Visible light waveguide amplifier chip based on fluorescent polymer
The fluorescent polymer-based optical waveguide amplifier chip prepared by ultraviolet lithography direct writing process uses TS-FRET and SS-FRET mechanisms to solve the shortcomings of signal amplification in plastic optical fiber communication networks, realize efficient signal gain and simplified preparation processes, and improve communication capacity and efficiency.
Patent Information
- Application Number
- CN202510736783.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-09-02
AI Technical Summary
The existing plastic optical fiber communication networks face the problem of degradation of data quality at the reception side in long-distance and large-capacity transmission, and the existing optical waveguide amplifiers have shortcomings in gain performance and preparation processes.
The ultraviolet lithography direct writing process was used to prepare an optical waveguide amplifier chip based on fluorescent polymers. The triplet to singlet resonance energy transfer (TS-FRET) and singlet to singlet resonance energy transfer (SS-FRET) mechanisms were used to dopant green and red fluorescent small molecule oligomers as gain medium to achieve significant gain effect of signal light.
Achieving gains over a wide spectral range, improving communication capacity and efficiency, simplifying the preparation process, reducing costs, and adapting to different wavelengths and functional requirements.
Smart Images
Figure CN120577992A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polymer optical waveguide amplifiers, and in particular relates to an optical waveguide amplifier chip based on fluorescent polymer. Background Art
[0002] Plastic optical fiber (POF) systems have recently garnered widespread attention in areas such as short-distance communications, automotive electronics, and medical devices due to their unique performance and application scenarios. Plastic optical fiber, made from polymer materials such as polymethyl methacrylate (PMMA), boasts significantly lower raw material costs than quartz fiber. Its flexibility, bending resistance, and vibration resistance make it suitable for cabling in complex environments. Plastic optical fiber also boasts high bandwidth and low loss. Because it transmits optical signals rather than electrical signals, it is unaffected by electromagnetic radiation, lightning, radio frequency interference (RFI), or crosstalk from adjacent cables. However, its long-distance and high-capacity transmission capabilities are limited. With the surge in the number of users and devices in links, POF communication networks are facing the challenge of degraded data quality at the receiving end. Optical signal amplification has become increasingly important for improving the quality of service in communication networks. Polymer optical waveguide amplifiers, with their ease of integration, low cost, low power consumption, excellent gain performance, and high thermal stability, hold great research value for optical signal amplification. Summary of the Invention
[0003] The purpose of the present invention is to provide a fluorescent polymer-based optical waveguide amplifier chip (FDWA). The chip of the present invention is prepared using a UV direct writing process. The principle is to dope green and red fluorescent small molecule oligomers with high-efficiency photoluminescence properties into polymer materials as gain media, and utilize the triplet to singlet state conversion to generate a fluorescent waveguide amplifier chip. Resonance Energy Transfer (TS-FRET) and Singlet-to-Singlet The two energy transfer mechanisms of SS-FRET achieve a more significant gain effect of FDWA.
[0004] The fluorescent polymer-based optical waveguide amplifier chip (FDWA) of the present invention has a three-dimensional structure as shown in the attached figure. Figure 1 (a) shows the cross section at a. Figure 1 (b) As shown in the attached figure, the cross section at point b is as shown in the attached figure. Figure 1As shown in Figure (c), it is composed of a substrate layer 1, a buffer layer 2, a waveguide layer 3 and a cladding layer 4 from bottom to top. The waveguide layer 3 and the cladding layer 4 are located together on the buffer layer 2, and the waveguide layer 3 is clad in the cladding layer 4. Along the input direction of the signal light, the waveguide layer 3 is composed of an input end straight waveguide, an input end tapered waveguide, a straight waveguide, an output end tapered waveguide and an output end straight waveguide. The input end straight waveguide and the output end straight waveguide, as well as the input end tapered waveguide and the output end tapered waveguide are symmetrical structures with respect to the straight waveguide. The widths of the input end straight waveguide and the output end straight waveguide are greater than the width of the straight waveguide. The thicknesses of the waveguides in the waveguide layer 3 are the same.
[0005] The material of the substrate layer 1 of the present invention is one of indium phosphide, gallium arsenide, and silicon;
[0006] The material of the buffer layer 2 of the present invention is one of SU-8, PMMA, P(MMA-co-GMA), and silicon dioxide;
[0007] The waveguide layer 3 material described in the present invention is obtained by doping TCBzC and TCNzC fluorescent small molecule polymer chromophores and a photoinitiator into a polymer material. The polymer material is one of FSU-8 and P(MMA-co-GMA). The sum of the mass fractions of the TCBzC and TCNzC fluorescent small molecule polymer chromophores doped is 2 to 8 wt%, and the mass fraction of the photoinitiator doped is 1 to 5 wt%.
[0008] The material of the coating layer 4 of the present invention is one of SU-8, PMMA, P(MMA-co-GMA), and silicon dioxide. In the same device, the materials of the buffer layer 2 and the coating layer 4 can be the same or different.
[0009] All of the above materials are commercially available.
[0010] The structural formulas of TCBzC, TCNzC and the photoinitiator are shown in (a), (b) and (c), respectively.
[0011]
[0012] The working principle of the FDWA of the present invention is as shown in the attached figure. Figure 2 、 Figure 3 As shown. Figure 2 As shown, the signal light Iλ1 and the pump light B λ3 From the input end of waveguide layer 3, the pump light B λ3 Under the stimulation of Figure 3As shown in (a), the photoinitiator donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and then enters the triplet state (T1) through intersystem crossing (ISC). TS-FRET is carried out from the T1 energy level of the photoinitiator donor to the S1 energy level of the TCBzC acceptor. Through dipole-dipole coupling, the energy of the triplet state (T1) of the photoinitiator donor is transferred to the TCBzC acceptor in a non-radiative manner. The TCBzC acceptor is excited and emits a photon of signal light Iλ1 wavelength. At the same time, Figure 3 As shown in (b), the photoinitiator donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and then enters the triplet state (T1) through intersystem crossing (ISC). TS-FRET is performed from the T1 energy level of the photoinitiator donor to the S1 energy level of the TCNzC acceptor. Through dipole-dipole coupling, the energy of the triplet state (T1) of the photoinitiator donor is non-radiatively transferred to the TCNzC acceptor. The TCNzC acceptor is excited and emits a photon of signal light Iλ1 wavelength, successfully achieving effective gain enhancement through the sensitization process. At the same time, as shown in Figure 3 As shown in (c), under the pump light B λ3 Under the excitation of , the TCBzC donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and SS-FRET occurs from the S1 energy level of the TCBzC donor to the S1 energy level of the TCNzC acceptor. Through the dipole-dipole interaction, the energy of the TCBzC donor singlet state (S1) is transferred to the TCNzC acceptor in a non-radiative manner. The TCNzC acceptor is excited and emits a photon of signal light Iλ1 wavelength, and the final output signal light O λ1 The gain amplification of the input signal light Iλ1 is achieved.
[0013] Similarly, if Figure 2 As shown, the signal light Iλ2 and the pump light B λ3 From the input end of waveguide layer 3, the pump light B λ3 Under the excitation of , the output signal light O λ2 The gain amplification of the input signal light Iλ2 is successfully achieved.
[0014] The signal light Iλ1, Iλ2 and pump light B used in the FDWA chip of the present invention λ3 Both come from lasers. The wavelength range of signal light Iλ1 and Iλ2 is 500~700nm, and the power range is 0.2~200mW; the pump light B λ3 The wavelength range is 400-600nm, and the power range is 10-100mW.
[0015] Compared with existing device structures and preparation technologies, the present invention has the following beneficial effects:
[0016] (1) Compared with existing amplifier devices, the present invention can achieve gain in a wide spectral range and improve communication capacity and efficiency.
[0017] (2) Compared with existing amplifier devices, the polymer material of the present invention can be modified to adjust the refractive index to adapt to different wavelengths and functional requirements.
[0018] (3) Compared with existing amplifier devices, the device manufacturing process of the present invention is simple, and the devices can be mass-produced using an ultraviolet photolithography direct writing process, thereby improving production efficiency and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 (a) Schematic diagram of the three-dimensional structure of FDWA; Figure 1 (b) Figure 1 Schematic diagram of the cross section at position a in (a); Figure 1 (c) Figure 1 Schematic diagram of the cross section at position b in (a);
[0020] Figure 2 The working principle diagram of FDWA signal transmission;
[0021] Figure 3 (a) Schematic diagram of energy transfer between the photoinitiator donor and the TCBzC acceptor; Figure 3 (b) Schematic diagram of energy transfer between the photoinitiator donor and the TCNzC acceptor; Figure 3 (c) Schematic diagram of energy transfer between TCBzC donor and TCNzC acceptor;
[0022] Figure 4 (a) corresponds to the device of Example 1 Figure 1 Schematic diagram of the cross-sectional dimensions at position a in (a); Figure 4 (b) corresponds to the device of Example 1 Figure 1 Schematic diagram of the cross-sectional dimensions at position b in (a); Figure 4 (c) is a schematic diagram of the top view of the device of Example 1;
[0023] Figure 5 (a) is the signal light Iλ1 and the pump light B in Example 1 of the present invention. λ3 The relative gain curve of the waveguide layer 3 under the action of Figure 5 (b) is the difference between the signal light Iλ2 and the pump light B in Example 1 of the present invention. λ3 The relative gain curve of the waveguide layer 3 under the action of Figure 5 (c) is the case in Example 1 of the present invention where only the pump light B λ3 ASE spectrum generated by the waveguide layer 3 under action;
[0024] Figure 6 Flow chart of the preparation process of the device of the present invention. DETAILED DESCRIPTION
[0025] The present invention will be described more clearly and completely below with reference to the accompanying drawings. Those skilled in the art will have a deeper understanding of the advantages and functions of the present invention through this description. However, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.
[0026] Example 1
[0027] The substrate layer 1 selected in this embodiment is a silicon substrate with a thickness of 730 μm;
[0028] The buffer layer 2 selected in this embodiment is silicon dioxide with a thickness of 5 μm;
[0029] The material of the coating layer 4 selected in this embodiment is P (MMA-co-GMA);
[0030] In this embodiment, the fluorescent small molecule oligomer chromophores used in waveguide layer 3 are TCBzC and TCNzC. Their preparation and characterization are detailed in the reference (Zhang M, Xue SF, Dong WY, et al. Highly-efficient solution-processed OLEDs based on new bipolar emitters [J]. Chemical Communications, 2010, 46: 3923-3925). The polymer material used in waveguide layer 3 is FSU-8.
[0031] In the waveguide layer 3 of this embodiment, the mass fractions of the fluorescent small molecule oligomer chromophores TCBzC and TCNzC are 2.52 wt % and 2.48 wt %, respectively.
[0032] As attached Figure 4 As shown, the thickness of the waveguide layer 3 in this embodiment is 5 μm; the width of the straight waveguide at the input end and the straight waveguide at the output end is 10 μm, and the width of the straight waveguide is 7 μm; the width of the wide end of the tapered waveguide at the input end and the tapered waveguide at the output end is 10 μm, and the width of the narrow end is 7 μm; along the input direction of light, the tapered waveguide at the input end linearly narrows, and the tapered waveguide at the output end linearly widens; the thickness of the buffer layer 2 is 5 μm, and the thickness of the cladding layer 4 above the buffer layer 2 is 8 μm; the length of the straight waveguide at the input end and the straight waveguide at the output end is 2740 μm, the length of the tapered waveguide at the input end and the tapered waveguide at the output end is 1370 μm, and the length of the straight waveguide is 6165 μm.
[0033] The basic synthesis method of the FSU-8 core material doped with fluorescent small molecule oligomers used in this embodiment is as follows:
[0034] 1) 5 g of FSU-8 photoresist (containing a photoinitiator at 3 wt %) was placed in a clean weighing bottle, and 0.129 g of TCBzC and 0.127 g of TCNzC (2.52 wt % and 2.48 wt %, respectively) were added to obtain an FSU-8 solution.
[0035] 2) Wrap the weighing bottle in step 1) with tin foil and place it on a stirring table in the dark, and stir at 45° C. for 30 minutes to completely dissolve the fluorescent small molecule oligomer chromophore in the FSU-8 solution to obtain an FSU-8 core layer photoresist material doped with the fluorescent small molecule oligomer chromophore.
[0036] In this embodiment, pump light B is selected λ3 The wavelength is 405nm and the power is 10~80mW.
[0037] In this embodiment, the wavelengths of the signal lights Iλ1 and Iλ2 are selected to be 532 nm and 655 nm, and the powers are both 80 mW.
[0038] The buffer layer 2 described in this embodiment has a refractive index of 1.45 at wavelengths of 405 nm, 532 nm, and 655 nm; the cladding layer 4 has a refractive index of 1.48 at wavelengths of 405 nm, 532 nm, and 655 nm; and the waveguide layer 3 has a refractive index of 1.601 at a wavelength of 405 nm, a refractive index of 1.597 at a wavelength of 532 nm, and a refractive index of 1.587 at a wavelength of 655 nm.
[0039] Under the excitation of pump light Bλ3, a triplet-to-singlet transition occurs between the photoinitiator donor and the acceptor TCBzC. Resonance energy transfer. The photoinitiator donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and then enters the triplet state (T1) through intersystem crossing (ISC). TS-FRET is performed from the T1 energy level of the photoinitiator to the S1 energy level of the TCBzC fluorescent material. The triplet to singlet state also occurs between the photoinitiator donor and the acceptor TCNzC. Resonance energy transfer. The photoinitiator donor obtains energy transfer from the ground state to the lowest singlet state, and then enters the triplet state through intersystem crossing, and TS-FRET is performed from the T1 energy level of the photoinitiator to the S1 energy level of the TCNzC fluorescent material. Under the excitation of the pump light Bλ3, a singlet-to-singlet state reaction occurs between the donor TCBzC and the acceptor TCNzC. Resonant energy transfer. The donor TCBzC obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and then SS-FRET is performed from the S1 energy level of TCBzC to the S1 energy level of TCNzC, ultimately achieving an effective output gain effect for the input signal light. When the signal light Iλ1 and Iλ2 are respectively input into the waveguide layer 3 simultaneously with the pump light Bλ3, the relative gain curve is shown in the figure below. Figure 5 (a) and Figure 5 As shown in (b). Due to the energy transfer phenomenon between fluorescent materials, an ASE spectrum similar to a flat band is produced, as shown in Figure 5 As shown in (c), the upper flat-band spectrum bandwidth is about 48 nm and the full width at half maximum is about 77.28 nm.
[0040] The relative gain of the waveguide layer 3 is measured in this embodiment, and the calculation formula used is: Where P out is the optical power intensity of the output signal when no pump light is applied, is the optical power intensity of the output signal when pump light is applied. Figure 5 (a) and Figure 5 (b) It can be observed that the signal light I λ1 and I λ2 The relative gain of the pump light Bλ3 increases gradually with the increase of the optical power intensity.
[0041] The preparation method of FDWA prepared in this embodiment has the following steps: Figure 6 The specific description is as follows:
[0042] (a) Using single-crystal silicon as substrate layer 1 and a silicon dioxide layer on substrate layer 1 as buffer layer 2, the substrate layer was immersed in a beaker containing acetone solution and cleaned in an ultrasonic cleaner for 5 minutes before removal. The substrate layer was then placed in a beaker containing isopropyl alcohol (IPA) solution and ultrasonically cleaned for 5 minutes to remove the organic solvent. The substrate was then rinsed with deionized water, and the deionized water on the surface of the buffer layer 2 was blown dry with a nitrogen gun. The substrate was finally placed in a glass container and dried in an oven at 120°C for 30 minutes to remove surface moisture and organic impurities.
[0043] (b) FSU-8 doped with a fluorescent small molecule oligomer chromophore was spin-coated (rotation speed: 2000 rad / s, time: 20 s) on the surface of the buffer layer 2 and then immediately pre-baked on a hot plate (120°C, 10 min) to obtain a 5 μm thick coating 4a doped with the fluorescent small molecule oligomer.
[0044] (c) After cooling the device coated with coating 4a from 25°C to room temperature, it was exposed to UV light at a wavelength of 350-400 nm for 111 seconds using a photomask 5 (with a structure complementary to the fabricated waveguide layer structure). The exposed portion of the photomask 5 formed the waveguide layer 3 structure. After post-baking (120°C for 10 minutes), the epoxy groups in the FSU-8 cross-linked at the exposed locations, improving thermal stability.
[0045] (d) Immersing the waveguide chip obtained in step (c) in a photoresist developer (propylene glycol methyl ether acetate (PGMEA)) for 15 seconds to dissolve the polymer film region without epoxy crosslinking; then placing the waveguide chip on a hot plate and heating it at 120° C. for 10 minutes to obtain a waveguide layer 3 having a thickness of 5 μm;
[0046] (e) P(MMA-co-GMA) was spin-coated (rotation speed: 1000 rad / s, time: 30 s) as the cladding layer 4 of the waveguide layer 3. The device was then placed on a hot plate and heated at 60°C for 5 min, 90°C for 10 min, and 120°C for 15 min to obtain a cladding layer 4 with a thickness of 8 μm, thereby preparing the FDWA.
Claims
1. An optical waveguide amplifier chip based on fluorescent polymer, characterized by: From bottom to top, the waveguide layer (3) and the cladding layer (4) are sequentially composed of a substrate layer (1), a buffer layer (2), a waveguide layer (3) and a cladding layer (4); the waveguide layer (3) and the cladding layer (4) are located on the buffer layer (2), and the waveguide layer (3) is clad in the cladding layer (4); along the input direction of the signal light, the waveguide layer (3) is respectively composed of an input end straight waveguide, an input end tapered waveguide, a straight waveguide, an output end tapered waveguide and an output end straight waveguide; the input end straight waveguide and the output end straight waveguide, the input end tapered waveguide and the output end tapered waveguide are symmetrical structures with respect to the straight waveguide; the widths of the input end straight waveguide and the output end straight waveguide are greater than the width of the straight waveguide; and the thicknesses of the waveguides in the waveguide layer (3) are the same.
2. The fluorescent polymer-based optical waveguide amplifier chip according to claim 1, wherein: The material of the substrate layer (1) is one of indium phosphide, gallium arsenide, and silicon; the material of the buffer layer (2) is one of SU-8, PMMA, P(MMA-co-GMA), and silicon dioxide; the material of the waveguide layer (3) is obtained by doping TCBzC and TCNzC fluorescent small molecule oligomer chromophores and a photoinitiator into a polymer material, wherein the polymer material is one of FSU-8 and P(MMA-co-GMA), the sum of the mass fractions of the TCBzC and TCNzC fluorescent small molecule oligomer chromophores doped is 2-8wt%, the mass fraction of the photoinitiator doped is 1-5wt%, and the structural formulas of TCBzC, TCNzC, and the photoinitiator are shown in (a), (b), and (c), respectively.
3. The fluorescent polymer-based optical waveguide amplifier according to claim 1 or 2, characterized in that: The thickness of the waveguide layer (3) is 5 μm; the width of the straight waveguide at the input end and the straight waveguide at the output end is 10 μm, and the width of the straight waveguide is 7 μm; the width of the wide end of the tapered waveguide at the input end and the tapered waveguide at the output end is 10 μm, and the width of the narrow end is 7 μm; along the input direction of light, the tapered waveguide at the input end narrows linearly, and the tapered waveguide at the output end widens linearly; the thickness of the buffer layer (2) is 5 μm, and the thickness of the cladding layer (4) above the buffer layer (2) is 8 μm; the length of the straight waveguide at the input end and the straight waveguide at the output end is 2740 μm, the length of the tapered waveguide at the input end and the tapered waveguide at the output end is 1370 μm, and the length of the straight waveguide is 6165 μm.
4. The fluorescent polymer-based optical waveguide amplifier chip according to claim 1 or 2, characterized in that: Signal light Iλ1 and pump light B λ3 From the input end of the waveguide layer (3), the pump light B λ3 Under the excitation of , the photoinitiator donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and then enters the triplet state (T1) through intersystem crossing (ISC). TS-FRET is performed from the T1 energy level of the photoinitiator donor to the S1 energy level of the TCBzC acceptor. Through dipole-dipole coupling, the energy of the triplet state (T1) of the photoinitiator donor is transferred to the TCBzC acceptor in a non-radiative manner. The TCBzC acceptor is excited and emits a photon of signal light Iλ1 wavelength; the photoinitiator donor obtains the ground state (S0) and enters the lowest singlet state (S1). The energy of the photoinitiator donor triplet state (T1) is transferred from the T1 energy level of the photoinitiator donor to the S1 energy level of the TCNzC acceptor through TS-FRET. Through the dipole-dipole coupling effect, the energy of the photoinitiator donor triplet state (T1) is non-radiatively transferred to the TCNzC acceptor. The TCNzC acceptor is excited and emits a photon of signal light Iλ1 wavelength. The effective gain enhancement is successfully achieved through the sensitization process. Under the pump light B λ3 Under the excitation of , the TCBzC donor obtains energy transfer from the ground state (S0) to the lowest singlet state (S1), and SS-FRET occurs from the S1 energy level of the TCBzC donor to the S1 energy level of the TCNzC acceptor. Through the dipole-dipole interaction, the energy of the TCBzC donor singlet state (S1) is transferred to the TCNzC acceptor in a non-radiative manner. The TCNzC acceptor is excited and emits a photon of signal light Iλ1 wavelength, and the final output signal light O λ1 Achieves gain amplification of the input signal light Iλ1; Similarly, the signal light Iλ2 and the pump light B λ3 From the input end of the waveguide layer (3), the pump light B λ3 Under the excitation of , the output signal light O λ2 The gain amplification of the input signal light Iλ2 is successfully achieved.
5. The fluorescent polymer-based optical waveguide amplifier according to claim 4, wherein: The wavelength range of signal light Iλ1 and Iλ2 is 500~700nm, and the power range is 0.2~200mW; the pump light B λ3 The wavelength range is 400-600nm, and the power range is 10-100mW.
6. The fluorescent polymer-based optical waveguide amplifier according to claim 5, characterized in that: Pump light B λ3 The wavelength is 405nm, and the wavelengths of the signal lights Iλ1 and Iλ2 are 532nm and 655nm.