All-light-operated optical switch based on photoisomerism

Abstract

The invention discloses a full-light-operated optical switch based on photoisomerism, and belongs to the technical field of functional planar optical waveguide devices. The directional coupling optical device is a 2 * 2 device and is composed of a substrate layer, a buffer layer, a lower cladding layer, a core layer and an upper cladding layer from bottom to top, the core layer is composed of an input area, a directional coupling area and an output area in the optical transmission direction, and the input area is composed of a first straight waveguide, a first bent waveguide, a second straight waveguide and a second bent waveguide; the directional coupling area is composed of a fifth straight waveguide and a sixth straight waveguide, the output area is composed of a third bent waveguide, a third straight waveguide, a fourth bent waveguide and a fourth straight waveguide, extension lines of all the straight waveguides or extension lines of the straight waveguides are parallel to each other, and the input area and the output area are of symmetrical structures about the directional coupling area. Under the condition of external ultraviolet light, the refractive index of the core layer is changed, the coupling efficiency and the coupling length of light are changed, the function of the optical switch is achieved, the adjusted refractive index can be kept for a period of time, and therefore the optical switch has the memory characteristic.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional planar optical waveguide devices, and particularly relates to an all-optical controlled optical switch based on photo-isomerization. Background Art

[0002] With the rapid development of information technology and the increasing demand for high-speed and high-bandwidth communication, optical communication, as a high-speed, large-capacity, and low-power consumption communication method, has been widely applied. An optical switch is a device that realizes optical path switching by controlling the optical signal path and is widely used in fields such as optical communication, optical computing, and optical sensing. Optical switch technology is developing towards diversification with gradually improved performance. The main types include electro-optic switches, thermo-optic switches, mechanical optical switches, MEMS optical switches, etc. The materials of optical switches such as silicon, silicon nitride, indium phosphide, etc. have their own advantages and disadvantages. For example, silicon is easy to integrate but has a high power consumption due to the thermo-optical effect, while lithium niobate has a relatively fast electro-optical effect but a high driving voltage, and indium phosphide and lithium niobate still face technical challenges in integration. The current innovative ideas for optical switch technology mainly focus on simplifying its complex process, reducing the driving power consumption, and designing new modulation methods. Summary of the Invention

[0003] The object of the present invention is to solve the deficiencies of the existing optical switch technology, such as inconvenient regulation and control, high energy consumption, and lack of memory characteristics in optical power distribution, and propose an all-optical controlled optical switch based on photo-isomerization.

[0004] During the operation of the device of the present invention, under the irradiation of ultraviolet light, the molecular structure of the core layer material changes, the refractive index of the material increases, the coupling state in the modulation region changes, resulting in a change in the optical power distribution ratio. The material changes from colorless to blue, and this process is reversible. Under the action of infrared light or heat, the molecular structure of the material can be restored, the refractive index decreases, and the optical power distribution ratio of the device returns to the previous state, realizing the function of arbitrarily adjusting the splitting ratio. Due to the characteristics of the photo-isomerizable material, its molecular structure will not immediately recover after the external excitation is removed. Therefore, the adjusted refractive index will be maintained for a long time, thus having a memory function. The present invention selects a functional polymer material to prepare the optical switch, with a simple process. Its modulation method uses optical regulation, requires a relatively low modulation optical power, and the modulation has a memory characteristic. The optical switch described in the present invention is a tunable all-optical switch based on photo-isomerizable material with certain memory characteristics. Its advantage lies in the use of all-optical control adjustment, low power consumption, modulation with memory, and can be applied to all-optical networks. The present invention uses a photo-isomerizable material with bistability, which can maintain the switching state without continuous power supply after being excited by ultraviolet light, similar to the optical version of "non-volatile memory". The all-optical switch described in the present invention can be applied to all-optical signal routing and switching to achieve high-speed and low-power optical path dynamic reconstruction, and can also be applied to photonic computing and neural networks. Its all-optical control and synaptic characteristics can achieve the long-term retention of optical weights, and have great development potential in the future optoelectronic field.

[0005] The all-optical switch based on photo-isomerization described in the present invention is a 2×2 device. As shown in Figure 1 (a), from bottom to top, it is composed of a substrate layer 1, a buffer layer 2, a lower cladding layer 3, a core layer 4, and an upper cladding layer 5. The core layer 4 and the upper cladding layer 5 are both located above the lower cladding layer 3, and the core layer 4 is coated in the upper cladding layer 5; As shown in Figure 1 (b), along the optical transmission direction, the core layer 4 is composed of an input region 41, a directional coupling region 42, and an output region 43. The input region 41 is composed of a first straight waveguide 6, a first curved waveguide 7, a second straight waveguide 8, and a second curved waveguide 9. The directional coupling region 42 is composed of a fifth straight waveguide 10 and a sixth straight waveguide 11. The output region 43 is composed of a third curved waveguide 12, a third straight waveguide 13, a fourth curved waveguide 14, and a fourth straight waveguide 15. The first straight waveguide 6, the first curved waveguide 7, the fifth straight waveguide 10, the third curved waveguide 12, and the third straight waveguide 13 are connected in sequence. The second straight waveguide 8, the second curved waveguide 9, the sixth straight waveguide 11, the fourth curved waveguide 14, and the fourth straight waveguide 15 are connected in sequence; All straight waveguides or the extensions of straight waveguides are parallel to each other, and the input region 41 and the output region 43 are symmetric structures with respect to the directional coupling region 42.

[0006] Among them, all waveguide widths W1 are the same, ranging from 2 to 5 μm; the lengths L1 of the first straight waveguide 6, the second straight waveguide 8, the third straight waveguide 13, and the fourth straight waveguide 15 are the same, ranging from 600 to 1500 μm; the projected lengths L2 of the first curved waveguide 7, the second curved waveguide 9, the third curved waveguide 12, and the fourth curved waveguide 15 along the straight waveguide direction are the same, ranging from 200 to 800 μm; the lengths L3 of the fifth straight waveguide 10 and the sixth straight waveguide 11 are the same, ranging from 800 to 1200 μm, and the waveguide center spacing W2 between the fifth straight waveguide 10 and the sixth straight waveguide 11 is 3 to 5 μm; the waveguide center spacings W3 between the first straight waveguide 6 and the second straight waveguide 8, and between the third straight waveguide 13 and the fourth straight waveguide 15 are the same, ranging from 10 to 15 μm. The thickness of the substrate layer 1 is 300 to 800 μm, the thickness of the buffer layer 2 is 10 to 20 μm, the thickness of the lower cladding layer 3 is 2 to 10 μm, the thickness of the core layer 4 is 1 to 5 μm, and the thickness of the upper cladding layer 5 is 5 to 10 μm.

[0007] The attached drawing of the present invention Figure 1 The cross-sections at positions a and c described in Figure 1 (a) are shown in the attached drawing Figure 1 The cross-section at position b described in Figure 1 (a) is shown in the attached drawing Figure 1 From

[0008] It can be seen from (c) and (d) that the all-optical controlled optical switch based on photoisomerization described in the present invention is composed of a substrate layer 1, a buffer layer 2, a lower cladding layer 3, a core layer 4, and an upper cladding layer 5 from bottom to top.

[0009] The materials of the lower cladding layer 3 and the upper cladding layer 5 described in the present invention are a chlorine-containing electrolyte material PILs-Cl.

[0010] The material of the core layer 4 described in the present invention is a P(MMA-co-GMA) polymer material doped with bromoindolinospiropyran. The photochromic molecule bromoindolinospiropyran is doped in a polymethyl methacrylate-glycidyl methacrylate (P(MMA-co-GMA)) material, and the mass of bromoindolinospiropyran is 20 to 40% of the total mass of bromoindolinospiropyran and the P(MMA-co-GMA) polymer material.

[0011] The synthesis method of bromoindolinospiropyran (SP-Br) is as follows: First, dissolve 1,3,3-trimethyl-2-methyleneindole (1.8 mL, 10.57 mmol), 3,5-dibromosalicylaldehyde (2.8 g, 10.00 mmol) and triethylamine (1.5 mL, 10.7 mmol) in ethanol (30 mL), reflux for 6 h under nitrogen, cool overnight, filter out the solid, and wash with cold ethanol to obtain SP-Br. For the specific preparation method and experimental spectra, please refer to the reference (Ye Xiu, Wang, Anzhe, Zhang, Dongyang, Zhou, Peng, Zhu, Pengli. Light and pH dual-responsive spiropyran-based cellulose nanocrystals. RSC ADVANCES. Volume 13, 2023, ISSN 11495-11502). The structural formula of bromoindolinospiropyran at room temperature under visible light and the structural formula of the compound under ultraviolet light exposure are shown below:

[0012]

[0013] Figure 2 As shown, when the all-optical light switch based on photoisomerization of the present invention realizes the switching function, the power of the signal light is P in The signal light enters the directional coupling modulation region 42 by inputting through any one of the straight waveguides in the input region 41. Based on the evanescent field coupling effect of light waves, when light propagates in one waveguide, its field distribution will form an evanescent field around the waveguide; if the two waveguides are close enough, the evanescent field in one waveguide will interact with the light field in the other waveguide, resulting in the coupling and transmission of the optical signal between the two waveguides. By controlling the refractive index of the core waveguide to change the coupling efficiency and coupling length, the optical power of the signal light can be distributed between different waveguides in a specific proportion. Under the condition of externally applied ultraviolet light, the refractive index of the core layer changes. The change in the material refractive index will directly affect the propagation constant of light in the waveguide, and further affect the coupling coefficient between the waveguides, resulting in changes in the coupling efficiency and coupling length of light, adjusting the distribution ratio of the output optical power, and realizing the function of the optical switch. And due to the material characteristics, the change in the core material structure will not immediately recover when the excitation is withdrawn, and the adjusted refractive index can be maintained for a period of time. Therefore, the optical switch of the present invention has a memory characteristic, and this process is reversible. When externally applied infrared light or heating is applied, it will return to the original refractive index, and the optical power distribution ratio will return to the previous state.

[0014] The function of the photochromic material is as follows:

[0015] The photochromic material can keep the optical switch from recovering for a period of time after adjusting the optical power distribution of the two output waveguides. The photochemical reaction of the photochromic material not only causes a change in resistance but also leads to a change in the refractive index of the material. When the material absorbs light of a specific wavelength, the change in the molecular structure will cause a change in the electron cloud distribution and polarization characteristics of the material, thereby affecting the propagation speed of light in the material and resulting in a change in the refractive index. The metastable state formed by the photochromic material under light excitation has a certain stability, which is an important reason for its ability to maintain the refractive index. In the absence of external interference or sufficient energy excitation, the molecular structure of the metastable state will be maintained for a period of time, so that the refractive index also remains relatively stable.

[0016] The P(MMA-co-GMA) polymer material doped with bromoindolinospiropyran chromophore in the present invention is used to prepare the core layer 4 through spin coating, pre-baking, photolithography, development, and post-baking. And under infrared light or heating conditions, the material structure change is reversible, the refractive index decreases, the refractive index of the core layer changes, and thus the optical power ratio of the two output waveguides can be arbitrarily distributed. When the refractive index of the photochromic material increases, the optical field will be more concentrated inside the waveguide, resulting in a relatively reduced overlapping part of the optical fields between adjacent waveguides, thus causing the coupling coefficient to decrease. And the coupling length is inversely proportional to the coupling coefficient and is related to the phase velocity of light propagating in the waveguide. Since the change in refractive index will cause a change in the coupling coefficient, it will also affect the coupling length. When the increase in refractive index causes the coupling coefficient to decrease, according to the calculation formula of the coupling length, the coupling length will increase correspondingly, which means that light needs to travel a longer distance to complete the energy transfer from one waveguide to another. Therefore, after the external excitation light source changes the refractive index of the photochromic material, the power ratio of light in the two output waveguides will change.

[0017] The working process of the optical power distribution of the core layer 4 of the all-optical control optical switch based on photo-isomerization described in the present invention is as shown in the appendix Figure 3 As shown, the cis-trans isomerization of the used photochromic material is reversible. When the core layer 4 is irradiated with 360 nm ultraviolet light, the refractive index changes, resulting in a change in the coupling efficiency and coupling length, and a change in the optical power distribution ratio. Subsequently, when the device is placed under room temperature 605 nm visible light for 2 - 4 h, in a heating environment of 60 - 80 °C for 8 - 15 min, or under room temperature infrared light for 10 - 20 min, the refractive index of the core layer will gradually recover to the original refractive index with the irradiation or heating time, and the splitting ratio can also be adjusted in any proportion according to the length of the irradiation or heating time. Compared with the existing device structure and preparation technology, the beneficial effects of the present invention are:

[0018] (1) Compared with existing optical switches, the present invention can dynamically adjust the splitting ratio: The optical switch of the present invention utilizes the characteristics of photochromic materials and can conveniently adjust the refractive index of the core layer by selecting 360 nm ultraviolet light or 605 nm visible light, changing the coupling efficiency and coupling length, and thus adjusting the power distribution ratio in real time and dynamically. In contrast, the splitting ratio of traditional optical splitters is usually fixed or the adjustment process is relatively complex;

[0019] (2) Compared with existing optical switches, the present invention is easy to integrate. The all-optical controlled optical switch made of photochromic materials can be made very small in size, which is conducive to realizing the high integration of optical switches. In the fields of photon integration chips and the like, it can be closely integrated with other optical components and electronic components, reducing the volume and complexity of the system and improving the integration and performance density;

[0020] (3) Compared with existing optical switches, the present invention has low energy consumption. During the state switching process of the photochromic material, only 360 nm ultraviolet light or 605 nm visible light needs to be applied externally to change the refractive index of the core layer waveguide, thereby realizing the splitting function. Compared with some traditional optical switches, such as those based on mechanical movement or complex electromagnetic drive, the energy consumption is significantly reduced;

[0021] (4) Compared with existing optical switches, the present invention has the function of adjusting and maintaining the optical power distribution. In addition to the splitting function, the optical switch of the present invention also has a memory characteristic, which can change the splitting ratio at any time and remain for a period of time after the external excitation is removed, which is not possessed by traditional optical switches. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of an all-optical controlled optical switch based on photoisomerization according to the present invention; wherein Fig. (a) is a three-dimensional structural diagram of the all-optical controlled optical switch based on photoisomerization; Fig. (b) is a top view of the all-optical controlled optical switch based on photoisomerization; Fig. (c) is a cross-sectional schematic diagram at positions a and c in Fig. (a); Fig. (d) is a cross-sectional schematic diagram at position b in Fig. (a);

[0023] Figure 2 is a schematic diagram of the power distribution path of an all-optical controlled optical switch based on photoisomerization according to the present invention;

[0024] Figure 3 is a schematic diagram of the working process of an all-optical controlled optical switch based on photoisomerization for distributing optical power and reversibly regulating according to the present invention;

[0025] Figure 4 is a schematic diagram of the device structure of Embodiment 1 according to the present invention; Fig. (a) corresponds to the cross-sectional schematic diagram at positions a and c in the appendix Figure 1 in; Fig. (b) corresponds to the appendix Figure 1Schematic cross-sectional view at position b in the middle; Fig. (c) is a top view of the device in Example 1.

[0026] Figure 5 Curve graph showing the relationship between the refractive index of the core layer and the exposure time at a wavelength of 1310 nm in Example 1 of the present invention;

[0027] Figure 6 Simulation result graph of power distribution of the device in Example 1 of the present invention under different ultraviolet exposure durations of 0 s, 20 s, and 80 s;

[0028] Figure 7 Process flow chart for preparing the device in Example 1 of the present invention. Specific implementation manners

[0029] The present invention will be introduced more clearly and completely below in conjunction with the accompanying drawings. Those skilled in the art will have a deeper understanding of the advantages and functions of the present invention under this description. However, the described embodiments are part of the embodiments of the present invention, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] Example 1:

[0031] In this example, the selected substrate layer 1 is silicon with a thickness of 500 μm.

[0032] In this example, the selected buffer layer 2 is silicon dioxide with a thickness of 15 μm.

[0033] In this example, the lower cladding layer 3 and the upper cladding layer 5 used are a chlorine-containing electrolyte material PILs-Cl doped in a single solvent of methanol. For its preparation method and experimental spectra, please refer to the reference (Yunlong Yu, Zhiyan Ma, Xiaoya Miao, Yanyu Cui, Yaping Song, Sen Liu, Teng Fei, Tong Zhang. Humidity sensors based on cross-linked poly(ionic liquid)s for low humidity sensing. Sensors and Actuators B: Chemical. Volume 399, 2024, 134840, ISSN 0925-4005). After photopolymerization and volatilization of the methanol solvent, the lower cladding layer 3 and the upper cladding layer 5 with a thickness of 5 μm are obtained. The preparation reaction process of the chlorine-containing electrolyte material PILs-Cl doped in the methanol solvent is as follows:

[0034]

[0035] In this embodiment, the material used for the core layer 4 is a P(MMA-co-GMA) doping material containing bromoindolinospiropyran chromophore. The polymer material polymethyl methacrylate-glycidyl methacrylate used in this embodiment, its preparation method and structural characterization are detailed in the reference (Wang Wentong, Cao Chunlei, Qu Miao, etc. Influence of compatibilizer P(MMA-co-GMA) on the thermal stability and thermal oxidation stability of PA6 [J]. Polymer Materials Science and Engineering, 2014, 30(01): 7881+86. DOI: 10.16865 / j.cnki.10007555.2014.01.017.).

[0036] The synthesis process and molecular structure of polymethyl methacrylate-glycidyl methacrylate are as follows:

[0037]

[0038] In this embodiment, the mass of the bromoindolinospiropyran chromophore powder used in the core layer 4 material is 23% of the total mass of the bromoindolinospiropyran chromophore and bromo-P(MMA-co-GMA).

[0039] The basic synthesis method of the P(MMA-co-GMA) material doped with bromoindolinospiropyran chromophore used in this embodiment is as follows:

[0040] 1. Take 90 mg of bromoindolinospiropyran chromophore powder and place it in a clean weighing bottle, and then add 1 g of a cyclopentanone solution of P(MMA-co-GMA) with a solid content of 30%;

[0041] 2. Wrap the weighing bottle with tin foil and put it into an ultrasonic cleaner in the dark, and ultrasonically stir for 10 min to completely disperse the bromoindolinospiropyran chromophore powder evenly in the cyclopentanone solution of P(MMA-co-GMA) with a solid content of 30% to obtain a P(MMA-co-GMA) doping material containing bromoindolinospiropyran chromophore.

[0042] As attached Figure 4 And Figure 1As shown in (b), in this embodiment, all waveguide widths W1 are the same, which is 2 μm. The thicknesses of the lower cladding 3 and the upper cladding 5 are the same, which is 5 μm. The thickness of the core layer 4 is 3 μm. The lengths L1 of the first straight waveguide 6, the second straight waveguide 8, the third straight waveguide 13, and the fourth straight waveguide 15 are the same, which is 1000 μm. The lengths L2 of the first curved waveguide 7, the second curved waveguide 9, the third curved waveguide 12, and the fourth curved waveguide 15 are the same, which is 500 μm. The lengths L3 of the fifth straight waveguide 10 and the sixth straight waveguide 11 are the same, which is 1000 μm. The distance W2 between the fifth straight waveguide 10 and the sixth straight waveguide 11 is 4 μm. The waveguide center distances between the first straight waveguide 6 and the second straight waveguide 8, and between the third straight waveguide 13 and the fourth straight waveguide 15 are the same, which is 14.32 μm. The structural dimensions of the symmetric parts are the same.

[0043] In this embodiment, the wavelength of the signal light is selected as 1310 nm.

[0044] The initial refractive index of the core layer material used in this embodiment is 1.66 at a wavelength of 1310 nm.

[0045] In this embodiment, the Rsoft software is used to simulate the change of the output optical power of the device when the refractive index of the core layer material changes under different exposure times of 360 nm ultraviolet light. By measuring the refractive index of the core layer material, as shown in the appendix Figure 5 it can be seen that as the exposure time gradually increases, the refractive index of the waveguide core layer 4 at a wavelength of 1310 nm shows an upward trend. By simulating the relationship between the refractive index of the core layer of the device and the change of the output power distribution, as shown in the appendix Figure 6 it can be seen that as the refractive index of the core layer 4 increases, the coupling efficiency of the directional coupling region 42 decreases, and the coupling length increases, resulting in a change in the proportion of the output optical power. Figure 6 (a) is the initial state with an exposure duration of 0 s, corresponding to the Bar state of the optical switch. Figure 6 (b) is the state of 20 s of ultraviolet exposure, corresponding to the Cross state of the optical switch. Figure 6 (c) is the state of 80 s of ultraviolet exposure, corresponding to the 3-dB state of the optical switch. In summary, with the change of the refractive index of the core layer, the function of adjusting the proportion of the optical power distribution can be realized.

[0046] The preparation method of the all-optical controlled optical switch based on photoinduced isomerization fabricated in this embodiment is as shown in the appendix Figure 7 and is specifically described as follows:

[0047] A. Using single-crystalline silicon as the substrate layer 1 and the silicon dioxide layer existing on the substrate layer 1 as the substrate layer 2, first clean the surface of the silicon dioxide. Place the silicon wafer in a beaker containing acetone solution, take it out after ultrasonic cleaning in an ultrasonic machine for 10 minutes, then put it into a beaker containing isopropyl alcohol solution, take it out after ultrasonic cleaning in an ultrasonic machine for 10 minutes, then place it in a beaker containing deionized water, ultrasonic clean it in an ultrasonic machine for 10 minutes, take it out and use a nitrogen gun to blow dry the deionized water on the surface of the silicon wafer, and finally place the silicon wafer in a glassware and put it in an oven for drying (150 °C, 30 minutes) to remove surface moisture and organic impurities;

[0048] B. Spin-coat the chlorine-containing electrolyte material PILs-Cl doped in methanol single solvent (the mass percentage content of the chlorine-containing electrolyte material PILs-Cl is 25%, rotation speed 1000 r / min, time: 20 s) on the surface of the treated silicon dioxide layer. Immediately after spin-coating, expose it to ultraviolet light (365 nm, 0.12 J / cm 2 ) for 30 minutes for photocuring to volatilize the methanol solvent and obtain the chlorine-containing electrolyte material PILs-Cl lower cladding layer 3;

[0049] C. Spin-coat the P(MMA-co-GMA) material doped with bromoindolinospiropyran chromophore (rotation speed: 3000 r / min, time: 20 s) on the surface of the lower cladding layer 3. Immediately after spin-coating, perform thermal curing on a hot plate (pre-baking: 65 °C, 10 minutes; post-baking: 95 °C, 40 minutes) to obtain a 3-μm P(MMA-co-GMA) material core layer film 4' doped with bromoindolinospiropyran chromophore;

[0050] D. Use photolithography and wet etching processes to prepare the core layer structure of the device: After spin-coating the core layer film 4'; perform pre-baking on the obtained polymer optical waveguide core layer film 4', that is, use a stepwise heating method, first bake at 60 °C for 10 minutes, then bake at 90 °C for 20 minutes, and perform a cooling treatment after baking; perform alignment photolithography on the prepared polymer optical waveguide core layer film 4'. The wavelength of the ultraviolet light emitted by the photolithography machine is 365 nm. When the photomask 6 is tightly attached to the polymer optical waveguide core layer film 4', perform photolithography, and the exposure time is 14 s, so that the polymer optical waveguide core layer film 4' in the input / output area and directional coupling area of the device to be prepared is exposed to ultraviolet light; Take the device after photolithography off the photolithography machine and perform post-baking, first bake at 65 °C for 10 minutes, then bake at 95 °C for 20 minutes, and perform a cooling treatment after baking. After cooling to room temperature, perform the next operation;

[0051] E. Develop the polymer optical waveguide core layer film 4'. First, wet-etch it in the developer for 20 s to remove the unexposed non-polymer optical waveguide core layer structure, leaving only the polymer optical waveguide core layer structure corresponding to the mask. Then, wash the developer and the residual polymer optical waveguide core layer film on the silicon wafer surface with isopropyl alcohol solution. Subsequently, rinse the residual isopropyl alcohol on the surface with deionized water and dry it with nitrogen. Finally, perform post-baking to harden the film, bake it at 120 °C for 30 min, and thus complete the preparation of the polymer optical waveguide core 4.

[0052] F. Spin-coat the chlorine-containing electrolyte material PILs-Cl doped in methanol single solvent (the mass percentage content of the chlorine-containing electrolyte material PILs-Cl is 25%, rotation speed 1000 r / min, time: 20 s) on the core layer 4. Immediately after spin-coating, expose it to ultraviolet light (365 nm, 0.12 J / cm 2 ) for 30 min for photocuring to volatilize the methanol solvent, obtaining the chlorine-containing electrolyte material PILs-Cl upper cladding 5. Then, perform pre-baking at 90 °C for 20 min and cool it naturally to room temperature, thereby preparing an all-optical controlled optical switch based on photoisomerization.

[0053] For the all-optical controlled optical switch based on photoisomerization prepared in this example, when the prepared device is irradiated under the conditions of ultraviolet radiation with a radiation intensity of 25 mW / cm 2 for 20 s, 40 s, 60 s, and 80 s, the refractive index of the core layer changes from the original 1.65996@1310 nm to 1.67868@1310 nm, 1.6797@1310 nm, 1.68925@1310 nm, and 1.69333@1310 nm respectively. Placing it under room temperature visible light for 3 h, in a 70 °C heating environment for 10 min, or under outdoor infrared light for 15 min can restore the refractive index to the initial state; if it is necessary to adjust the optical switch power distribution again, irradiate it again.

Claims

1. An all-optical controlled optical switch based on photoisomerization, characterized in that: It is a 2×2 device, which is composed of a substrate layer (1), a buffer layer (2), a lower cladding layer (3), a core layer (4) and an upper cladding layer (5) from bottom to top. The core layer (4) and the upper cladding layer (5) are both located above the lower cladding layer (3), and the core layer (4) is covered by the upper cladding layer (5). Along the optical transmission direction, the core layer (4) consists of an input region (41), a directional coupling region (42) and an output region (43). The input region (41) is composed of a first straight waveguide (6), a first bent waveguide (7), a second straight waveguide (8) and a second bent waveguide (9). The directional coupling region (42) is composed of a fifth straight waveguide (10) and a sixth straight waveguide (11). The output region (43) is composed of a third bent waveguide (12), a third straight waveguide (13), a fourth bent waveguide (14) and a fourth straight waveguide (15). The first straight waveguide (6), the first bent waveguide (7), the fifth straight waveguide (10), the third bent waveguide (12) and the third straight waveguide (13) are connected in sequence. The second straight waveguide (8), the second bent waveguide (9), the sixth straight waveguide (11), the fourth bent waveguide (14) and the fourth straight waveguide (15) are connected in sequence. All the straight waveguides or the extension lines of the straight waveguides are parallel to each other. The input region (41) and the output region (43) are symmetric structures with respect to the directional coupling region (42).

2. The all-optical controlled optical switch based on photo-induced isomerization according to claim 1, characterized in that: The thickness of the substrate layer (1) is 300 - 800 μm, the thickness of the buffer layer (2) is 10 - 20 μm, the thickness of the lower cladding layer (3) is 2 - 10 μm, the thickness of the core layer (4) is 1 - 5 μm, and the thickness of the upper cladding layer (5) is 5 - 10 μm.

3. The all-optical controlled optical switch based on photoisomerization according to claim 1, wherein: The width W1 of all waveguides is the same, which is 2 - 5 μm. The lengths L1 of the first straight waveguide (6), the second straight waveguide (8), the third straight waveguide (13) and the fourth straight waveguide (15) are the same, which is 600 - 1500 μm. The projected lengths L2 of the first bent waveguide (7), the second bent waveguide (9), the third bent waveguide (12) and the fourth bent waveguide (15) along the straight waveguide direction are the same, which is 200 - 800 μm. The lengths L3 of the fifth straight waveguide (10) and the sixth straight waveguide (11) are the same, which is 800 - 1200 μm. The waveguide center distance W2 between the fifth straight waveguide (10) and the sixth straight waveguide (11) is 3 - 5 μm. The waveguide center distances W3 between the first straight waveguide (6) and the second straight waveguide (8), and between the third straight waveguide (13) and the fourth straight waveguide (15) are the same, which is 10 - 15 μm.

4. The all-optical controlled optical switch based on photoinduced isomerization according to claim 1, characterized in that: The materials of the substrate layer (1) and the buffer layer (2) are silicon and silicon dioxide respectively. The materials of the lower cladding layer (3) and the upper cladding layer (5) are electrolyte PILs-Cl materials containing chlorine. The material of the core layer (4) is a P(MMA-co-GMA) polymer material doped with bromoindolinospiropyran, where the mass of bromoindolinospiropyran is 20 - 40% of the total mass of bromoindolinospiropyran and the P(MMA-co-GMA) polymer material.

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