A tunable dual-mode six-port optical power splitter and a method for manufacturing the same

Abstract

The application discloses a tunable dual-mode six-port optical power divider and a preparation method thereof, and belongs to the technical field of planar optical waveguide devices. From bottom to top, the six-port optical power divider is composed of a silicon wafer substrate, a polymer lower cladding layer prepared on the silicon wafer substrate, a strip-shaped polymer optical waveguide core layer prepared on the polymer lower cladding layer, and a polymer upper cladding layer prepared on the polymer lower cladding layer and the polymer optical waveguide core layer; the refractive index of the polymer optical waveguide core layer material is higher than the refractive index of the polymer upper and lower cladding layer materials, and the polymer optical waveguide core layer is based on MZI and MMI optical waveguide structures. The application realizes the purpose of tunable power distribution of two optical modes from different output ports at the same time; in addition, the process of preparing the device by using polymer materials is relatively simple, only needs conventional processes such as spin coating and photoetching, does not need high-difficulty processes, and has the advantages of low production cost, high efficiency and large-scale batch production, and is a mode power divider that can be applied to actual use.

Description

Technical Field

[0001] This invention belongs to the field of planar optical waveguide device technology, specifically relating to a tunable dual-mode six-port optical power divider and its fabrication method, which uses a silicon wafer substrate as the substrate and organic polymer materials with high thermo-optic coefficients and different refractive indices as the polymer optical waveguide core and cladding. Background Technology

[0002] With the rapid development of internet technologies such as cloud computing, big data, and the Internet of Things, people's demands for information transmission speed and capacity are constantly increasing. Traditional electrical interconnects face significant challenges in further improving data transmission capabilities due to crosstalk between channels and severe losses caused by high frequencies. The introduction of optical interconnects has become key to solving this problem. Optical interconnects offer numerous advantages, such as high information transmission speed, low power consumption, low transmission loss, and high security. Furthermore, the use of multiplexing technologies such as wavelength division multiplexing (WDM) and mode division multiplexing (MDM) can further improve the transmission capacity of a single physical channel. MDM, as one of the key technologies for improving channel capacity, has already been widely applied.

[0003] An optical power divider is a device capable of distributing and combining optical signals. It is one of the most fundamental components of optical integrated devices and can also perform signal monitoring functions. Mode-based optical power dividers based on planar waveguide structures are an important branch of optical power dividers. They are not only compatible with optical fibers but also possess advantages such as compact structure, tunability, low insertion loss, low mode correlation loss, flexible design, and a wide variety of types. Due to the use of photolithography, these dividers can achieve highly complex functions in a very small area, resulting in extremely high integration. However, traditional optical power dividers can only distribute and combine power to the fundamental mode, and the output ports are fixed. The position and number of output ports cannot be changed through thermal tuning; they can only be cascaded, which significantly increases the device size. This limits their application in mode-division multiplexing systems, thus restricting further increases in optical communication data transmission capacity. Therefore, there is an urgent need for a tunable multi-port optical power divider capable of distributing power to two modes.

[0004] Material systems used to fabricate planar optical waveguide power dividers include silicon, silicon dioxide, and polymers. Compared to inorganic materials, polymer materials offer advantages such as simpler fabrication processes and lower costs for planar optical waveguide devices. Furthermore, polymer materials possess characteristics such as high thermo-optic coefficients, low dielectric constants, high optical damage thresholds, and compatibility with semiconductor processes. Polymer materials can also be functionally doped to obtain desired superior performance, demonstrating promising development prospects. Summary of the Invention

[0005] To overcome the shortcomings of traditional optical power dividers that only support single-mode and whose output ports cannot be changed, the present invention aims to provide a tunable six-port optical power divider that can handle two optical modes and its fabrication method.

[0006] This invention employs the traditional Mach-Zehnder interferometer (MZI) structure and the multimode interference (MMI) optical waveguide structure. MZI and MMI are widely used in the structural design of planar optical waveguide devices, considered fundamental components and easily implemented waveguide interferometer schemes. They have significant application value in optical communication and planar optical waveguide mode power dividers. A traditional MZI optical waveguide mainly consists of a single-mode waveguide-based input / output straight waveguide, a Y-branch 3-dB beam splitter / coupler, and two parallel interference arms. The MMI structure comprises an input waveguide, a multimode interference waveguide, and an output waveguide, utilizing the self-image principle to achieve power distribution. However, devices based on these two traditional structures often only achieve modulation of the fundamental mode signal or conversion between the fundamental and higher-order modes, unable to simultaneously modulate both the fundamental and higher-order modes. Furthermore, the output port position and number are not adjustable, thus limiting the application of this structure in mode-division multiplexing systems.

[0007] This invention uses a silicon wafer as the substrate, organic polymer materials as the upper and lower cladding layers of the optical waveguide, and organic polymer materials with different refractive indices for the polymer waveguide core layer. The refractive index of the polymer material used to fabricate the polymer waveguide core layer is higher than that of the polymer materials in the upper and lower cladding layers. This design fully utilizes the diversity, excellent processing performance, low cost, and performance enhancement advantages of existing polymer materials through doping. The fabrication process is simple and easy to implement, compatible with semiconductor processes, easy to integrate, and suitable for large-scale production. Therefore, this invention has significant practical application value.

[0008] The technical solution adopted by this invention to solve its technical problem is as follows:

[0009] As attached Figure 1 As shown (for) Figure 2 (Cross-sectional view at position A-A') The tunable six-port optical power divider of the present invention comprises, from bottom to top, a silicon substrate 25, a polymer lower cladding layer 26 prepared on the silicon substrate 25 by spin coating, a strip-shaped polymer waveguide core layer 27 prepared on the polymer lower cladding layer 26 by spin coating, photolithography, and wet etching, a polymer upper cladding layer 28 prepared on the polymer lower cladding layer 26 and the polymer waveguide core layer 27 by spin coating, and a metal electrode 24 prepared on the polymer upper cladding layer 28 by vacuum evaporation, spin coating, photolithography, and wet etching.

[0010] As attached Figure 2As shown, the polymer waveguide core 27 of the tunable six-port optical power divider of the present invention is based on MZI and MMI optical waveguide structures. From left to right along the light propagation direction, it consists of an input few-mode straight waveguide 1 (capable of transmitting E...). 11 and E 12 1. Input tapered waveguide 2. First S-bend waveguide with the same structure and size 3. Second S-bend waveguide 4. First straight waveguide with the same structure and size and parallel to each other 5. Second straight waveguide 6. Third S-bend waveguide with the same structure and size 7. and fourth S-bend waveguide 8. First coupling arm waveguide with the same structure and size and parallel to each other 9. and second coupling arm waveguide 10. Fifth S-bend waveguide with the same structure and size 11. and sixth S-bend waveguide 12. First phase shifter straight waveguide with the same structure and size and parallel to each other 13. and second phase shifter straight waveguide 14. First S-bend waveguide with the same structure and size The waveguide consists of tapered waveguide 15 and 16, multimode interference waveguide 17, third tapered waveguide 29 and eighth tapered waveguide 34 (with identical structure and size), fourth tapered waveguide 30 and seventh tapered waveguide 33 (with identical structure and size), fifth tapered waveguide 31 and sixth tapered waveguide 32 (with identical structure and size), first output waveguide 18 and sixth output waveguide 23 (with identical structure and size), second output waveguide 19 and fifth output waveguide 22 (with identical structure and size), and third output waveguide 20 and fourth output waveguide 21 (with identical structure and size), and is connected to the second straight waveguide 6. A metal heating electrode 24 is fabricated on the polymer cladding 28. The first S-bend waveguide 3, the first straight waveguide 5, the third S-bend waveguide 7, the first coupling arm waveguide 9, the fifth S-bend waveguide 11, the first phase shifter straight waveguide 13, and the first tapered waveguide 15 are sequentially connected and then connected to the multimode interference waveguide 17. The second S-bend waveguide 4, the second straight waveguide 6, the fourth S-bend waveguide 8, the second coupling arm waveguide 10, the sixth S-bend waveguide 12, the second phase shifter straight waveguide 14, and the second tapered waveguide 16 are sequentially connected and then connected to the multimode interference waveguide 17. Interference waveguide 17 is connected to first output waveguide 18, sixth output waveguide 23, second output waveguide 19, fifth output waveguide 22, third output waveguide 20, and fourth output waveguide 21 via third tapered waveguide 29, eighth tapered waveguide 34, fourth tapered waveguide 30, seventh tapered waveguide 33, fifth tapered waveguide 31, and sixth tapered waveguide 32, respectively. First output waveguide 18, sixth output waveguide 23, second output waveguide 19, fifth output waveguide 22, third output waveguide 20, and fourth output waveguide 21 constitute the six output terminals of multimode interference waveguide 17.

[0011] The following components are defined: input few-mode straight waveguide 1, first S-bend waveguide 3, second S-bend waveguide 4, first straight waveguide 5, second straight waveguide 6, third S-bend waveguide 7, fourth S-bend waveguide 8, first coupling arm waveguide 9, second coupling arm waveguide 10, fifth S-bend waveguide 11, sixth S-bend waveguide 12, first phase shifter straight waveguide 13, second phase shifter straight waveguide 14, the connection point between input few-mode straight waveguide 1 and input tapered waveguide 2, the connection point between first phase shifter straight waveguide 13 and first tapered waveguide 15, the connection point between second phase shifter straight waveguide 14 and second tapered waveguide 16, the output end of first output waveguide 18, the output end of sixth output waveguide 23, the output end of second output waveguide 19, the output end of fifth output waveguide 22, the output end of third output waveguide 20, and the width of the output end of fourth output waveguide 21. The same, ranging from 3 to 11 μm.

[0012] Input the length of the few-mode straight waveguide 1 The width at the connection between the input tapered waveguide 2 and the first S-bend waveguide 3 and the second S-bend waveguide 4 is 500~3000μm. It is 6~15μm, and =2 The length of the input tapered waveguide 2 (the projected length in the direction parallel to the axis of symmetry of the first coupled arm waveguide 9 and the second coupled arm waveguide 10 is defined as the length of the tapered waveguide and the curved waveguide) The lengths are 400~1600μm; the lengths of the first S-bend waveguide 3 and the second S-bend waveguide 4, the first straight waveguide 5, the second straight waveguide 6, and the length of the metal heating electrode 24. and Equal lengths of 800~2500μm; lengths of the third S-bend waveguide 7 and the fourth S-bend waveguide 8 The lengths of the fifth S-bend waveguide 11 and the sixth S-bend waveguide 12 The lengths are the same, ranging from 500 to 2200 μm; the lengths of the first coupling arm waveguide 9 and the second coupling arm waveguide 10 are... Equal lengths, ranging from 200 to 1200 μm; the lengths of the first phase shifter straight waveguide 13 and the second phase shifter straight waveguide 14 are... Equal in width, ranging from 200 to 1400 μm; the width at the junction of the first tapered waveguide 15, the second tapered waveguide 16, and the multimode interference waveguide 17. The lengths are the same, ranging from 5 to 15 μm; the lengths of the first tapered waveguide 15 and the second tapered waveguide 16 are also the same. Equal in width, ranging from 150 to 900 μm; the width of multimode interference waveguide 17 The length is 40~120μm. The lengths are 2500~4800μm; the lengths of the first output waveguide 18, the sixth output waveguide 23, the second output waveguide 19, the fifth output waveguide 22, the third output waveguide 20, and the fourth output waveguide 21 are 2500~4800μm. Equal in size, ranging from 800 to 2500 μm; the width of the metal heating electrode 24 The lengths are 4~12μm. The lengths of the third conical waveguide 29, the eighth conical waveguide 34, the fourth conical waveguide 30, the seventh conical waveguide 33, the fifth conical waveguide 31, and the sixth conical waveguide 32 are also shown. Equal in width, ranging from 150 to 900 μm; the width at the junction of the third tapered waveguide 29, the eighth tapered waveguide 34, and the multimode interference waveguide 17. The widths at the junctions of the fifth tapered waveguide 31, the sixth tapered waveguide 32, and the multimode interference waveguide 17 are the same, ranging from 7 to 18 μm. The widths at the junctions of the fourth tapered waveguide 30, the seventh tapered waveguide 33, and the multimode interference waveguide 17 are the same, ranging from 6 to 15 μm. The widths at the connections between the third tapered waveguide 29, the eighth tapered waveguide 34, the fourth tapered waveguide 30, the seventh tapered waveguide 33, the fifth tapered waveguide 31, the sixth tapered waveguide 32 and the first output waveguide 18, the sixth output waveguide 23, the second output waveguide 19, the fifth output waveguide 22, the third output waveguide 20, and the fourth output waveguide 21 are equal. .

[0013] The signal light is input from the input few-mode straight waveguide 1, and after passing through the input tapered waveguide 2, it is split into two signal beams, which enter the first S-bend waveguide 3 and the second S-bend waveguide 4 respectively. Then, they enter the first coupling arm waveguide 9 and the second coupling arm waveguide 10 through the first straight waveguide 5 and the second straight waveguide 6, the third S-bend waveguide 7 and the fourth S-bend waveguide 8 respectively, where they are coupled. When no voltage is applied to the metal electrode 24, i.e., the temperature difference ΔT of the metal electrode 24 is 0... In case K, the signal light coupled in the first coupling arm waveguide 9 and the second coupling arm waveguide 10 is evenly split into two beams, which pass through the fifth S-bend waveguide 11 and the sixth S-bend waveguide 12, the first phase shifter straight waveguide 13 and the second phase shifter straight waveguide 14, the first tapered waveguide 15 and the second tapered waveguide 16 respectively, and enter the multimode interference waveguide 17 to excite multiple optical modes and interfere with each other. Subsequently, they pass through the third tapered waveguide 29, the eighth tapered waveguide 34, the fourth tapered waveguide 30, the seventh tapered waveguide 33, the fifth tapered waveguide 31, and the sixth tapered waveguide 32 respectively, and enter the first output waveguide 18, the sixth output waveguide 23, the second output waveguide 19, the fifth output waveguide 22, the third output waveguide 20 and the fourth output waveguide 21 for medium power output; when a voltage is applied to the metal electrode 24, i.e., the temperature difference ΔT before and after the voltage is applied to the metal electrode 24 is 4.5. In case K, the signal light coupled in the first coupling arm waveguide 9 and the second coupling arm waveguide 10 is completely coupled into the sixth S-bend waveguide 12. It then enters the multimode interference waveguide 17 via the second phase shifter straight waveguide 14 and the second tapered waveguide 16, exciting multiple optical modes that interfere with each other. Subsequently, it enters the first output waveguide 18, the fourth output waveguide 21, and the fifth output waveguide 22 via the third tapered waveguide 29, the sixth tapered waveguide 32, and the seventh tapered waveguide 33, respectively, for equal-power output. (When no voltage is applied to the electrodes, the signal light enters the multimode interference waveguide 17 from the two ports of the first tapered waveguide 15 and the second tapered waveguide 16 at equal power, exciting multiple optical modes that interfere with each other, resulting in equal-power output from all six ports; while when voltage is applied to the electrodes and the temperature difference ΔT = 4.5...) When K is applied, the signal light enters the multimode interference waveguide 17 from only one port of the second tapered waveguide 16. Due to the change in the input position and energy of the signal light, the multiple optical modes excited in the multimode interference waveguide 17 are also different, thus realizing output from different ports. When a voltage is applied to the metal electrode 24, the temperature difference ΔT before and after the voltage is applied to the metal electrode 24 is 13.At 5 K, the signal light coupled in the first coupling arm waveguide 9 and the second coupling arm waveguide 10 is fully coupled into the fifth S-bend waveguide 11. It then enters the multimode interference waveguide 17 via the first phase shifter straight waveguide 13 and the first tapered waveguide 15, exciting multiple optical modes that interfere with each other. Subsequently, it enters the second output waveguide 19, the third output waveguide 20, and the sixth output waveguide 23 via the fourth tapered waveguide 30, the fifth tapered waveguide 31, and the eighth tapered waveguide 34, respectively, for medium-power output. (The reason the signal light outputs from different waveguides is similar to the reason when the temperature difference ΔT = 4.5 K is applied before and after voltage is applied to the metal electrode 24; that is, when voltage is applied to the electrode and the temperature difference ΔT = 13.5 K, the signal light enters the multimode interference waveguide 17 only from one port of the first tapered waveguide 15). Regardless of whether voltage is applied for modulation, the mode of the output signal light is the same as the mode of the input signal light, i.e., input E. 11 The mode also outputs E. 11 Mode; Enter E 12 The mode also outputs E. 12 model.

[0014] The thickness of the silicon substrate 25 is 0.5~1mm, the thickness of the polymer lower cladding layer 26 is 3~15μm, the thickness of the polymer waveguide core layer 27 is 4~13μm, the thickness of the polymer upper cladding layer 28 above the polymer waveguide core layer 27 is 3~15μm, and the thickness of the metal (Al, Au, etc.) metal electrode 24 is 50~400 nm.

[0015] The fabrication process of the tunable six-port optical power divider described in this invention is shown in the attached diagram. Figure 4 The specific steps are as follows:

[0016] A: Cleaning of silicon wafer substrates

[0017] Wipe the silicon substrate 25 vigorously with a cotton ball soaked in acetone, repeating 2-3 times. Then wipe the silicon substrate vigorously with a cotton ball soaked in ethanol, repeating 2-3 times. After wiping it clean, rinse it thoroughly with deionized water. Finally, dry the silicon substrate with nitrogen gas, then place it in a clean petri dish and seal it.

[0018] B: Preparation of the polymer lower cladding layer

[0019] A polymer undercoating material (which is a series of transparent organic polymer materials including polycarbonate (PC), polyimide (PI), polymethyl methacrylate (PMMA), polyethylene (PE), polyester (PET), polystyrene (PS), EpoClad, etc.) is spin-coated onto a clean silicon wafer substrate 25 using a spin-coating process. The spin-coating speed is 1000~5000 rpm. After spin-coating, the substrate is baked at 120~150℃ for 3~60 minutes (for special materials such as EpoClad, after baking, the entire substrate needs to be exposed for 5~60 seconds, and then baked at 120~150℃ for 3~60 minutes). The thickness of the resulting polymer undercoating 26 is 3~15μm.

[0020] C: Fabrication of the polymer optical waveguide core layer

[0021] A polymer waveguide core material (which is a series of wet-etchable UV negative photoresist materials including EpoCore, SU-8 2002, and SU-8 2005, with a refractive index higher than that of the polymer upper and lower cladding materials) is spin-coated onto the polymer lower cladding 26 to form a polymer waveguide core film 27'. The spin-coating speed is 1000~5000 rpm, and the thickness of the resulting polymer waveguide core film 27' is 4~13 μm. The resulting polymer waveguide core film 27' is pre-baked at 50~180℃ for 3~30 minutes, and then allowed to cool naturally to room temperature. The polymer waveguide core film 27' is then subjected to photolithography, using UV light with a wavelength of 350~400 nm emitted by the photolithography machine. The waveguide mask and the structure of the polymer waveguide core film 27' to be prepared are complementary (e.g., ...). Figure 2 As shown), exposure is performed when the waveguide mask is firmly attached to the silicon substrate. The exposure time is 4-40 seconds, so that the polymer waveguide core layer film 27' within the polymer waveguide core layer 27 structure to be fabricated is exposed to ultraviolet light. The photolithographically lithographically formed silicon substrate is removed from the photolithography machine and baked at 50-180℃ for 5-30 minutes. After baking, it is allowed to cool naturally to room temperature. The polymer waveguide core layer 27 structure is developed by wet etching in the developer corresponding to the polymer waveguide core layer material for 15-80 seconds to remove... The polymer waveguide core layer film 27', which is not exposed, is left as is only the polymer waveguide core layer 27 structure corresponding to the waveguide mask. Then, the polymer waveguide core layer film 27' remaining on the silicon substrate surface is washed away with isopropanol solution to remove the developer and the residual polymer waveguide core layer film 27'. Subsequently, the residual isopropanol on the surface is rinsed away with deionized water and dried with nitrogen. Finally, it is baked at 120~150℃ for 30~60 minutes for post-baking hardening, thereby completing the fabrication of the strip-shaped polymer waveguide core layer 27.

[0022] D: Preparation of the polymer overcoat

[0023] A polymer top cladding material (which is a series of transparent organic polymer materials including polycarbonate (PC), polyimide (PI), polymethyl methacrylate (PMMA), polyethylene (PE), polyester (PET), polystyrene (PS), EpoClad, etc.; in the same device, the polymer top cladding material and the polymer bottom cladding material can be the same or different) is spin-coated onto the polymer waveguide core layer 27 and the polymer bottom cladding layer 26. The spin-coating speed is 1000~5000 rpm. After spin-coating, the material is baked at 120~150℃ for 3~60 minutes. The thickness of the polymer top cladding layer 28 on the polymer waveguide core layer 27 is 3~15μm.

[0024] E: Fabrication of the metal heating electrode 24

[0025] A metal electrode film 35 with a thickness of 50-400 nm is deposited on the polymer cladding layer 28 using a vacuum evaporation process. Then, a positive photoresist BP 212 with a thickness of 1-3 µm is spin-coated onto the metal electrode film 35 at a rotation speed of 1000-3000 rpm. The device with the spin-coated photoresist BP 212 is heated at 70℃-100℃ for 10-30 minutes, and then cooled to 20-30℃. Next, a photolithography process is performed, with the photomask having the same structure as the metal heating electrode 24 to be prepared (e.g., ...). Figure 2 As shown in the diagram, the device is exposed to ultraviolet light with a wavelength of 350-400 nm for 1-5 seconds to expose the photoresist BP 212 film in areas other than the metal heating electrode 24. After exposure, the device is immersed in a 2-5‰ NaOH solution for 10-60 seconds to remove the exposed photoresist BP 212 film. It is then rinsed with deionized water and dried with nitrogen. The device is then heated again at 80-120 °C for 10-30 minutes, followed by cooling to 20-30 °C. Next, the metal heating electrode 24 is developed by immersing the device in a 2-5‰ NaOH solution for 1-15 minutes to remove the electrode film in areas other than the metal heating electrode 24. The device is then rinsed repeatedly with deionized water and dried with nitrogen. Finally, the device is immersed in ethanol for 3-10 seconds to remove the unexposed photoresist BP 212 film on the metal heating electrode 24. The 212 film is then rinsed clean with deionized water and dried with nitrogen gas to obtain the tunable dual-mode six-port optical power divider described in this invention.

[0026] Compared with existing device structures and fabrication techniques, the advantages of this invention are:

[0027] The waveguide-type mode power divider of this invention combines the advantages of large tolerance and small size of MMI optical waveguide structure technology, and also takes advantage of the wide variety of organic polymer materials to achieve tunable and simultaneous power distribution of two optical modes from different output ports. In addition, the process of fabricating devices using polymer materials is relatively simple, requiring only conventional processes such as spin coating and photolithography, without the need for more difficult processes. Moreover, it has low production cost, high efficiency, and can be mass-produced, making it a mode power divider that can be applied in practice. Attached Figure Description

[0028] Figure 1 The present invention describes an E-based structure based on an MMI architecture. 11 and E 12 Cross-sectional structure of a dual-mode six-port optical power divider (mode) Figure 2 (Diagram of section AA')

[0029] Figure 2 The present invention describes an E-based structure based on an MMI architecture. 11 and E 12 Schematic diagram of the polymer waveguide core structure of a dual-mode six-port optical power divider;

[0030] Figure 3 : Flowchart of the fabrication process of the tunable dual-mode six-port optical power divider described in this invention;

[0031] Figure 4 (a): E in the tunable dual-mode six-port optical power divider of the present invention 11 Simulated light field distribution diagram of the model;

[0032] Figure 4 (b): E in the tunable dual-mode six-port optical power divider of the present invention 12 Simulated light field distribution diagram of the model;

[0033] Figure 5 (a): The tunable dual-mode six-port optical power divider input E of the present invention 11 The curve showing the change in output power during the mode as a function of the heating temperature ΔT of the metal heating electrode 24;

[0034] Figure 5 (b): The tunable dual-mode six-port optical power divider input E of the present invention 12 The curve showing the change in output power during the mode as a function of the heating temperature ΔT of the metal heating electrode 24;

[0035] Figure 6(a): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=0K. 11 Simulation diagram of optical field transmission in the mode;

[0036] Figure 6 (b): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=4.5 K. 11 Simulation diagram of optical field transmission in the mode;

[0037] Figure 6 (c): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT = 13.5 K. 11 Simulation diagram of optical field transmission in the mode;

[0038] Figure 7 (a): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=0K. 12 Simulation diagram of optical field transmission in the mode;

[0039] Figure 7 (b): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=4.5 K. 12 Simulation diagram of optical field transmission in the mode;

[0040] Figure 7 (c): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT = 13.5 K. 12 Simulation diagram of optical field transmission in the mode;

[0041] Figure 8 (a): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=0K. 11 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0042] Figure 8 (b): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=4.5 K. 11 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0043] Figure 8 (c): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT = 13.5 K. 11 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0044] Figure 9 (a): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=0K. 12 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0045] Figure 9 (b): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT=4.5 K. 12 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0046] Figure 9 (c): The tunable dual-mode six-port optical power divider of the present invention has a metal heating electrode with input E when ΔT = 13.5 K. 12 The curve showing the relationship between the normalized output power of the mode and wavelength;

[0047] Figure 10 (a): Microscopic plan view of the connection between the tunable dual-mode six-port optical power divider (MMI) and the output waveguide described in this invention;

[0048] Figure 10 (b): Microscopic cross-sectional view of the waveguide at the directional coupling point (at the axis of symmetry of the first coupling arm waveguide 9 and the second coupling arm waveguide 10) of the tunable dual-mode six-port optical power divider of the present invention.

[0049] like Figure 1 As shown, the names of each component are: silicon substrate 25, polymer lower cladding 26, polymer waveguide core layer 27, polymer upper cladding 28, and metal heating electrode 24.

[0050] like Figure 2As shown, the names of each component are: Input few-mode straight waveguide 1, Input tapered waveguide 2, First S-bend waveguide 3 and Second S-bend waveguide 4 with the same structure and size, First straight waveguide 5 and Second straight waveguide 6 with the same structure and size and parallel to each other, Third S-bend waveguide 7 and Fourth S-bend waveguide 8 with the same structure and size, First coupling arm waveguide 9 and Second coupling arm waveguide 10 with the same structure and size and parallel to each other, Fifth S-bend waveguide 11 and Sixth S-bend waveguide 12 with the same structure and size, First phase shifter straight waveguide 13 and Second phase shifter straight waveguide 14 with the same structure and size and parallel to each other. 14. First tapered waveguide 15 and second tapered waveguide 16. Multimode interference waveguide 17. Third tapered waveguide 29 and eighth tapered waveguide 34. Fourth tapered waveguide 30 and seventh tapered waveguide 33. Fifth tapered waveguide 31 and sixth tapered waveguide 32. First output waveguide 18 and sixth output waveguide 23. Second output waveguide 19 and fifth output waveguide 22. Third output waveguide 20 and fourth output waveguide 21. Metal heating electrode 24.

[0051] like Figure 3 As shown in the figure, 25 is a silicon wafer substrate, 26 is a polymer lower cladding layer prepared by spin coating, 27 is a polymer waveguide core layer prepared by spin coating, photolithography, and wet etching, 28 is a polymer upper cladding layer prepared by spin coating, and 24 is a metal heating electrode prepared by aluminum evaporation, spin coating of BP212 photoresist, photolithography, and wet etching.

[0052] Figure 4 (a): E in the input few-mode straight waveguide 1 of the tunable dual-mode six-port optical power divider 11 The simulation diagram of the optical field distribution of the mode shows that, in the simulation process, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagram that the optical field is mainly concentrated in the rectangular waveguide core layer, thus ensuring E... 11 The mode optical signal is effectively transmitted in the optical waveguide;

[0053] Figure 4 (b): E in the input few-mode straight waveguide 1 of the tunable dual-mode six-port optical power divider 12 The simulation diagram of the optical field distribution of the mode shows that, in the simulation process, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagram that the optical field is mainly concentrated in the rectangular waveguide core layer, thus ensuring E... 12 Optical signals are effectively transmitted in optical waveguides;

[0054] Figure 5 (a): Tunable dual-mode six-port optical power divider input E 11The curve showing the change in output power during the mode as a function of the heating temperature ΔT of the metal heating electrode 24;

[0055] Figure 5 (b): Tunable dual-mode six-port optical power divider input E 12 The curve showing the change in output power during the mode as a function of the heating temperature ΔT of the metal heating electrode 24;

[0056] Figure 6 (a): Tunable dual-mode six-port optical power divider with metal heating electrode at ΔT=0 K, input E 11 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 11 In mode, the output is the same power E. 11 model;

[0057] Figure 6 (b): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 4.5 K, input E 11 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 11 In mode, the output is the same power E. 11 model;

[0058] Figure 6 (c): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 13.5 K, input E 11 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 11 In mode, the output is the same power E. 11 model;

[0059] Figure 7 (a): Tunable dual-mode six-port optical power divider with metal heating electrode at ΔT=0 K, input E 12 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 12 In mode, the output is the same power E. 12 model;

[0060] Figure 7(b): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 4.5 K, input E 12 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 12 In mode, the output is the same power E. 12 model;

[0061] Figure 7 (c): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 13.5 K, input E 12 The simulation diagrams show the optical field transmission of the mode and the optical field distribution at the output port. During the simulation, we used the same materials and waveguide dimensions as in Example 1. It is clear from the simulation diagrams that the input E... 12 In mode, the output is the same power E. 12 model;

[0062] Figure 8 (a): Tunable dual-mode six-port optical power divider with metal heating electrode at ΔT=0 K, input E 11 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0063] Figure 8 (b): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 4.5 K, input E 11 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0064] Figure 8 (c): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 13.5 K, input E 11 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0065] Figure 9 (a): Tunable dual-mode six-port optical power divider with metal heating electrode at ΔT=0 K, input E 12 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0066] Figure 9(b): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 4.5 K, input E 12 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0067] Figure 9 (c): Tunable dual-mode six-port optical power divider with metal heated electrodes at ΔT = 13.5 K, input E 12 The curve showing the relationship between the normalized output power of the mode and wavelength indicates that in the C-band, the output power fluctuates less with wavelength, and the device is not sensitive to wavelength.

[0068] Figure 10 (a): Microscopic plan view of the connection between the tunable dual-mode six-port optical power divider (MMI) and the output waveguide. In the experiment, we used the materials and waveguide dimensions selected in Example 1. As can be seen from the microscopic image, the waveguide morphology is good and the dimensions are basically consistent with those selected in Example 1.

[0069] Figure 10 (b): Microscopic cross-sectional view of the waveguide at the directional coupling of the tunable dual-mode six-port optical power divider. In the experiment, we used the materials and waveguide dimensions selected in Example 1. As can be seen from the microscopic image, the waveguide morphology is good and the dimensions are basically consistent with those selected in Example 1. Detailed Implementation

[0070] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0071] Example 1:

[0072] As attached Figure 1 As shown, it is composed of a silicon wafer substrate 25, a polymer lower cladding layer 26 prepared on the silicon wafer substrate 25, a strip-shaped polymer waveguide core layer 27 prepared on the polymer lower cladding layer 26, a polymer upper cladding layer 28 prepared on the polymer waveguide core layer 27, and a metal heating electrode 24 prepared on the polymer upper cladding layer 28.

[0073] like Figure 2As shown, the widths of the following waveguides are as follows: input few-mode straight waveguide 1, first S-bend waveguide 3, second S-bend waveguide 4, first straight waveguide 5, second straight waveguide 6, third S-bend waveguide 7, fourth S-bend waveguide 8, first coupling arm waveguide 9, second coupling arm waveguide 10, fifth S-bend waveguide 11, sixth S-bend waveguide 12, first phase shifter straight waveguide 13, second phase shifter straight waveguide 14, the connection between input few-mode straight waveguide 1 and input tapered waveguide 2, the connection between first phase shifter straight waveguide 13 and first tapered waveguide 15, the connection between second phase shifter straight waveguide 14 and second tapered waveguide 16, the output terminals of first output waveguide 18, sixth output waveguide 23, second output waveguide 19, fifth output waveguide 22, third output waveguide 20, and fourth output waveguide 21. Same length, 5μm; length of input few-mode straight waveguide 1 It is 2000μm.

[0074] The width at the connection point between the input tapered waveguide 2 and the first S-bend waveguide 3 and the second S-bend waveguide 4 The length of the input tapered waveguide 2 is 10 μm; the projected length in the direction parallel to the axis of symmetry of the first coupled arm waveguide 9 and the second coupled arm waveguide 10 is defined as the length of the tapered waveguide and the curved waveguide. The length is 900 μm; the lengths of the first S-bend waveguide 3 and the second S-bend waveguide 4, the first straight waveguide 5, the second straight waveguide 6, and the metal heating electrode 24 are all 900 μm long. and The lengths are equal to 1700 μm; the lengths of the third S-bend waveguide 7 and the fourth S-bend waveguide 8 are also equal. The lengths of the fifth S-bend waveguide 11 and the sixth S-bend waveguide 12 The same length, 1240 μm; the lengths of the first coupling arm waveguide 9 and the second coupling arm waveguide 10 are also the same. Equal lengths, both 530 μm; the lengths of the first phase shifter straight waveguide 13 and the second phase shifter straight waveguide 14 are also equal. Equal to each other, both being 500 μm; the width at the junction of the first tapered waveguide 15, the second tapered waveguide 16, and the multimode interference waveguide 17. The lengths of the first tapered waveguide 15 and the second tapered waveguide 16 are the same, both being 8 μm. Equal to 400 μm; the width of multimode interference waveguide 17 It is 86μm in length. The lengths of the first output waveguide 18, the sixth output waveguide 23, the second output waveguide 19, the fifth output waveguide 22, the third output waveguide 20, and the fourth output waveguide 21 are 3500 μm. Equal to 1650 μm; the width of the metal heating electrode 24 The length is 10 μm. The lengths of the third conical waveguide 29, the eighth conical waveguide 34, the fourth conical waveguide 30, the seventh conical waveguide 33, the fifth conical waveguide 31, and the sixth conical waveguide 32 are also shown. Equal to 400 μm; the width at the connection between the third tapered waveguide 29, the eighth tapered waveguide 34 and the multimode interference waveguide 17. The same, 12μm; the width at the connection between the fifth tapered waveguide 31, the sixth tapered waveguide 32 and the multimode interference waveguide 17. The same width is 10 μm; the width at the connection between the fourth tapered waveguide 30, the seventh tapered waveguide 33 and the multimode interference waveguide 17 is also 10 μm. The widths at the connections between the third tapered waveguide 29, the eighth tapered waveguide 34, the fourth tapered waveguide 30, the seventh tapered waveguide 33, the fifth tapered waveguide 31, the sixth tapered waveguide 32 and the first output waveguide 18, the sixth output waveguide 23, the second output waveguide 19, the fifth output waveguide 22, the third output waveguide 20, and the fourth output waveguide 21 are the same, at 8μm. That is, 2.5μm.

[0075] The silicon substrate 25 has a thickness of 1 mm, the polymer lower cladding layer 26 has a thickness of 5 μm, the polymer waveguide core layer 27 has a thickness of 9 μm, the polymer upper cladding layer 28 above the polymer waveguide core layer 27 has a thickness of 5 μm, and the metal heating electrode 24 has a thickness of 200 nm.

[0076] Example 2:

[0077] The present invention describes a transmissible E based on an MMI structure. 11 E 12 The fabrication method of the dual-mode six-port optical power divider is as follows:

[0078] (1) Cleaning of silicon wafer substrate: Wipe the silicon wafer substrate 25 vigorously with a cotton ball soaked in acetone, repeat 3 times, then wipe the silicon wafer substrate vigorously with a cotton ball soaked in ethanol, repeat 3 times. After wiping clean, rinse it repeatedly with deionized water, and finally blow the silicon wafer substrate dry with nitrogen gas. Then put it into a clean petri dish and seal it.

[0079] (2) Preparation of polymer undercoat: The EpoClad polymer undercoat material was spin-coated onto the cleaned silicon wafer substrate 25 using a spin-coating process. The spin-coating speed was 4000 rpm. After spin-coating, the substrate was baked at 120°C for 5 minutes, then exposed to the whole substrate for 12 seconds, and then baked at 130°C for 30 minutes. The thickness of the polymer undercoat was 5 μm.

[0080] (3) Fabrication of the polymer waveguide core layer: The polymer waveguide core layer material EpoCore was spin-coated onto the polymer cladding layer to form a polymer film using a spin-coating process. The spin-coating speed was 3350 rpm, and the thickness of the polymer film was 9 μm. The polymer film was pre-baked using a stepped heating method, first at 50℃ for 10 minutes, then at 95℃ for 15 minutes, and then cooled after baking. The prepared polymer film was then subjected to photolithography. The ultraviolet light emitted by the photolithography machine had a wavelength of 365 nm, and the waveguide mask was the structure of the mode power divider to be prepared (e.g., Figure 2 As shown), photolithography is performed when the photomask is firmly attached to the silicon substrate, with two exposures, each lasting 3 seconds. This exposes the polymer waveguide core layer of the device's input / output region, directional coupling region, multimode interference region, and the tapered waveguide region connecting the multimode interference region and the input / output region to ultraviolet light. The photolithographically patterned silicon substrate is then removed from the photolithography machine and subjected to intermediate baking. First, it is baked at 50°C for 10 minutes, then at 85°C for 15 minutes. After baking, it is cooled to room temperature before proceeding to the next step. The polymer... The waveguide core structure is developed by first wet etching in Epo developer for 40 seconds to remove the unexposed non-polymer waveguide core structure, leaving only the polymer waveguide core structure corresponding to the mask. Then, isopropanol solution is used to wash away the developer and residual polymer waveguide core material on the silicon substrate surface. Subsequently, deionized water is used to rinse away the residual isopropanol on the surface and the surface is dried with nitrogen. Finally, post-baking is performed at 130°C for 40 minutes, thus completing the fabrication of the strip-shaped polymer waveguide core.

[0081] (4) Preparation of polymer cladding: EpoClad polymer cladding material was spin-coated onto the silicon substrate after the polymer waveguide core structure was prepared using a spin-coating process. The spin-coating speed was 4000 rpm. After spin-coating, the substrate was baked at 130°C for 5 minutes, exposed for 18 seconds, and then baked at 130°C for 30 minutes. The thickness of the polymer cladding on the waveguide core was 5 μm.

[0082] (5) Fabrication of the metal heating electrode: A 200 nm thick Al metal electrode film was deposited on the polymer overlay using a vacuum evaporation process. Then, positive photoresist BP 212 was spin-coated onto the Al metal electrode film at a rotation speed of 2500 rpm, resulting in a BP 212 film with a thickness of 2 µm. The device with the spin-coated BP 212 was heated to 87°C for 20 minutes, and then cooled to 25°C. A photomask was then used for alignment, with the mask having the same structure as the metal heating electrode to be fabricated (e.g., ...). Figure 2As shown, the device is exposed to ultraviolet light at a wavelength of 365 nm for 2 seconds to expose the photoresist BP 212 film in areas other than the metal heating electrode. The device is then immersed in a 5‰ NaOH solution for 20 seconds to remove the exposed photoresist BP 212 film, rinsed with deionized water, and dried with nitrogen. The device is then heated again at 95 °C for 10 minutes, followed by cooling to 25 °C. The Al metal heating electrode is then developed by immersing the device in a 5‰ NaOH solution for 5 minutes to remove the Al metal electrode film in areas other than the metal heating electrode. The device is then repeatedly rinsed with deionized water and dried with nitrogen. Finally, the device is immersed in ethanol for 5 seconds to remove the unexposed photoresist BP 212 film on the metal heating electrode, rinsed with deionized water, and dried with nitrogen, thus obtaining the tunable dual-mode six-port optical power divider described in this invention.

[0083] This results in the fabrication of a tunable dual-mode six-port optical power divider that meets the requirements. It should be noted that while this application contains descriptions of many details, they should not be construed as limiting the scope or potential claims of any disclosed technology, but rather as descriptions of features specific to particular embodiments that may be specific to the disclosed technology. The materials used in this design are not limited to these; waveguide materials such as lithium niobate, silicon, and silicon nitride can also be employed. Everything that is explicitly disclosed in this invention or unquestionably derived from the written description herein falls within the scope of protection of this application.

Claims

1. A tunable six-port optical power divider, characterized in that: From bottom to top, the structure consists of a silicon substrate (25), a polymer lower cladding layer (26) fabricated on the silicon substrate (25), a strip-shaped polymer waveguide core layer (27) fabricated on the polymer lower cladding layer (26), and a polymer upper cladding layer (28) fabricated on the polymer lower cladding layer (26) and the polymer waveguide core layer (27). The refractive index of the polymer waveguide core layer (27) is higher than that of the polymer lower cladding layer (26) and the polymer upper cladding layer (28). The polymer waveguide core layer (27) is based on MZI and MMI waveguide structures. From left to right along the direction of light propagation, it consists of an input few-mode straight waveguide (1), an input... Tapered waveguide (2), first S-bend waveguide (3) and second S-bend waveguide (4) with the same structure and size, first straight waveguide (5) and second straight waveguide (6) with the same structure and size and parallel to each other, third S-bend waveguide (7) and fourth S-bend waveguide (8) with the same structure and size, first coupled arm waveguide (9) and second coupled arm waveguide (10) with the same structure and size and parallel to each other, fifth S-bend waveguide (11) and sixth S-bend waveguide (12) with the same structure and size, first phase shifter straight waveguide (13) and second phase shifter straight waveguide (14) with the same structure and size and parallel to each other, first tapered waveguide (15) and... The second conical waveguide (16), the multimode interference waveguide (17), the third conical waveguide (29) and the eighth conical waveguide (34) of the same structure and size, the fourth conical waveguide (30) and the seventh conical waveguide (33) of the same structure and size, the fifth conical waveguide (31) and the sixth conical waveguide (32) of the same structure and size, the first output waveguide (18) and the sixth output waveguide (23) of the same structure and size, the second output waveguide (19) and the fifth output waveguide (22) of the same structure and size, and the third output waveguide (20) and the fourth output waveguide (21) of the same structure and size are aggregated on the second straight waveguide (6). A metal heating electrode (24) is fabricated on the cladding (28); the first S-bend waveguide (3), the first straight waveguide (5), the third S-bend waveguide (7), the first coupling arm waveguide (9), the fifth S-bend waveguide (11), the first phase shifter straight waveguide (13), and the first tapered waveguide (15) are connected in sequence and then connected to the multimode interference waveguide (17); the second S-bend waveguide (4), the second straight waveguide (6), the fourth S-bend waveguide (8), the second coupling arm waveguide (10), the sixth S-bend waveguide (12), the second phase shifter straight waveguide (14), and the second tapered waveguide (16) are connected in sequence and then connected to the multimode interference waveguide (17);The multimode interference waveguide (17) is connected to the first output waveguide (18), the sixth output waveguide (23), the second output waveguide (19), the fifth output waveguide (22), the third output waveguide (20), and the fourth output waveguide (21) via the third tapered waveguide (29), the eighth tapered waveguide (34), the fourth tapered waveguide (30), the seventh tapered waveguide (33), the fifth tapered waveguide (31), and the sixth tapered waveguide (32), respectively. The first output waveguide (18), the sixth output waveguide (23), the second output waveguide (19), the fifth output waveguide (22), the third output waveguide (20), and the fourth output waveguide (21) are connected to the first output waveguide (18), the sixth output waveguide (23), the second output waveguide (19), the fifth output waveguide (22), the third output waveguide (20), and the fourth output waveguide (21), respectively. 1) The six output terminals of the multimode interference waveguide (17) are formed; the signal light is input from the input few-mode straight waveguide (1), and after passing through the input tapered waveguide (2), it is divided into two signal lights that enter the first S-bend waveguide (3) and the second S-bend waveguide (4) respectively. Then, it enters the first coupling arm waveguide (9) and the second coupling arm waveguide (10) through the first straight waveguide (5) and the second straight waveguide (6), the third S-bend waveguide (7) and the fourth S-bend waveguide (8) respectively, and is coupled. Depending on the voltage applied to the metal electrode (24), the coupled signal light enters the fifth S-bend waveguide (11) and / or the sixth S-bend waveguide (12).

2. A tunable six-port optical power divider as described in claim 1, characterized in that: Input few-mode straight waveguide (1), first S-bend waveguide (3), second S-bend waveguide (4), first straight waveguide (5), second straight waveguide (6), third S-bend waveguide (7), fourth S-bend waveguide (8), first coupling arm waveguide (9), second coupling arm waveguide (10), fifth S-bend waveguide (11), sixth S-bend waveguide (12), first phase shifter straight waveguide (13), second phase shifter straight waveguide (14), input few-mode straight waveguide (15) The width of the connection between the input tapered waveguide (2), the connection between the first phase shifter straight waveguide (13) and the first tapered waveguide (15), the connection between the second phase shifter straight waveguide (14) and the second tapered waveguide (16), the output end of the first output waveguide (18), the output end of the sixth output waveguide (23), the output end of the second output waveguide (19), the output end of the fifth output waveguide (22), the output end of the third output waveguide (20), and the output end of the fourth output waveguide (21) The same, ranging from 3 to 11 μm; The length of the input few-mode straight waveguide (1) The width at the connection between the input tapered waveguide (2) and the first S-bend waveguide (3) and the second S-bend waveguide (4) is 500~3000μm. It is 6~15μm, and =2 ; length of the input tapered waveguide (2) The lengths are 400~1600μm; the lengths of the first S-bend waveguide (3) and the second S-bend waveguide (4), the first straight waveguide (5), the second straight waveguide (6), and the metal heating electrode (24) are 400~1600μm. and The lengths are equal to 800~2500μm; the lengths of the third S-bend waveguide (7) and the fourth S-bend waveguide (8) are also equal. The lengths of the fifth S-bend waveguide (11) and the sixth S-bend waveguide (12) The lengths are the same, ranging from 500 to 2200 μm; the lengths of the first coupling arm waveguide (9) and the second coupling arm waveguide (10) are also the same. Equal lengths, ranging from 200 to 1200 μm; the lengths of the first phase shifter straight waveguide (13) and the second phase shifter straight waveguide (14) are equal. Equal in width, ranging from 200 to 1400 μm; the width at the connection between the first tapered waveguide (15) and the second tapered waveguide (16) and the multimode interference waveguide (17) The lengths are the same, ranging from 5 to 15 μm; the lengths of the first tapered waveguide (15) and the second tapered waveguide (16) are also the same. Equal in width, ranging from 150 to 900 μm; the width of the multimode interference waveguide (17) The length is 40~120μm. The lengths of the first output waveguide (18), sixth output waveguide (23), second output waveguide (19), fifth output waveguide (22), third output waveguide (20), and fourth output waveguide (21) are 2500~4800μm. Equal in width, ranging from 800 to 2500 μm; the width of the metal heating electrode (24) The lengths of the third conical waveguide (29), the eighth conical waveguide (34), the fourth conical waveguide (30), the seventh conical waveguide (33), the fifth conical waveguide (31), and the sixth conical waveguide (32) are 4~12μm. Equal, ranging from 150 to 900 μm; the width at the connection between the third tapered waveguide (29), the eighth tapered waveguide (34), and the multimode interference waveguide (17) The same, ranging from 7 to 18 μm; Width at the connection between the fifth tapered waveguide (31), the sixth tapered waveguide (32) and the multimode interference waveguide (17) The same, 6~15μm; the width at the connection between the fourth tapered waveguide (30), the seventh tapered waveguide (33) and the multimode interference waveguide (17) The widths at the connections between the third tapered waveguide (29), the eighth tapered waveguide (34), the fourth tapered waveguide (30), the seventh tapered waveguide (33), the fifth tapered waveguide (31), the sixth tapered waveguide (32) and the first output waveguide (18), the sixth output waveguide (23), the second output waveguide (19), the fifth output waveguide (22), the third output waveguide (20), and the fourth output waveguide (21) are equal, and are... .

3. A tunable six-port optical power divider as described in claim 1, characterized in that: The thickness of the silicon substrate (25) is 0.5~1mm, the thickness of the polymer lower cladding (26) is 3~15μm, the thickness of the polymer waveguide core layer (27) is 4~13μm, the thickness of the polymer upper cladding (28) above the polymer waveguide core layer (27) is 3~15μm, and the thickness of the metal heating electrode (24) is 50~400 nm.

4. A tunable six-port optical power divider as described in claim 1, characterized in that: The polymer lower cladding (26) and polymer upper cladding (28) are made of one of the following materials: polycarbonate, polyimide, polymethyl methacrylate, polyethylene, polyester, polystyrene, and EpoClad; the polymer optical waveguide core layer (27) is made of one of the following materials: EpoCore, SU-8 2002, and SU-82005; and the metal heating electrode (24) is made of Al or Au.

5. A method for fabricating a tunable six-port optical power divider according to any one of claims 1 to 4, comprising the following steps: A: Cleaning of silicon wafer substrates Wipe the silicon substrate (25) vigorously with a cotton ball soaked in acetone, repeating 2-3 times. Then wipe the silicon substrate vigorously with a cotton ball soaked in ethanol, repeating 2-3 times. After wiping it clean, rinse it repeatedly with deionized water. Finally, blow the silicon substrate dry with nitrogen gas, then put it into a clean petri dish and seal it. B: Preparation of the polymer lower cladding layer The polymer undercoating material was spin-coated onto a clean silicon wafer substrate (25) using a spin-coating process. The spin-coating speed was 1000~5000 rpm. After spin-coating, the substrate was baked at 120~150℃ for 3~60 minutes. After baking with EpoClad material, the substrate was exposed for 5~60 seconds and then baked at 120~150℃ for 3~60 minutes to obtain the polymer undercoating (26). C: Fabrication of the polymer optical waveguide core layer Polymer waveguide core material was spin-coated onto the polymer cladding (26) to form a polymer waveguide core film (27'). The spin-coating speed was 1000~5000 rpm. The polymer waveguide core film (27') was then pre-baked at 50~180℃ for 3~30 minutes and allowed to cool naturally to room temperature. The polymer waveguide core film (27') was then subjected to photolithography. The ultraviolet light emitted by the photolithography machine had a wavelength of 350~400nm. The waveguide mask and the structure of the polymer waveguide core (27) to be prepared were complementary. Exposure was performed when the waveguide mask was in close contact with the silicon substrate. The exposure time was 4~40 seconds, so that the polymer waveguide core film (27') within the structure of the polymer waveguide core (27) to be prepared was exposed to ultraviolet light. The silicon wafer substrate after photolithography is removed from the photolithography machine and baked at 50~180℃ for 5~30 minutes. After baking, it is allowed to cool naturally to room temperature. The polymer waveguide core layer (27) structure is developed. First, wet etching is performed in the developer corresponding to the polymer waveguide core layer material for 15~80 seconds to remove the polymer waveguide core layer film (27') other than the unexposed polymer waveguide core layer (27) structure, leaving only the polymer waveguide core layer (27) structure corresponding to the waveguide mask. Then, the developer and the polymer waveguide core layer film (27') remaining on the surface of the silicon wafer substrate are washed away with isopropanol solution. Then, the surface is rinsed with deionized water to remove the residual isopropanol and dried with nitrogen. Finally, the substrate is baked at 120~150℃ for 30~60 minutes to perform post-baking hardening, thereby completing the preparation of the strip-shaped polymer waveguide core layer (27). D: Preparation of the polymer overcoat The polymer upper cladding material was spin-coated onto the polymer waveguide core layer (27) and the polymer lower cladding layer (26) using a spin-coating process. The spin-coating speed was 1000~5000 rpm. After spin-coating, the material was baked at 120~150℃ for 3~60 minutes to obtain the polymer upper cladding layer (28). E: Fabrication of the metal heating electrode 24 A metal electrode film (35) was deposited on the polymer overlay (28) using a vacuum evaporation process. Then, a positive photoresist BP 212 with a thickness of 1~3 µm was spin-coated onto the metal electrode film (35) at a rotation speed of 1000~3000 rpm. The device with the spin-coated photoresist BP 212 was heated at 70℃~100℃ for 10~30 minutes. After heating, the temperature was lowered to 20~30℃. Then, a photolithography was performed. The mask had the same structure as the metal heating electrode (24) to be prepared. The mask was exposed under ultraviolet light with a wavelength of 350~400 nm for 1~5 seconds, so that the photoresist BP 212 film in areas other than the metal heating electrode (24) was exposed. After exposure, the device is placed in a NaOH solution with a mass concentration of 2-5‰ for 10-60 seconds to remove the exposed photoresist BP 212 film. Then, it is rinsed with deionized water and dried with nitrogen. The device is heated again, that is, heated at 80~120 ℃ for 10~30 minutes. After heating, it is cooled to 20~30 ℃. Then the metal heating electrode (24) is developed. The device is placed in a NaOH solution with a mass concentration of 2~5‰ for 1~15 minutes to remove the electrode film in the area outside the metal heating electrode (24). The device is repeatedly rinsed with deionized water and dried with nitrogen. Finally, the device is placed in ethanol for 3~10 seconds to remove the unexposed photoresist BP 212 film on the metal heating electrode (24). The device is then rinsed with deionized water and dried with nitrogen to obtain a tunable dual-mode six-port optical power divider.

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