the third straight waveguide 17 and the fourth straight waveguide 18 is the same as L 11 =50~200μm; the length L7 of the fourth input tapered waveguide 19 is L7=200~500μm; the width W5 of the connection between the input tapered waveguide 19 and the second multimode interference waveguide 20 is W5=8~10μm; the length L8 of the second multimode interference waveguide 20 is L8=400~500μm, and the width W6=20~30μm; the length of the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 is the same, which is L9=60~200μm; the width of the connection between the second multimode interference waveguide 20 and the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 is the same, which is W7=6~15μm; the projection length of the sixth S-bend waveguide 24 and the seventh S-bend waveguide 25 along the extension line of the second direct waveguide 15 is the same, which is L 14 = 2000 ~ 2500μm; the fifth S-bend waveguide 23 and the ninth S-bend waveguide 26 have the same projection length along the extension line of the second direct waveguide 15 as L 12 = 1500 ~ 2000μm; the length of the fifth input tapered waveguide 27, the sixth input tapered waveguide 28, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 are the same as L 13=50-100 μm, the width of the connection between the fifth input tapered waveguide 27, the sixth input tapered waveguide 28 and the third multimode interference waveguide 31 and the width of the connection between the seventh input tapered waveguide 29, the eighth input tapered waveguide 30 and the fourth multimode interference waveguide 32 are the same, which is W8=5-10 μm; the length of the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 are the same, which is L 15 =1500~2000μm, the same width is W9=25~30μm; the width of the third multimode interference waveguide 31 and the sixth output tapered waveguide 33, the eighth output tapered waveguide 35 is connected, and the width of the fourth multimode interference waveguide 32 and the ninth output tapered waveguide 36, the eleventh output tapered waveguide 38 is connected is W 10 =5-15 μm; the width W of the connection between the third multimode interference waveguide 31 and the seventh output tapered waveguide 34 11 =5-15 μm; the width W of the connection between the fourth multimode interference waveguide 32 and the tenth output tapered waveguide 37 11 =5~15μm; W 11 <W 10 The lengths of the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 are the same, which is L. 16 = 50 ~ 100μm; the ninth S curved waveguide 39, the tenth S curved waveguide 41, the eleventh S curved waveguide 42, the twelfth S curved waveguide 44 along the fifth straight waveguide 40, the sixth straight waveguide 43 has the same length as the fifth straight waveguide 40, the sixth straight waveguide 43 is L 17 = 1500 ~ 2000μm; the lengths of the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 are the same as L 18 =500~2000μm.

[0012] As attached Figure 2 As shown, the multi-port input optical power distributor is composed of a silicon wafer substrate 51, a polymer lower cladding 52 prepared on the silicon wafer substrate 51, a polymer optical waveguide core layer 53 of a strip structure prepared on the polymer lower cladding 52, and a polymer upper cladding 54 prepared on the polymer optical waveguide core layer 53 and the polymer lower cladding 52 from bottom to top; the polymer optical waveguide core layer 53 is embedded in the polymer upper cladding 54. At this time, the polymer optical waveguide core layer 53 includes a third S-bend waveguide 14, a second straight waveguide 15 and a fourth S-bend waveguide 16. Three parts of the structure.

[0013] When the signal light is input from the first input straight waveguide 1 or the third input straight waveguide 3, it passes through the first S-bent waveguide 4 or the second S-bent waveguide 6 and enters the first input tapered waveguide 7 or the third input tapered waveguide 9 respectively, and then enters the first multimode interference waveguide 10 to excite multiple modes with the same frequency. Coupling and superposition occur between the modes, resulting in changes in the phase of the light field and mutual interference. According to the self-imaging principle of MMI, the mutually interfering light is evenly divided into two parts and enters the first output tapered waveguide 11 and the third output tapered waveguide 13, and then enters the third straight waveguide 17 and the fourth straight waveguide 18 through the third S-bent waveguide 14 and the fourth S-bent waveguide 16 for output; and then passes through the fifth S-bent waveguide 23 and the eighth S-bent waveguide 26 and enters the fifth input tapered waveguide 27 and the eighth S-bent waveguide 28 respectively. The eighth input tapered waveguide 30 enters the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 respectively. After mutual interference, the two parts of light (with the same phase difference) are evenly divided into three parts and enter the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35 and the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 respectively, and then pass through the ninth S-bent waveguide 39, the fifth straight waveguide 40, the tenth S-bent waveguide 41, the eleventh S-bent waveguide 42, the sixth straight waveguide 43, and the twelfth S-bent waveguide 44 to enter the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 for output.

[0014] When light is input from the second input straight waveguide 2, it passes through the first straight waveguide 5 into the second tapered waveguide 8, and then passes through the first multimode interference waveguide 10 into the second output tapered waveguide 12, and passes through the second straight waveguide 15 and the fourth input tapered waveguide 19 into the second multimode interference waveguide 20 to excite multiple modes with the same frequency. Coupling and superposition occur between the modes, causing the phase of the light field to change and thus interfere with each other. According to the self-imaging principle of MMI, the mutually interfering light is divided into two parts and enters the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22. The light then passes through the sixth S-bend waveguide 24 and the seventh S-bend waveguide 25, respectively, and enters the sixth input tapered waveguide 28 and the seventh input tapered waveguide 29, and then passes through the third multimode interference waveguide 19, respectively. After the interference waveguide 31 and the fourth multimode interference waveguide 32 interfere with each other, the two lights (with the same phase difference) are evenly divided into three lights, which respectively enter the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38, and then pass through the ninth S-bent waveguide 39, the fifth straight waveguide 40, the tenth S-bent waveguide 41, the eleventh S-bent waveguide 42, the sixth straight waveguide 43, and the twelfth S-bent waveguide 44 to enter the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 for output.

[0015] The thickness of the silicon wafer substrate 51 is 0.5-1 mm, the thickness of the polymer lower cladding layer 52 is 1-8 μm, the thickness of the polymer optical waveguide core layer 53 is 1-10 μm, and the thickness of the polymer upper cladding layer 54 on the polymer optical waveguide core layer is 1-8 μm.

[0016] The preparation method of the MMI structure polymer power divider according to the present invention is shown in the attached Figure 3 , the specific steps are as follows:

[0017] A: Cleaning of silicon wafer substrate

[0018] First, a 0.5-1 mm thick silicon wafer substrate 51 is repeatedly wiped with a cotton ball soaked in an acetone reagent, and then the silicon wafer substrate is repeatedly wiped with a cotton ball soaked in an ethanol reagent. After wiping it clean, it is repeatedly rinsed with deionized water. Finally, the silicon wafer substrate 51 is blown dry with nitrogen, and then placed in a clean culture dish and sealed for storage;

[0019] B: Preparation of the lower cladding of polymer optical waveguide

[0020] The polymer lower cladding material (the polymer lower cladding material is a series of organic polymer materials with good transparency including polycarbonate (PC), polyimide (PI), polymethyl methacrylate (PMMA), polyethylene (PE), polyester (PET), polystyrene (PS), EpoClad, etc.) is spin-coated on one side surface of the cleaned silicon wafer substrate 51 by spin coating process, the spin coating speed is 1000-5000 rpm, and after spin coating, it is baked at 100°C-150°C for 3-60 minutes (special materials such as EpoClad need to be exposed as a whole for 5-30 seconds after baking, and then baked at 120°C-150°C for 3-60 minutes), and the thickness of the obtained polymer lower cladding 52 is 1-8 μm;

[0021] C: Preparation of polymer optical waveguide core layer

[0022] The polymer optical waveguide core layer material (the polymer optical waveguide core layer is a series of wet-etchable ultraviolet negative photoresist materials including EpoCore, SU-8 2002, and SU-8 2005, and the refractive index of the polymer optical waveguide core layer material is higher than the refractive index of the polymer upper and lower cladding layers) is spin-coated on the polymer lower cladding layer 52 to form a polymer optical waveguide core layer film 53', the spin coating speed is 1000-5000 rpm, and the thickness of the prepared polymer optical waveguide core layer film 53' is 1-10 μm; the prepared polymer optical waveguide core layer film 53' is pre-baked, that is, baked at 50° C. to 180° C. for 3-30 minutes, and naturally cooled to room temperature after baking; the polymer optical waveguide core layer film 53' is subjected to plate-to-plate photolithography, the ultraviolet light wavelength emitted by the photolithography machine is 350-400 nm, and the waveguide mask is complementary to the structure of the polymer optical waveguide core layer 53 of the power divider to be prepared (such as Figure 1 As shown in the figure, when the photolithography plate is in close contact with the silicon wafer substrate 51, exposure is performed for 4 to 40 seconds, so that the polymer optical waveguide core layer film within the structure of the polymer optical waveguide core layer 53 to be prepared is exposed to ultraviolet light; the silicon wafer substrate 51 after photolithography is taken out from the photolithography machine for intermediate baking, and is baked at 50°C to 180°C for 5 to 30 minutes. After baking, it is naturally cooled to room temperature; the polymer optical waveguide core layer film 53' is developed, that is, firstly wet-etched in a developer corresponding to the polymer optical waveguide core layer material The non-exposed non-polymer optical waveguide core structure is removed by etching for 10 to 60 seconds, leaving only the polymer optical waveguide core structure corresponding to the mask, and then the developer and the polymer optical waveguide core material remaining on the surface of the silicon wafer substrate 51 are washed away with an isopropyl alcohol solution, and then the isopropyl alcohol remaining on the surface is rinsed clean with deionized water and blown dry with nitrogen; finally, the film is baked at a temperature of 120° C. to 150° C. for 30 to 60 minutes to post-bake the film, thereby completing the preparation of the polymer optical waveguide core layer 53 with a strip structure;

[0023] D: Preparation of the upper cladding layer of polymer optical waveguide

[0024] The polymer upper cladding material is spin-coated on the polymer optical waveguide core layer 53 and the polymer lower cladding 52 by a spin coating process, and the spin coating speed is 1000 to 5000 rpm. After the spin coating is completed, it is baked at 120° C. to 150° C. for 3 to 60 minutes. The thickness of the polymer upper cladding 54 on the polymer optical waveguide core layer is 1 to 8 μm, thereby completing the preparation of the multi-port input power divider described in the present invention.

[0025] Compared with the existing device structure and preparation technology, the beneficial effects of the present invention are:

[0026] The waveguide power divider of the present invention combines the characteristics of large process tolerance and small size of the MMI optical waveguide structure, and also utilizes the advantages of a wide variety of organic polymer materials to achieve the purpose of distributing the same power to multiple different port inputs; in addition, the process of preparing the device using polymer materials is relatively simple, requiring only conventional processes such as spin coating and photolithography, and does not require more difficult processes, and has low production cost, high efficiency, and can be mass-produced, so it is a power divider that can be applied in practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : A schematic diagram of the structure of the multi-channel optical power distributor based on the MMI structure of the present invention;

[0028] Figure 2 : Figure 1 Schematic diagram of the cross section at AA';

[0029] Figure 3 : A flow chart of the preparation process of the optical power distributor with multi-port input according to the present invention;

[0030] Figure 4 Middle (a): The left figure is a simulation diagram of the light field transmission when the multi-port input optical power divider is input from the first input straight waveguide 1, and the right figure is a diagram of the transmission efficiency of the device corresponding to different lengths;

[0031] Figure 4 Middle (b): The left figure is a simulation diagram of the light field transmission when the multi-port input optical power divider is input from the second input straight waveguide 2, and the right figure is a diagram of the transmission efficiency of the device corresponding to different lengths;

[0032] Figure 4 Middle (c): The left figure is a simulation diagram of the light field transmission when the multi-port input optical power divider is input from the third input straight waveguide 3, and the right figure is a diagram of the transmission efficiency of the device corresponding to different lengths;

[0033] Figure 5(a): The relationship between the normalized output power and the wavelength of the multi-port input optical power distributor when the input is from the first input straight waveguide 1;

[0034] Figure 5 Middle (b): The relationship curve of the normalized output power of the multi-port input optical power distributor with the wavelength when the input is from the second input straight waveguide 2;

[0035] Figure 5 Middle (c): The relationship curve of the normalized output power of the multi-port input optical power distributor as a function of wavelength when the input is from the third input straight waveguide 3. DETAILED DESCRIPTION

[0036] Example 1

[0037] like Figure 1 As shown, the multi-port input optical power divider comprises a first input straight waveguide 1, a second input straight waveguide 2, a third input straight waveguide 3, a first S-bent waveguide 4 and a second S-bent waveguide 6, a first straight waveguide 5, a first input tapered waveguide 7, a second input tapered waveguide 8, a third input tapered waveguide 9, a first multimode interference waveguide 10, a first output tapered waveguide 11, a second output tapered waveguide 12, a third output tapered waveguide 13, a third S-bent waveguide 14, a fourth S-bent waveguide 16, a second straight waveguide 15, a third straight waveguide 17, a fourth straight waveguide 18, a fourth input tapered waveguide 19, a second multimode interference waveguide 20, a fourth output tapered waveguide 21, a fifth output tapered waveguide 22, a fifth S-bent waveguide 23, an eighth S-bent waveguide 26, a sixth S-bent waveguide 24, a seventh The multimode interference waveguide of the present invention is an S-curved waveguide 25, a fifth input tapered waveguide 27, a sixth input tapered waveguide 28, a seventh input tapered waveguide 29, an eighth input tapered waveguide 30, a third multimode interference waveguide 31, a fourth multimode interference waveguide 32, a sixth output tapered waveguide 33, an eighth output tapered waveguide 35, a ninth output tapered waveguide 36, an eleventh output tapered waveguide 38, a seventh output tapered waveguide 34, a tenth output tapered waveguide 37, a ninth S-curved waveguide 39, a tenth S-curved waveguide 41, an eleventh S-curved waveguide 42, a twelfth S-curved waveguide 44, a fifth straight waveguide 40, a sixth straight waveguide 43, a first output straight waveguide 45, a second output straight waveguide 46, a third output straight waveguide 47, a fourth output straight waveguide 48, a fifth output straight waveguide 49 and a sixth output straight waveguide 50.

[0038] The first multimode interference waveguide 10 has three input ends and three output ends, the first input tapered waveguide 7, the second input tapered waveguide 8 and the third input tapered waveguide 9 are respectively used as the three input ends of the first multimode interference waveguide 10, and the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are respectively used as the three output ends of the first multimode interference waveguide 10; the second multimode interference waveguide 20 has one input end and two output ends, the fourth input tapered waveguide 19 is used as the input end of the second multimode interference waveguide 20, and the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 are respectively used as the two output ends of the second multimode interference waveguide 20; the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 are respectively used as the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 The first multimode interference waveguide 31 has two input ends and three output ends respectively; the fifth input tapered waveguide 27 and the sixth input tapered waveguide 28 are respectively used as the two input ends of the third multimode interference waveguide 31, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 are respectively used as the two input ends of the fourth multimode interference waveguide 32, the sixth output tapered waveguide 33, the seventh output tapered waveguide 34 and the eighth output tapered waveguide 35 are respectively used as the three output ends of the third multimode interference waveguide 31, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 are respectively used as the three output ends of the fourth multimode interference waveguide 32; the first input straight waveguide 1, the first S-bend waveguide 4 and the first input tapered waveguide 7 are connected in sequence, and the second The input straight waveguide 2, the first straight waveguide 5 and the second input tapered waveguide 8 are connected in sequence, the third input straight waveguide 3, the second S-bent waveguide 6 and the third input tapered waveguide 9 are connected in sequence; the first output tapered waveguide 11, the third S-bent waveguide 14, the third straight waveguide 17, the fifth S-bent waveguide 23, and the fifth input tapered waveguide 27 are connected in sequence, the second output tapered waveguide 12, the second straight waveguide 15 and the fourth input tapered waveguide 19 are connected in sequence, the fourth output tapered waveguide 21, the sixth S-bent waveguide 24 and the sixth input tapered waveguide 28 are connected in sequence, the fifth output tapered waveguide 22, the seventh S-bent waveguide 25 and the seventh input tapered waveguide 29 are connected in sequence, the third output tapered waveguide 13, the fourth S-bent waveguide 16, The fourth straight waveguide 18, the eighth S-bent waveguide 26 and the eighth input tapered waveguide 30 are connected in sequence, the sixth output tapered waveguide 33, the ninth S-bent waveguide 39 and the first output straight waveguide 45 are connected in sequence, the seventh output tapered waveguide 34, the fifth straight waveguide 40 and the second output straight waveguide 46 are connected in sequence, the eighth output tapered waveguide 35, the tenth S-bent waveguide 41 and the third output straight waveguide 47 are connected in sequence, the ninth output tapered waveguide 36, the eleventh S-bent waveguide 42 and the fourth output straight waveguide 48 are connected in sequence, the tenth output tapered waveguide 37, the sixth straight waveguide 43 and the fifth output straight waveguide 49 are connected in sequence, and the eleventh output tapered waveguide 38, the twelfth S-bent waveguide 44 and the sixth output straight waveguide 50 are connected in sequence.

[0039] The first input straight waveguide 1, the second input straight waveguide 2, the third input straight waveguide 3, the first S-bent waveguide 4, the first straight waveguide 5, the second S-bent waveguide 6, the third S-bent waveguide 14, the second straight waveguide 15, the fourth S-bent waveguide 16, the third straight waveguide 17, the fourth straight waveguide 18, the fifth S-bent waveguide 23, the sixth S-bent waveguide 24, the seventh S-bent waveguide 25, the eighth S-bent waveguide 26, the ninth S-bent waveguide 39, the tenth S-bent waveguide 41, the eleventh S-bent waveguide 42, the twelfth S-bent waveguide 44, the fifth straight waveguide 40, the sixth straight waveguide 43, the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 have the same width W1=4; the first input tapered waveguide 7, the second input tapered waveguide the width of the first input tapered waveguide 8 and the third input tapered waveguide 9 at the input ends is the same, which is W1=4μm; the width of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 at the output ends is the same, which is W1=4μm; the width of the fourth input tapered waveguide 19 at the input end is W1=4μm; the width of the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 at the output ends is the same, which is W1=4μm; the width of the fifth input tapered waveguide 27, the sixth input tapered waveguide 28, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 at the input ends is the same, which is W1=4μm; the width of the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 at the output ends is the same, which is W1=4μm;

[0040] The lengths of the first input straight waveguide 1, the second input straight waveguide 2, and the third input straight waveguide 3 are the same, which is L1=500μm; the projection lengths of the first S-bend waveguide 4 and the second S-bend waveguide 6 along the first straight waveguide 5 are the same as the length of the first straight waveguide 5, which is L2=1500μm; the lengths of the first input tapered waveguide 7, the second input tapered waveguide 8, and the third input tapered waveguide 9 are the same, which is L3=60μm; the widths of the first input tapered waveguide 7, the second input tapered waveguide 8, and the third input tapered waveguide 9 at the connection with the first multimode interference waveguide 10 are the same, which is W2 =6μm; the width of the first multimode interference waveguide 10 is W3=25μm, and the length is L4=2580μm; the width of the first multimode interference waveguide 10 at the connection with the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 is the same as W4=6μm; the length of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 is the same as L5=50μm; the length of the second straight waveguide 15 is L6 is 800μm; the length of the third S-bend waveguide 14 and the fourth S-bend waveguide 16 is the same as L 10= 2000 μm; the lengths of the third straight waveguide 17 and the fourth straight waveguide 18 are the same as L 11 =50μm; the length of the fourth input tapered waveguide 19 is L7=200μm; the width of the connection between the input tapered waveguide 19 and the second multimode interference waveguide 20 is W5=8μm; the length of the second multimode interference waveguide 20 is L8=406.66μm, and the width is W6=20μm; the length of the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 is the same, which is L9=60μm; the width of the connection between the second multimode interference waveguide 20 and the fourth output tapered waveguide 21 and the fifth output tapered waveguide 22 is the same, which is W7=6μm; the projection length of the sixth S-bend waveguide 24 and the seventh S-bend waveguide 25 along the extension line of the second direct waveguide 15 is the same, which is L 14 = 2383.34 μm; the projection length of the fifth S-bend waveguide 23 and the ninth S-bend waveguide 26 along the extension line of the second direct waveguide 15 is the same as L 12 =1800μm; the lengths of the fifth input tapered waveguide 27, the sixth input tapered waveguide 28, the seventh input tapered waveguide 29 and the eighth input tapered waveguide 30 are the same as L 13 =60 μm, the width of the connection between the fifth input tapered waveguide 27, the sixth input tapered waveguide 28 and the third multimode interference waveguide 31 and the width of the connection between the seventh input tapered waveguide 29, the eighth input tapered waveguide 30 and the fourth multimode interference waveguide 32 are the same, which is W8=6.6 μm; the length of the third multimode interference waveguide 31 and the fourth multimode interference waveguide 32 are the same, which is L 15 =1729 μm, the same width is W9=25 μm; the width of the third multimode interference waveguide 31 and the sixth output tapered waveguide 33, the eighth output tapered waveguide 35 is connected, and the width of the fourth multimode interference waveguide 32 and the ninth output tapered waveguide 36, the eleventh output tapered waveguide 38 is connected is W 10 =6μm; the width W of the connection between the third multimode interference waveguide 31 and the seventh output tapered waveguide 34 11 =5.2μm; the width W of the fourth multimode interference waveguide 32 and the tenth output tapered waveguide 37 at the connection 11 =5.2μm; the lengths of the sixth output tapered waveguide 33, the seventh output tapered waveguide 34, the eighth output tapered waveguide 35, the ninth output tapered waveguide 36, the tenth output tapered waveguide 37 and the eleventh output tapered waveguide 38 are the same as L 16 =97.47 μm; the projection lengths of the ninth S-bend waveguide 39, the tenth S-bend waveguide 41, the eleventh S-bend waveguide 42, and the twelfth S-bend waveguide 44 along the fifth straight waveguide 40 and the sixth straight waveguide 43 are the same as the lengths of the fifth straight waveguide 40 and the sixth straight waveguide 43, which is L 17= 2000 μm; the lengths of the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49, and the sixth output straight waveguide 50 are the same as L 18 =500μm.

[0041] As attached Figure 2 As shown, from bottom to top, it is composed of a silicon wafer substrate 51, a polymer lower cladding layer 52 prepared on the silicon wafer substrate 51, a polymer optical waveguide core layer 53 of a strip structure prepared on the polymer lower cladding layer 52, and a polymer upper cladding layer 54 prepared on the polymer optical waveguide core layer 53. The thickness of the silicon wafer substrate 51 is 1 mm, the thickness of the polymer lower cladding layer 52 is 5 μm, the thickness of the polymer optical waveguide core layer 53 is 5 μm, and the thickness of the polymer upper cladding layer 54 is 5 μm (the thickness of the polymer upper cladding layer above the polymer optical waveguide core layer).

[0042] Figure 4 (a): A simulation diagram of light field transmission when the multi-port input optical power distributor is input from the first input straight waveguide 1. During the simulation process, we selected the materials and waveguide dimensions selected in Example 1. It can be clearly seen from the simulation diagram that when the input is a fundamental mode at a wavelength of 850nm, the outputs from the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 are fundamental modes with the same power;

[0043] Figure 4 (b): A simulation diagram of light field transmission when the multi-port input optical power distributor is input from the first input straight waveguide 2. During the simulation process, we selected the materials and waveguide dimensions selected in Example 1. It can be clearly seen from the simulation diagram that when the input is a fundamental mode at a wavelength of 850nm, the outputs from the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 are fundamental modes with the same power;

[0044] Figure 4 (c): Simulation diagram of light field transmission when the multi-port input optical power distributor inputs the light from the third input straight waveguide 3. During the simulation, we selected the materials and waveguide dimensions used in Example 1. It can be clearly seen from the simulation diagram that when the input is the fundamental mode at a wavelength of 850nm, the outputs from the first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 are the fundamental modes with the same power.

[0045] like Figure 5(a) is a curve showing the relationship between the normalized output power of the multi-port input optical power distributor and the wavelength when the input is from the input waveguide 1. We selected the materials and waveguide dimensions used in Example 1. It can be seen that in the 800-900nm band, the output power fluctuates less with the wavelength. The first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 output the same fundamental mode with the same power, and the device is not sensitive to the wavelength.

[0046] like Figure 5 (b) is a curve showing the relationship between the normalized output power of the multi-port input optical power distributor and the wavelength when the input is from the second input straight waveguide 2. We selected the materials and waveguide dimensions used in Example 1. It can be seen that in the 800-900nm band, the output power fluctuates less with the wavelength. The first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 output the same fundamental mode with the same power, and the device is not sensitive to wavelength.

[0047] like Figure 5 (c) is a curve showing the relationship between the normalized output power of the multi-port input optical power distributor and the wavelength when the input is from the third input straight waveguide 3. We selected the materials and waveguide dimensions used in Example 1. It can be seen that in the 800-900nm band, the output power fluctuates less with the wavelength. The first output straight waveguide 45, the second output straight waveguide 46, the third output straight waveguide 47, the fourth output straight waveguide 48, the fifth output straight waveguide 49 and the sixth output straight waveguide 50 output the same fundamental mode with the same power, and the device is not sensitive to wavelength.

[0048] Example 2

[0049] like Figure 3 As shown, 51 in the figure is a silicon wafer substrate, 52 is a polymer lower cladding layer prepared by a spin coating process, 53 is a polymer optical waveguide core layer prepared by a spin coating, photolithography, and wet etching process, and 54 is a polymer upper cladding layer prepared by a spin coating process. The specific steps are as follows:

[0050] (1) Cleaning of silicon wafer substrate: Wipe the silicon wafer substrate 51 vigorously with a cotton ball soaked in acetone for three times, then wipe the silicon wafer substrate 51 vigorously with a cotton ball soaked in ethanol for three times, rinse it with deionized water after wiping it clean, finally blow dry the silicon wafer with nitrogen, and then put it in a clean culture dish and seal it for storage;

[0051] (2) Preparation of polymer optical waveguide lower cladding: The EpoClad polymer lower cladding was spin-coated on a cleaned silicon wafer substrate by a spin coating process at a speed of 3000 rpm. After the spin coating was completed, it was baked at 120° C. for 5 minutes, the whole was exposed for 12 seconds, and then baked again at 130° C. for 30 minutes. The thickness of the obtained polymer lower cladding 52 was 5 μm.

[0052] (3) The polymer optical waveguide core layer 53 of the device including the input / output region and the multi-mode interference region is prepared by spin coating, photolithography and wet etching processes: the EpoCore polymer optical waveguide core layer is spin coated on the polymer lower cladding layer by spin coating to form a polymer optical waveguide core layer film 53', the spin coating speed is 3000 rpm, and the thickness of the prepared polymer optical waveguide core layer film 53' is 5 μm; the prepared polymer optical waveguide core layer film 53' is pre-baked by a step-by-step heating method, first baking at 50°C for 10 minutes, then baking at 95°C for 15 minutes, and then cooling after baking; the prepared polymer optical waveguide core layer film 53' is subjected to plate-to-plate photolithography, the ultraviolet light wavelength emitted by the photolithography machine is 365 nm, and the waveguide mask is a structure complementary to the polymer optical waveguide core layer 53 of the mode power divider to be prepared (such as Figure 1 As shown), when the photomask is in close contact with the silicon wafer, photolithography is performed, and the exposure time is 3.5 seconds, so that the polymer optical waveguide core layer film of the device input / output area, the multi-mode interference area, and the tapered waveguide area connecting the multi-mode interference area and the input / output area to be prepared is exposed to ultraviolet light; the silicon wafer after photolithography is taken out of the photolithography machine for intermediate baking, first baked at 50°C for 10 minutes, and then baked at 85°C for 15 minutes. After the baking is completed, the temperature is lowered and the next step is performed after it drops to room temperature; the polymer optical waveguide core layer film 5 3' is developed, firstly wet-etched in a developer for 60 seconds to remove the unexposed non-polymer optical waveguide core layer structure, leaving only the polymer optical waveguide core layer film corresponding to the mask, and then the developer and the polymer optical waveguide core layer film remaining on the surface of the silicon wafer are washed away with an isopropyl alcohol solution, and then the isopropyl alcohol remaining on the surface is rinsed clean with deionized water and blown dry with nitrogen; finally, the film is post-baked at 130° C. for 40 minutes, thereby completing the preparation of the polymer optical waveguide core layer 53 with a strip structure;

[0053] (4) Preparation of polymer optical waveguide upper cladding: The EpoClad polymer upper cladding was spin-coated on the silicon wafer on which the polymer optical waveguide core layer 53 was prepared by spin coating, the spin coating speed was 3000 rpm, and after the spin coating was completed, it was baked at 120°C for 5 minutes, the whole was exposed for 12 seconds, and then baked again for 3 minutes. The thickness of the polymer upper cladding above the polymer optical waveguide core layer was 5 μm. In this way, the preparation of the MMI structure polymer multi-port input optical power distributor at 850 nm was completed.

[0054] It should be pointed out that the specific implementation methods are only representative examples of the present invention. Obviously, the technical solutions of the present invention include but are not limited to the above embodiments, and there may be more forms, such as each power divider can be cascaded as a unit structure to achieve further expansion and application, and the material of the design is not limited to this, and optical waveguide materials such as silicon, silicon nitride, and lithium niobate can also be used. Those skilled in the art who are clearly disclosed in the present invention or obtained without objection based on the written description of the document belong to the scope of protection of the present invention.

Claims

1. A multi-channel optical power divider based on MMI structure, characterized in that: The polymer optical waveguide core layer (53) of the strip structure is composed of a silicon wafer substrate (51), a polymer lower cladding layer (52), a polymer optical waveguide core layer (53) of a strip structure, and a polymer upper cladding layer (54) from bottom to top. The refractive index of the polymer optical waveguide core layer (53) is higher than the refractive index of the polymer lower cladding layer (52) and the polymer upper cladding layer (54). The polymer optical waveguide core layer (53) of the strip structure is coated in the polymer upper cladding layer (54). The polymer optical waveguide core layer (53) of the strip structure is based on the MMI structure. From left to right along the propagation direction of light, it is composed of a first input straight waveguide (1), a second input straight waveguide (2), and a third input straight waveguide (3) of the same structure and size. The invention relates to a first S-bend waveguide (4) and a second S-bend waveguide (6) having the same structure and size, a first straight waveguide (5), a first input tapered waveguide (7), a second input tapered waveguide (8) and a third input tapered waveguide (9) having the same structure and size, a first multimode interference waveguide (10), a first output tapered waveguide (11), a second output tapered waveguide (12) and a third output tapered waveguide (13) having the same structure and size, a third S-bend waveguide (14) and a fourth S-bend waveguide (16) having the same size and size, a second straight waveguide (15), a third straight waveguide (17) and a fourth straight waveguide (18) having the same structure and size, a fourth input tapered waveguide (19), a second multimode interference waveguide ( 20), a fourth output tapered waveguide (21) and a fifth output tapered waveguide (22) having the same structure and size, a fifth S-bend waveguide (23) and an eighth S-bend waveguide (26) having the same structure and size, a sixth S-bend waveguide (24) and a seventh S-bend waveguide (25) having the same structure and size, a fifth input tapered waveguide (27), a sixth input tapered waveguide (28), a seventh input tapered waveguide (29) and an eighth input tapered waveguide (30) having the same structure and size, a third multimode interference waveguide (31) and a fourth multimode interference waveguide (32) having the same structure and size, a sixth output tapered waveguide (33) and an eighth output tapered waveguide (35) having the same structure and size , a ninth output tapered waveguide (36) and an eleventh output tapered waveguide (38), a seventh output tapered waveguide (34) and a tenth output tapered waveguide (37) having the same structure and size, a ninth S-bend waveguide (39), a tenth S-bend waveguide (41), an eleventh S-bend waveguide (42) and a twelfth S-bend waveguide (44) having the same structure and size, a fifth straight waveguide (40) and a sixth straight waveguide (43) having the same structure and size, a first output straight waveguide (45), a second output straight waveguide (46), a third output straight waveguide (47), a fourth output straight waveguide (48), a fifth output straight waveguide (49) and a sixth output straight waveguide (50) having the same structure and size; The first multimode interference waveguide (10) has three input ends and three output ends, the first input tapered waveguide (7), the second input tapered waveguide (8) and the third input tapered waveguide (9) respectively serve as the three input ends of the first multimode interference waveguide (10), the first output tapered waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide (13) respectively serve as the three output ends of the first multimode interference waveguide (10); the second multimode interference waveguide (20 ) has one input end and two output ends, the fourth input tapered waveguide (19) serves as one input end of the second multimode interference waveguide (20), the fourth output tapered waveguide (21) and the fifth output tapered waveguide (22) serve as two output ends of the second multimode interference waveguide (20), respectively; the third multimode interference waveguide (31) and the fourth multimode interference waveguide (32) have two input ends and three output ends, respectively; the fifth input tapered waveguide (27) and the sixth input tapered waveguide (28) serve ... respectively; the fourth output tapered waveguide (21) and the fifth output tapered waveguide (22) serve as two output ends of the second multimode interference waveguide (20), respectively; the third multimode interference waveguide (31) and the fourth multimode interference waveguide (32) have two input ends and three output ends, respectively; the fifth input tapered waveguide (27) and the sixth input tapered waveguide (28) The waveguide (28) is used as two input ends of the third multimode interference waveguide (31), the seventh input tapered waveguide (29) and the eighth input tapered waveguide (30) are used as two input ends of the fourth multimode interference waveguide (32), the sixth output tapered waveguide (33), the seventh output tapered waveguide (34) and the eighth output tapered waveguide (35) are used as three output ends of the third multimode interference waveguide (31), and the ninth output tapered waveguide (36), the tenth output tapered waveguide (37) and the tenth output tapered waveguide (38) are used as the output ends of the fourth multimode interference waveguide (32). The first input straight waveguide (1), the first S-bend waveguide (4) and the first input tapered waveguide (7) are connected in sequence; the second input straight waveguide (2), the first straight waveguide (5) and the second input tapered waveguide (8) are connected in sequence; and the third input straight waveguide (3), the second S-bend waveguide (6) and the third input tapered waveguide (9) are connected in sequence;The first output tapered waveguide (11), the third S-bend waveguide (14), the third straight waveguide (17), the fifth S-bend waveguide (23), and the fifth input tapered waveguide (27) are connected in sequence; the second output tapered waveguide (12), the second straight waveguide (15), and the fourth input tapered waveguide (19) are connected in sequence; the fourth output tapered waveguide (21), the sixth S-bend waveguide (24), and the sixth input tapered waveguide (28) are connected in sequence; the fifth output tapered waveguide (22), the seventh S-bend waveguide (25), and the seventh input tapered waveguide (29) are connected in sequence; the third output tapered waveguide (13), the fourth S-bend waveguide (16), the fourth straight waveguide (18), the eighth S-bend waveguide (26), and the eighth input tapered waveguide (30) are connected in sequence; The sixth output tapered waveguide (33), the ninth S-bend waveguide (39), and the first output straight waveguide (45) are connected in sequence; the seventh output tapered waveguide (34), the fifth straight waveguide (40), and the second output straight waveguide (46) are connected in sequence; the eighth output tapered waveguide (35), the tenth S-bend waveguide (41), and the third output straight waveguide (47) are connected in sequence; the ninth output tapered waveguide (36), the eleventh S-bend waveguide (42), and the fourth output straight waveguide (48) are connected in sequence; the tenth output tapered waveguide (37), the sixth straight waveguide (43), and the fifth output straight waveguide (49) are connected in sequence; the eleventh output tapered waveguide (38), the twelfth S-bend waveguide (44), and the sixth output straight waveguide (50) are connected in sequence.; 2. A multi-channel optical power divider based on MMI structure as claimed in claim 1, characterized in that: a first input straight waveguide (1), a second input straight waveguide (2), a third input straight waveguide (3), a first S-bend waveguide (4), a first straight waveguide (5), a second S-bend waveguide (6), a third S-bend waveguide (14), a second straight waveguide (15), a fourth S-bend waveguide (16), a third straight waveguide (17), a fourth straight waveguide (18), a fifth S-bend waveguide (23), an eighth S-bend waveguide (26), a sixth S-bend waveguide (24), a seventh S-bend waveguide (25), a The widths of the ninth S-bend waveguide (39), the tenth S-bend waveguide (41), the eleventh S-bend waveguide (42), the twelfth S-bend waveguide (44), the fifth straight waveguide (40), the sixth straight waveguide (43), the first output straight waveguide (45), the second output straight waveguide (46), the third output straight waveguide (47), the fourth output straight waveguide (48), the fifth output straight waveguide (49), and the sixth output straight waveguide (50) are the same, that is, W1=4-6 μm; the first input tapered waveguide (7), The width of the second input tapered waveguide (8) and the third input tapered waveguide (9) at the input end is the same, which is W1=4-6 μm. The width of the first output tapered waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide (13) at the output end is the same, which is W1=4-6 μm. The width of the fourth input tapered waveguide (19) at the input end is W1=4-6 μm. The width of the fourth output tapered waveguide (21) and the fifth output tapered waveguide (22) at the output end is the same, which is W1=4-6 μm. m, the widths of the fifth input tapered waveguide (27), the sixth input tapered waveguide (28), the seventh input tapered waveguide (29) and the eighth input tapered waveguide (30) at their input ends are the same, namely, W1=4-6 μm, and the widths of the sixth output tapered waveguide (33), the seventh output tapered waveguide (34), the eighth output tapered waveguide (35), the ninth output tapered waveguide (36), the tenth output tapered waveguide (37) and the eleventh output tapered waveguide (38) at their output ends are the same, namely, W1=4-6 μm.

3. A multi-channel optical power divider based on MMI structure as claimed in claim 1, characterized in that: The lengths of the first input straight waveguide (1), the second input straight waveguide (2) and the third input straight waveguide (3) are the same, i.e., L1=500-3000 μm; the projected lengths of the first S-bend waveguide (4) and the second S-bend waveguide (6) along the first straight waveguide (5) are the same as the length of the first straight waveguide (5), i.e., L2=800-2500 μm; the lengths of the first input tapered waveguide (7), the second input tapered waveguide (8) and the third input tapered waveguide (9) are the same, i.e., L3=50-200 μm; the widths of the first input tapered waveguide (7), the second input tapered waveguide (8) and the third input tapered waveguide (9) at the connection with the first multimode interference waveguide (10) are the same, i.e., W2=5-7 μm, and W2>W1 ; The width W3 of the first multimode interference waveguide (10) is 20-30 μm, and the length L4 is 2500-3000 μm; the width of the first multimode interference waveguide (10) at the connection with the first output tapered waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide 13 is the same, which is W4=5-7 μm, and W4=W2>W1; the length of the first output tapered waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide 13 is the same, which is L5=50-200 μm; the length L6 of the second straight waveguide (15) is 800-2000 μm; the projection lengths of the third S-bend waveguide 14 and the fourth S-bend waveguide (16) along the second straight waveguide (15) are the same, which is L 10 = = 2000 ~ 3000 μm; the third straight waveguide (17) and the fourth straight waveguide (18) have the same length L 11 =50-200 μm; the length L7 of the fourth input tapered waveguide (19) is =200-500 μm; the width W5 of the connection between the input tapered waveguide (19) and the second multimode interference waveguide (20) is =8-10 μm; the length L8 of the second multimode interference waveguide (20) is =400-500 μm, and the width W6 is =20-30 μm; the lengths L9 of the fourth output tapered waveguide (21) and the fifth output tapered waveguide (22) are the same, which is L9=60-200 μm; the widths W7 of the connection between the second multimode interference waveguide (20) and the fourth output tapered waveguide (21) and the fifth output tapered waveguide (22) are the same, which is W7=6-15 μm; the projection lengths L1 of the sixth S-bend waveguide (24) and the seventh S-bend waveguide (25) along the extension line of the second direct waveguide (15) are the same, which is L2 14 = 2000 ~ 2500 μm; the projection length of the fifth S-bend waveguide (23) and the ninth S-bend waveguide (26) along the extension line of the second direct waveguide (15) is the same as L 12 =1500-2000 μm; the lengths of the fifth input tapered waveguide (27), the sixth input tapered waveguide (28), the seventh input tapered waveguide (29) and the eighth input tapered waveguide (30) are the same, which is L 13 =50-100 μm, the width of the connection between the fifth input tapered waveguide (27), the sixth input tapered waveguide (28) and the third multimode interference waveguide (31) and the width of the connection between the seventh input tapered waveguide (29), the eighth input tapered waveguide (30) and the fourth multimode interference waveguide (32) are the same, W8=5-10 μm; the length of the third multimode interference waveguide (31) and the fourth multimode interference waveguide (32) are the same, L 15 =1500-2000 μm, and the width is the same as W9=25-30 μm; the width of the connection between the third multimode interference waveguide (31) and the sixth output tapered waveguide (33) and the eighth output tapered waveguide (35) and the width of the connection between the fourth multimode interference waveguide (32) and the ninth output tapered waveguide (36) and the eleventh output tapered waveguide (38) are the same as W 10 =5-15 μm; Width W at the junction of the third multimode interference waveguide (31) and the seventh output tapered waveguide (34) 11 =5-15 μm; the width W of the connection between the fourth multimode interference waveguide (32) and the tenth output tapered waveguide (37) 11 =5~15μm; W 11 <W 10 The lengths of the sixth output tapered waveguide (33), the seventh output tapered waveguide (34), the eighth output tapered waveguide (35), the ninth output tapered waveguide (36), the tenth output tapered waveguide (37) and the eleventh output tapered waveguide (38) are the same, which is L. 16 =50-100 μm; the projection lengths of the ninth S-bend waveguide (39), the tenth S-bend waveguide (41), the eleventh S-bend waveguide (42), and the twelfth S-bend waveguide (44) along the fifth straight waveguide (40) and the sixth straight waveguide (43) are the same as the lengths of the fifth straight waveguide (40) and the sixth straight waveguide (43), which is L 17 =1500-2000 μm; the lengths of the first output straight waveguide (45), the second output straight waveguide (46), the third output straight waveguide (47), the fourth output straight waveguide (48), the fifth output straight waveguide (49), and the sixth output straight waveguide (50) are the same, which is L 18 =500~2000μm.

4. A multi-channel optical power divider based on MMI structure as claimed in claim 1, characterized in that: The thickness of the silicon wafer substrate (51) is 0.5-1 mm, the thickness of the polymer lower cladding layer (52) is 1-8 μm, the thickness of the polymer optical waveguide core layer (53) is 1-10 μm, and the thickness of the polymer upper cladding layer (54) on the polymer optical waveguide core layer is 1-8 μm.

5. The multi-channel optical power divider based on MMI structure as claimed in claim 1, characterized in that: The material of the polymer lower cladding layer (52) and the polymer upper cladding layer (54) is one of polycarbonate, polyimide, polymethyl methacrylate, polyethylene, polyester, polystyrene, and EpoClad; the material of the polymer optical waveguide core layer (53) is one of EpoCore, SU-8=2002, and SU-8=2005.

6. The method for preparing a multi-channel optical power distributor based on an MMI structure according to any one of claims 1 to 5, wherein the steps are as follows: A: Cleaning of silicon wafer substrate First, the silicon wafer substrate (51) is repeatedly wiped with a cotton ball soaked in an acetone reagent, and then the silicon wafer substrate (51) is repeatedly wiped with a cotton ball soaked in an ethanol reagent. After wiping it clean, it is repeatedly rinsed with deionized water. Finally, the silicon wafer substrate (51) is blown dry with nitrogen gas, and then placed in a clean culture dish and sealed for storage; B: Preparation of polymer optical waveguide lower cladding (52) The polymer lower cladding material is spin-coated on one side of a cleaned silicon wafer substrate (51) by a spin-coating process, the spin-coating speed is 1000-5000 rpm, and after the spin-coating is completed, it is baked at 100° C.-150° C. for 3-60 minutes; C: Preparation of polymer optical waveguide core layer (53) The polymer optical waveguide core layer material is spin-coated on the polymer lower cladding layer (52) by a spin coating process to form a polymer optical waveguide core layer film (53'), and the spin coating speed is 1000-5000 rpm; the prepared polymer optical waveguide core layer film (53') is pre-baked, that is, baked at 50°C-180°C for 3-30 minutes, and naturally cooled to room temperature after baking; the polymer optical waveguide core layer film (53') is plate-etched, the ultraviolet light wavelength emitted by the photolithography machine is 350-400nm, the waveguide mask is complementary to the structure of the polymer optical waveguide core layer (53) of the power distributor to be prepared, and exposure is performed when the photolithography plate is closely attached to the silicon wafer substrate (51), and the exposure time is 4-40 seconds, so that the polymer optical waveguide core layer film (53') within the structure of the polymer optical waveguide core layer (53) to be prepared is ') is exposed to ultraviolet light; the silicon wafer substrate (51) after photolithography is removed from the photolithography machine for intermediate baking, baking at 50°C to 180°C for 5 to 30 minutes, and cooling naturally to room temperature after baking; the polymer optical waveguide core layer film (53') is developed, that is, first wet-etching in a developer corresponding to the polymer optical waveguide core layer material for 10 to 60 seconds to remove the unexposed non-polymer optical waveguide core layer structure, leaving only the polymer optical waveguide core layer structure corresponding to the mask, and then washing the developer and the polymer optical waveguide core layer material remaining on the surface of the silicon wafer substrate (51) with an isopropanol solution, and then rinsing the isopropanol remaining on the surface with deionized water and blowing it dry with nitrogen; finally baking at a temperature of 120°C to 150°C for 30 to 60 minutes to post-bake the film, thereby completing the preparation of the polymer optical waveguide core layer (53) with a strip structure; D: Preparation of the upper cladding layer (54) of the polymer optical waveguide The polymer upper cladding material is spin-coated on the polymer optical waveguide core layer (53) and the polymer lower cladding (52) by a spin coating process, the spin coating speed is 1000 to 5000 revolutions per minute, and after the spin coating is completed, it is baked at 120° C. to 150° C. for 3 to 60 minutes, thereby completing the preparation of the multi-port input power distributor.

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