A polymer waveguide optical power divider based on MMI structure with multi-port input and multi-port output and its preparation method

Abstract

A multi-port input, multi-port output polymer waveguide optical power divider based on an MMI structure and a preparation method thereof belong to the technical field of planar optical waveguide devices and their preparation. From bottom to top, it is composed of a silicon wafer substrate, a polymer lower cladding, a polymer optical waveguide core layer, and a polymer upper cladding. The polymer optical waveguide core layer and the polymer upper cladding are located together on the polymer lower cladding. The polymer optical waveguide core layer is completely covered in the polymer upper cladding. The refractive index of the polymer optical waveguide core layer material is higher than that of the polymer upper and lower claddings. The entire polymer optical waveguide core layer is based on an MMI optical waveguide structure. The waveguide-type power divider of the present invention combines the characteristics of the MMI optical waveguide structure with large process tolerance and small size, and 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. It can be mass-produced and is a power divider that can be applied in practice.

Description

Technical Field

[0001] The present invention belongs to the technical field of planar optical waveguide devices and their preparation, and in particular relates to a polymer waveguide optical power divider based on an MMI structure with multi-port input and multi-port output and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of information technology, people have placed higher demands on the communication capacity, transmission rate, and reliability of optical communication systems. As a core component of optical communication systems and on-chip optical interconnect integrated circuits, optical power dividers evenly distribute the input optical signal power to several output ports, thereby achieving the distribution and synthesis of optical signals. They are the basic components of optical switches, optical modulators, multiplexers, and demultiplexers. Among them, optical power dividers based on planar optical waveguide structures function to split an input signal into multiple output signals to meet specific application requirements. They are not only highly compatible with optical fibers, but also have the advantages of compact structure, tunability, low insertion loss, and flexible design.

[0003] In the existing technical field, we find that currently proposed optical power dividers generally adopt single-ended input structures, such as the common 1×3, 1×6, and 1×N structures. These traditional optical power dividers have certain limitations in the design of the input ports, and have long failed to achieve fundamental breakthroughs. This situation has, to a certain extent, restricted the application of optical power dividers in more complex network environments.

[0004] However, with the continuous development of science and technology and the increasing requirements for equipment performance in actual application scenarios, in order to effectively improve the flexibility of the port network to better adapt to diverse network layouts and realize the key function of multi-port input and multi-port output, the present invention proposes a new optical power splitter with the characteristics of multi-port input and multi-port output, which brings new avenues for the development of related fields such as optical communications and is expected to solve the shortcomings of traditional optical power splitters in complex application scenarios. Summary of the Invention

[0005] In order to overcome the shortcomings of traditional optical power dividers, the purpose of the present invention is to provide a polymer waveguide 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 and organic polymer materials as the upper and lower cladding layers of the optical waveguide. The core layer of the polymer optical waveguide utilizes organic polymer materials with different refractive indices. This design leverages the diversity, flexible processing properties, and low cost of existing polymer materials. Furthermore, the fabrication process is simple, compatible with semiconductor processes, and easily integrated, making it suitable for large-scale production. Therefore, this invention has significant application value in the fields of optical communications and planar optical waveguide power dividers.

[0007] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0008] A multi-port input, multi-port output polymer waveguide optical power divider based on MMI structure, which is composed of a silicon wafer substrate 20, a polymer lower cladding 21, a polymer optical waveguide core layer 22' and a polymer upper cladding 23 from bottom to top. The polymer optical waveguide core layer 22' and the polymer upper cladding 23 are located on the polymer lower cladding 21, and the polymer optical waveguide core layer 22' is completely covered in the polymer upper cladding 23; the entire polymer optical waveguide core layer 22' is based on the MMI optical waveguide structure, as shown in the attached figure. Figure 1 As shown, 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 with the same structure and size and parallel to each other, a first S-bend waveguide 4 and a second S-bend waveguide 6 with the same structure and size, a first parallel 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 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-bend waveguide 14 and a fourth S-bend waveguide 16 with the same structure and size, a second parallel straight waveguide 15, a first output straight waveguide 17, a second output straight waveguide 18, and a third output straight waveguide 19 with the same structure and size and parallel to each other; the first input tapered waveguide 7, the second input tapered waveguide 8, and the third input tapered waveguide 9 with the same structure and size, a multimode interference waveguide 10 The guide 8 and the third input tapered waveguide 9 serve as the three input ends of the multimode interference waveguide 10 respectively, and the first output straight waveguide 17, the second output straight waveguide 18 and the third output straight waveguide 19 serve as the three output ends of the multimode interference waveguide 10 respectively; the first input straight waveguide 1, the first S-bent waveguide 4 and the first input tapered waveguide 7 are connected in sequence, the second input straight waveguide 2, the first parallel 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 and the first output straight waveguide 17 are connected in sequence, the second output tapered waveguide 12, the second parallel straight waveguide 15 and the second output straight waveguide 18 are connected in sequence, and the third output tapered waveguide 13, the fourth S-bent waveguide 16 and the third output straight waveguide 19 are connected in sequence.

[0009] The widths of 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 parallel straight waveguide 5, the second S-bend waveguide 6, the third S-bend waveguide 14, the second parallel straight waveguide 15, the fourth S-bend waveguide 16, the first output straight waveguide 17, the second output straight waveguide 18 and the third output straight waveguide 19 are equal, namely, W1=4-6 μm; the widths of the input ends of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are equal, namely, W1=4-6 μm. The widths of the output ends of the second output tapered waveguide 12 and the third output tapered waveguide 13 are equal, namely W1=4-6 μm; the lengths of the first input straight waveguide 1, the second input straight waveguide 2, and the third input straight waveguide 3 are equal, namely L1=500-3000 μm; the projected lengths of the first S-bend waveguide 4 and the second S-bend waveguide 6 along the first parallel straight waveguide 5 are equal, namely L2=800-2500 μm, and the length of the first parallel straight waveguide 5 is 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 equal. The width 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 multimode interference waveguide 10 is equal to W2=5-6μm, and W2>W1; the width W3 of the multimode interference waveguide 10 is 20-30μm, and the length L4 is 1500-2000μm; the width W4 at the connection between the multimode interference waveguide 10 and the second output tapered waveguide 12 is equal to W4=5-6μm, and the width of the multimode interference waveguide 10 at the connection with the first output tapered waveguide 11 and the third output tapered waveguide 13 is equal to W5= 5~15 μm, and W5>W4; the lengths of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are equal, namely L5=50~200 μm; the projected lengths of the third S-curved waveguide 14 and the fourth S-curved waveguide 16 along the second parallel straight waveguide 15 are equal, namely L6=800~2000 μm, and the length of the second parallel straight waveguide 15 is L6=800~2000 μm; the lengths of the first output straight waveguide 17, the second output straight waveguide 18 and the third output straight waveguide 19 are equal, namely L7=500~2000 μm.

[0010] As attached Figure 2 As shown, Figure 1Schematic diagram of a cross section at AA' in the middle; from bottom to top, it consists of a silicon wafer substrate 20, a polymer lower cladding layer 21 prepared on the silicon wafer substrate 20, a strip-shaped polymer optical waveguide core layer 22' prepared on the polymer lower cladding layer 21, and a polymer upper cladding layer 23 prepared on the polymer optical waveguide core layer 22' and the polymer lower cladding layer 21; the polymer optical waveguide core layer 22' is embedded in the polymer upper cladding layer 23; at this time, the polymer optical waveguide core layer 22' includes three parts: a first S-bend waveguide 4, a first parallel straight waveguide 5, and a second S-bend waveguide 6.

[0011] The signal light can be input from the first input straight waveguide 1, the second input straight waveguide 2 or the third input straight waveguide 3 respectively, and then pass through the first S-bend waveguide 4, the first parallel straight waveguide 5 or the second S-bend waveguide 6 to enter the first input tapered waveguide 7, the second input tapered waveguide 8 or the third input tapered waveguide 9, and then enter the multimode interference waveguide 10 to excite multiple modes. Due to the structure and material properties of the multimode waveguide, at a specific transmission distance, the signal light will be recombined into a field distribution similar to the input light field. The light is evenly divided into three paths and enters the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13, and then passes through the third S-bend waveguide 14, the second parallel straight waveguide 15 and the fourth S-bend waveguide 16 respectively, and finally output from the first output straight waveguide 17, the second output straight waveguide 18 and the third output straight waveguide 19.

[0012] The thickness of the silicon wafer substrate 20 is 0.5-1 mm, the thickness of the polymer lower cladding layer 21 is 3-15 μm, the thickness of the polymer optical waveguide core layer 22 ′ is 2-10 μm, and the thickness of the polymer upper cladding layer 23 on the polymer optical waveguide core layer 22 ′ is 3-15 μm.

[0013] The present invention relates to a method for preparing a polymer waveguide optical power divider with multi-port input and multi-port output based on an MMI structure. The manufacturing process is shown in the attached Figure 3 , the specific steps are as follows:

[0014] A: Cleaning of silicon wafer substrates

[0015] Wipe the silicon wafer substrate 20 vigorously with a cotton ball soaked in acetone, repeatedly wiping 2 to 3 times; then wipe the silicon wafer substrate 20 vigorously with a cotton ball soaked in ethanol, repeatedly wiping 2 to 3 times; after wiping clean, rinse it repeatedly with deionized water, and finally blow dry the silicon wafer with nitrogen, then place it in a clean culture dish and seal it for storage;

[0016] B: Preparation of polymer optical waveguide lower cladding

[0017] A 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 a cleaned silicon wafer substrate 20 using a spin coating process. The spin coating speed is 1000-5000 rpm. After the spin coating is completed, the substrate is baked at 100° C.-150° C. for 3-60 minutes (special materials such as EpoClad need to be baked at 110-130° C. for 1-10 minutes after baking, the entire substrate is exposed for 5-30 seconds, and then baked at 130-150° C. for 2-50 minutes). The thickness of the obtained polymer lower cladding layer 21 is 3-15 μm.

[0018] C: Preparation of polymer optical waveguide core layer

[0019] A polymer optical waveguide core layer material (the polymer optical waveguide core layer is a series of wet-etchable UV 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 21 to form a polymer optical waveguide core layer film 22. The spin coating speed is 1000 to 5000 rpm, and the thickness of the prepared polymer optical waveguide core layer film 22 is 2 to 10 μm. The prepared polymer optical waveguide core layer film 22 is pre-baked, that is, baked at 50° C. to 180° C. for 3 to 30 minutes, and then naturally cooled to room temperature after baking. The polymer optical waveguide core layer film 22 is subjected to plate-alignment photolithography. The ultraviolet light wavelength emitted by the photolithography machine is 350 to 400 nm. The waveguide mask is complementary to the structure of the polymer optical waveguide core layer 22 to be prepared (such as Figure 1 As shown), when the photomask is in close contact with the silicon wafer substrate, exposure is performed for 4 to 40 seconds, so that the polymer optical waveguide core layer film 22 within the polymer optical waveguide core layer 22' structure to be prepared is exposed to ultraviolet light; the silicon wafer substrate after photolithography is removed from the photolithography machine for intermediate baking, that is, baking at 50°C to 180°C for 5 to 30 minutes, and then naturally cooling to room temperature after baking; the polymer optical waveguide core layer 22' structure is developed, that is, first wet-etching in a developer corresponding to the polymer optical waveguide core layer material After 10 to 60 seconds, the unexposed polymer waveguide core layer film 22 is removed, leaving only the polymer waveguide core layer 22' structure corresponding to the mask. The developer and the polymer waveguide core layer material remaining on the silicon wafer surface are then washed away with an isopropyl alcohol solution. The remaining isopropyl alcohol on the surface is then rinsed clean with deionized water and blown dry with nitrogen. Finally, the film is post-baked at 120° C. to 150° C. for 30 to 60 minutes to complete the preparation of the polymer waveguide core layer 22' with a strip structure.

[0020] D: Preparation of the upper cladding layer of polymer optical waveguide

[0021] The polymer upper cladding material is spin-coated onto the waveguide core layer 22' and the polymer lower cladding layer 21 using a spin coating process at a spin coating speed of 1000 to 5000 rpm. After the spin coating is completed, the material is baked at 120°C to 150°C for 3 to 60 minutes. The thickness of the obtained polymer upper cladding layer 23 is 3 to 15 μm (the thickness of the upper cladding layer above the polymer optical waveguide core layer), thereby completing the preparation of a multi-port input and multi-port output polymer waveguide optical power divider based on an MMI structure.

[0022] Compared with existing device structures and preparation technologies, the present invention has the following beneficial effects:

[0023] The waveguide-type power divider of the present invention combines the characteristics of large process tolerance and small size of the MMI optical waveguide structure, and also takes advantage of the 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 using polymer materials to prepare the device is relatively simple, requiring only conventional processes such as spin coating and photolithography, without the need for more difficult processes. Moreover, the production cost is low, the efficiency is high, and it can be mass-produced, making it a power divider that can be applied in practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : A schematic structural diagram of the multi-port input optical power divider based on the MMI structure of the present invention;

[0025] Figure 2 : Figure 1 Schematic diagram of the cross section at AA';

[0026] Figure 3 : A flow chart of the preparation process of the multi-port input optical power divider of the present invention;

[0027] Figure 4 (a) A simulation diagram of the light field transmission of the multi-port input optical power divider inputted from the first input straight waveguide 1;

[0028] Figure 4 (b) 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;

[0029] Figure 4 (c) 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;

[0030] Figure 5 (a) The relationship between the normalized output power of the multi-port input optical power divider and the wavelength when the input is from the first input straight waveguide 1;

[0031] Figure 5 (b) The normalized output power of the multi-port input optical power divider varies with wavelength when inputted from the second input straight waveguide.

[0032] Figure 5 (c) The relationship between the normalized output power of the multi-port input optical power divider and the wavelength when the input is from the third input straight waveguide 3. DETAILED DESCRIPTION

[0033] Example 1

[0034] like Figure 1 As shown, the multi-port input optical power splitter consists of 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 parallel straight waveguide 5, a second S-bend waveguide 6, a first input tapered waveguide 7, a second input tapered waveguide 8, a third input tapered waveguide 9, a 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-bend waveguide 14, a second parallel straight waveguide 15, a fourth S-bend waveguide 16, a first output straight waveguide 17, a second output straight waveguide 18, and a third output straight waveguide 19.

[0035] The widths of 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 parallel straight waveguide 5, the second S-bend waveguide 6, the third S-bend waveguide 14, the second parallel straight waveguide 15, the fourth S-bend waveguide 16, the first output straight waveguide 17, the second output straight waveguide 18 and the third output straight waveguide 19 are all equal, namely, W1=4 μm; the widths of the input ends of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are all equal, namely, W1=4 μm. The widths of the output ends of the first output tapered waveguide 11, the second output tapered waveguide 12 and the third output tapered waveguide 13 are equal, namely W1=4μm; the lengths of the first input straight waveguide 1, the second input straight waveguide 2 and the third input straight waveguide 3 are equal, namely L1=500μm; the projected lengths of the first S-bend waveguide 4 and the second S-bend waveguide 6 along the first parallel straight waveguide 5 are equal, namely L2=1500μm, and the length of the first parallel straight waveguide 5 is L2=1500μm; the first input tapered waveguide 7, the second input tapered waveguide 8 and The length of the third input tapered waveguide 9 is equal to L3 = 60 μm; the width 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 multimode interference waveguide 10 is equal to W2 = 6 μm; the width W3 of the multimode interference waveguide 10 is 25 μm, and the length L4 is 1730 μm; the width W4 of the multimode interference waveguide 10 at the connection with the second output tapered waveguide 12 is 5.5 μm, and the width W5 of the multimode interference waveguide 10 at the connection with the first output tapered waveguide 11 and the third output tapered waveguide 13 is 5.5 μm. The widths of the first output tapered waveguide 11, the second output tapered waveguide 12, and the third output tapered waveguide 13 are equal, namely, L5 = 50 μm; the projected lengths of the third S-curved waveguide 14 and the fourth S-curved waveguide 16 along the second parallel straight waveguide 15 are equal, namely, L6 = 1500 μm, and the length of the second parallel straight waveguide 15 is L6 = 1500 μm; the lengths of the first output straight waveguide 17, the second output straight waveguide 18, and the third output straight waveguide 19 are equal, namely, L7 = 500 μm.

[0036] like Figure 2 As shown, Figure 1 A schematic cross-sectional view of a multi-port input optical power divider. The components are: silicon wafer substrate 20, polymer lower cladding 21, polymer optical waveguide core 22', and polymer upper cladding 23. The thickness of silicon wafer substrate 20 is 1 mm, the thickness of polymer lower cladding 21 is 5 μm, the thickness of polymer optical waveguide core 22' is 5 μm, and the thickness of upper cladding 23 (the thickness of the upper cladding layer above the polymer optical waveguide core) is 5 μm.

[0037] like Figure 4As shown in (a), the materials and waveguide dimensions used in Example 1 are selected during the simulation process. It can be clearly seen from the simulation diagram that when the input is the fundamental mode at a wavelength of 850nm, the output is the fundamental mode with the same power.

[0038] like Figure 4 As shown in (b), the materials and waveguide dimensions used in Example 1 are selected during the simulation process. It can be clearly seen from the simulation diagram that when the input is the fundamental mode at a wavelength of 850nm, the output is the fundamental mode with the same power.

[0039] Place Figure 4 As shown in (c), the materials and waveguide dimensions used in Example 1 are selected during the simulation process. It can be clearly seen from the simulation diagram that when the input is the fundamental mode at a wavelength of 850nm, the output is the fundamental mode with the same power.

[0040] like Figure 5 As shown in (a), the materials and waveguide dimensions used in Example 1 are selected. It can be seen that in the 800-900 nm band, the output power fluctuates slightly with wavelength changes, and the device is not sensitive to wavelength.

[0041] like Figure 5 As shown in (b), the materials and waveguide dimensions used in Example 1 are selected. It can be seen that in the 800-900 nm band, the output power fluctuates slightly with wavelength changes, and the device is not sensitive to wavelength.

[0042] like Figure 5 As shown in (c), the materials and waveguide dimensions used in Example 1 are selected. It can be seen that in the 800-900 nm band, the output power fluctuates slightly with wavelength changes, and the device is not sensitive to wavelength.

[0043] Example 2

[0044] The preparation method of the optical power divider with multi-port input based on MMI structure at 850nm of the present invention is as follows:

[0045] A: Cleaning of silicon wafer substrate: Wipe the silicon wafer substrate vigorously with a cotton ball soaked in acetone three times; then wipe the silicon wafer substrate vigorously with a cotton ball soaked in ethanol three times; after wiping it clean, rinse it repeatedly with deionized water, and finally blow dry the silicon wafer with nitrogen gas, then place it in a clean petri dish and seal it for storage;

[0046] B: Preparation of the polymer waveguide lower cladding layer: Diluted EpoClad polymer lower cladding material was spin-coated onto a clean silicon wafer substrate at 3000 rpm. The substrate was then baked at 120°C for 5 minutes, exposed to light for 12 seconds, and then baked again at 130°C for 30 minutes. The resulting polymer lower cladding layer had a thickness of 5 μm.

[0047] C: The polymer optical waveguide core layer 22' including the input / output region and the multimode interference region of the device is prepared by spin coating, photolithography and wet etching processes: the diluted polymer optical waveguide core layer material EpoCore is spin coated on the polymer lower cladding layer by spin coating process to form a polymer optical waveguide core layer film 22, the spin coating speed is 3000 rpm, and the thickness of the prepared polymer optical waveguide core layer film 22 is 5 μm; the prepared polymer optical waveguide core layer film 22 is pre-baked by a step-by-step temperature increase method, first baking at 50°C for 10 minutes, then baking at 95°C for 15 minutes, and then cooling after the baking; the prepared polymer optical waveguide core layer film 22 is subjected to plate-alignment photolithography, the ultraviolet light wavelength emitted by the photolithography machine is 365 nm, and the waveguide mask is the structure 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 with an exposure time of 3.5 seconds, so that the polymer optical waveguide core layer area of ​​the device input / output area, the multimode interference area, and the tapered waveguide area connecting the multimode interference area and the input / output area to be prepared is exposed to ultraviolet light; the silicon wafer after photolithography is removed from the photolithography machine and baked at 50°C for 10 minutes, then baked at 85°C for 15 minutes, and after baking, the temperature is cooled to room temperature before the next operation; the polymer optical waveguide core layer 22' structure is subjected to the following treatment: Development is performed by wet etching in a developer for 60 seconds to remove the unexposed non-polymer optical waveguide core structure, leaving only the polymer optical waveguide core structure 22' corresponding to the mask. Then, an isopropyl alcohol solution is used to wash away the developer and the polymer optical waveguide core material remaining on the silicon wafer surface. Subsequently, the remaining isopropyl alcohol on the surface is rinsed clean with deionized water and blown dry with nitrogen. Finally, a post-baking process is performed at 130°C for 40 minutes to complete the preparation of the polymer optical waveguide core layer 22' with a strip structure.

[0048] D: Preparation of the Polymer Waveguide Upper Cladding: The diluted EpoClad polymer upper cladding material was spin-coated onto the silicon wafer with the polymer waveguide core layer 22' at a speed of 3000 rpm. After spin coating, the wafer was baked at 120°C for 5 minutes, exposed to light for 12 seconds, and then baked again for 3 minutes. The resulting polymer upper cladding layer above the waveguide core layer had a thickness of 5 μm. This completed the fabrication of an 850nm MMI-structured polymer multi-port input optical power divider.

[0049] It should be noted that the specific embodiments 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 can also have more forms. For example, each power divider can be cascaded as a unit structure to achieve further expansion and application. Moreover, the materials of the design are not limited to this. Waveguide materials such as silicon, silicon nitride, and lithium niobate can also be used. Those skilled in the art who are clear about the disclosure of the present invention or who are undisputedly derived from the written description of the document fall within the scope of protection to be protected by this patent.

Claims

1. A polymer waveguide optical power divider with multi-port input and multi-port output based on an MMI structure, characterized by: From bottom to top, it is composed of a silicon wafer substrate (20), a polymer lower cladding layer (21), a polymer optical waveguide core layer (22') and a polymer upper cladding layer (23). The polymer optical waveguide core layer (22') and the polymer upper cladding layer (23) are located together on the polymer lower cladding layer (21). The polymer optical waveguide core layer (22') is completely covered in the polymer upper cladding layer (23). The refractive index of the polymer optical waveguide core layer (22') is higher than the refractive index of the polymer lower cladding layer (21) and the polymer upper cladding layer (23). The entire polymer optical waveguide core layer (22') is based on the MMI optical waveguide structure. From left to right along the propagation direction of light The invention is sequentially composed of a first input straight waveguide (1), a second input straight waveguide (2) and a third input straight waveguide (3) having the same structure and size and being parallel to each other, a first S-bend waveguide (4) and a second S-bend waveguide (6) having the same structure and size, a first parallel 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 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) having the same structure and size, and The invention relates to a multimode interference waveguide (10) comprising a fourth S-bend waveguide (16), a second parallel straight waveguide (15), a first output straight waveguide (17), a second output straight waveguide (18) and a third output straight waveguide (19) having the same structure and size and being parallel to each other; 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 multimode interference waveguide (10); the first output straight waveguide (17), the second output straight waveguide (18) and the third output straight waveguide (19) respectively serve as the three output ends of the multimode interference waveguide (10); the first input straight waveguide (1), the first S-bend waveguide (4) and the first output straight waveguide (11) are connected to the first S-bend waveguide (4) and the first output straight waveguide (11). The first input tapered waveguide (7) is connected in sequence; the second input straight waveguide (2), the first parallel straight waveguide (5) and the second input tapered waveguide (8) are connected in sequence; 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) and the first output straight waveguide (17) are connected in sequence; the second output tapered waveguide (12), the second parallel straight waveguide (15) and the second output straight waveguide (18) are connected in sequence; the third output tapered waveguide (13), the fourth S-bend waveguide (16) and the third output straight waveguide (19) are connected in sequence.

2. The polymer waveguide optical power divider with multi-port input and multi-port output based on MMI structure according to claim 1, characterized in that: The widths of 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 parallel straight waveguide (5), the second S-bend waveguide (6), the third S-bend waveguide (14), the second parallel straight waveguide (15), the fourth S-bend waveguide (16), the first output straight waveguide (17), the second output straight waveguide (18) and the third output straight waveguide (19) are equal, namely, W1=4-6 μm; the widths of the input ends of the first output tapered waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide (13) are equal, namely, W1=4-6 μm; the first output tapered waveguide (11) is equal to the width of the input ends of the second output tapered waveguide (12) and the third output tapered waveguide (13) are equal to the width of the input ends of ... first output tapered waveguide (11) The widths of the output ends of the waveguide (11), the second output tapered waveguide (12) and the third output tapered waveguide (13) are equal, namely, W1=4-6 μm; the lengths of the first input straight waveguide (1), the second input straight waveguide (2) and the third input straight waveguide (3) are equal, namely, L1=500-3000 μm; the projected lengths of the first S-bend waveguide (4) and the second S-bend waveguide (6) along the first parallel straight waveguide (5) are equal, namely, L2=800-2500 μm, and the length of the first parallel straight waveguide (5) is L2=800-2500 μm; the first input tapered waveguide (7), the second input tapered waveguide (8) and the third input tapered waveguide (9) are equal, namely, L1=500-3000 μm; the projected lengths of the first S-bend waveguide (4) and the second S-bend waveguide (6) along the first parallel straight waveguide (5) are equal, namely, L2=800-25 .... The length of the guide (9) is equal to L3 = 50 to 200 μm; the width 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 multimode interference waveguide (10) is equal to W2 = 5 to 6 μm, and W2> W1; the width W3 of the multimode interference waveguide (10) is 20 to 30 μm, and the length L4 is 1500 to 2000 μm; the width W4 of the connection between the multimode interference waveguide (10) and the second output tapered waveguide (12) is equal to 5 to 6 μm, and the width of the connection between the multimode interference waveguide (10) and the first output tapered waveguide (11) and the third output tapered waveguide (13) is equal W5 is 5 to 15 μm, and W5>W4; the lengths of the first output tapered waveguide (11), the second output tapered waveguide (12), and the third output tapered waveguide (13) are equal, namely, L5=50 to 200 μm; the projected lengths of the third S-bend waveguide (14) and the fourth S-bend waveguide (16) along the second parallel straight waveguide (15) are equal, namely, L6=800 to 2000 μm, and the length of the second parallel straight waveguide (15) is L6=800 to 2000 μm; the lengths of the first output straight waveguide (17), the second output straight waveguide (18), and the third output straight waveguide (19) are equal, namely, L7=500 to 2000 μm.

3. The polymer waveguide optical power divider with multi-port input and multi-port output based on MMI structure according to claim 1, characterized in that: The thickness of the silicon wafer substrate (20) is 0.5-1 mm, the thickness of the polymer lower cladding layer (21) is 3-15 μm, the thickness of the polymer optical waveguide core layer (22') is 2-10 μm, and the thickness of the polymer upper cladding layer (23) above the polymer optical waveguide core layer (22') is 3-15 μm.

4. The polymer waveguide optical power divider with multi-port input and multi-port output based on MMI structure according to claim 1, characterized in that: The material of the polymer lower cladding layer (21) and the polymer upper cladding layer (23) is one of polycarbonate, polyimide, polymethyl methacrylate, polyethylene, polyester, polystyrene and EpoClad; the material of the polymer optical waveguide core layer (22') is EpoCore, SU-8 2002 or SU-8 2005.

5. A method for preparing a polymer waveguide optical power divider with multi-port input and multi-port output based on an MMI structure according to claim 1, 2, 3 or 4, comprising the following steps: A: Cleaning of silicon wafer substrates Wipe the silicon wafer substrate (20) vigorously with a cotton ball soaked in acetone, and wipe it repeatedly 2 to 3 times; then wipe the silicon wafer substrate (20) vigorously with a cotton ball soaked in ethanol, and wipe it repeatedly 2 to 3 times; after wiping it clean, rinse it repeatedly with deionized water, and finally blow dry the silicon wafer with nitrogen, then put it into a clean culture dish and seal it for storage; B: Preparation of polymer optical waveguide lower cladding The polymer lower cladding material is spin-coated on a cleaned silicon wafer substrate (20) using a spin coating process, the spin coating speed is 1000 to 5000 rpm, and after the spin coating is completed, it is baked at 100° C. to 150° C. for 3 to 60 minutes; after the baking of the EpoClad material, it is first baked at 110 to 130° C. for 1 to 10 minutes, the whole is exposed for 5 to 30 seconds, and then baked at 130 to 150° C. for 2 to 50 minutes; C: Preparation of polymer optical waveguide core layer A polymer optical waveguide core layer material is spin-coated on a polymer lower cladding layer (21) by a spin coating process to form a polymer optical waveguide core layer film (22), with the spin coating speed being 1000 to 5000 rpm; the prepared polymer optical waveguide core layer film (22) is pre-baked, i.e., baked at 50°C to 180°C for 3 to 30 minutes, and then naturally cooled to room temperature after baking; the polymer optical waveguide core layer film (22) is subjected to plate-aligned photolithography, the ultraviolet light wavelength emitted by the photolithography machine is 350 to 400 nm, the waveguide mask is complementary to the structure of the polymer optical waveguide core layer (22') to be prepared, and exposure is performed when the photolithography plate is in close contact with the silicon wafer substrate, and the exposure time is 4 to 40 seconds, so that the polymer optical waveguide core layer film (22) within the structure of the polymer optical waveguide core layer (22') to be prepared is exposed to ultraviolet light; The photolithographic silicon wafer substrate is removed from the photolithography machine for intermediate baking, i.e., baking at 50°C to 180°C for 5 to 30 minutes, and then naturally cooling to room temperature after baking; the polymer optical waveguide core layer (22') structure is developed, i.e., first wet-etching in a developer corresponding to the polymer optical waveguide core layer material for 10 to 60 seconds to remove the unexposed polymer optical waveguide core layer film (22), leaving only the polymer optical waveguide core layer (22') structure corresponding to the mask, and then washing away the developer and the polymer optical waveguide core layer material remaining on the surface of the silicon wafer with an isopropyl alcohol solution, then rinsing the isopropyl alcohol remaining on the surface with deionized water and drying with nitrogen; finally, baking at a temperature of 120°C to 150°C for 30 to 60 minutes to perform post-baking to harden the film, thereby completing the preparation of the polymer optical waveguide core layer (22') with a strip structure; D: Preparation of the upper cladding layer of polymer optical waveguide The polymer upper cladding material is spin-coated on the waveguide core layer (22') and the polymer lower cladding layer (21) by a spin coating process, the spin coating speed is 1000 to 5000 rpm, and after the spin coating is completed, the polymer upper cladding layer (23) is baked at 120°C to 150°C for 3 to 60 minutes to complete the preparation of the multi-port input and multi-port output polymer waveguide optical power divider based on the MMI structure.

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