Non-contact fiber optic connector, coating process, manufacturing process

Abstract

The application discloses a kind of non-contact optical fiber connectors, coating process, preparation process, it is related to the preparation field of light guide element, its technical scheme main point is, including: S1.vacuum extraction and control coating temperature at 25 ℃60 ℃;S2.open ion source auxiliary, in the end face of ferrule sequentially depositing five tantalum pentoxide and silicon dioxide to form four layers of antireflection film, and control specific deposition rate and thickness distribution relationship;S3.waterproof film deposition.The application solves the problem that MT ferrule is not resistant to high temperature by low temperature combined with ion source auxiliary technology, and realizes dense deposition using particle kinetic energy;By differential rate control, avoid loose structure and reduce thermal damage;By specific film thickness and material alternation design, use silicon dioxide stress to balance five tantalum pentoxide stress, relieve the stress mismatch caused by the difference of thermal expansion coefficient between film layer and substrate, prevent film layer cracking, significantly improve the environmental reliability of connector.

Description

Technical Field

[0001] This invention relates to the field of optical fiber component fabrication, and particularly to a non-contact optical fiber connector, a coating process, and a fabrication process. Background Technology

[0002] As optical communication technology evolves towards higher speeds and larger capacities, multi-core fiber optic connectors such as MT and MPO are increasingly used in data centers and optical modules. To effectively reduce insertion loss and eliminate return interference in optical links, the industry typically needs to fabricate high-performance anti-reflection coatings on the ferrule end faces of connectors. These anti-reflection optical films are fabricated using electron beam evaporation, which involves alternately depositing high-refractive-index tantalum pentoxide and low-refractive-index silicon dioxide to build the film system.

[0003] In traditional optical coating processes, to ensure sufficient density and adhesion of the oxide film, the substrate typically needs to be heated to a high temperature, such as 150°C or even higher. However, MT ferrule assemblies differ from conventional optical glass substrates; they are composites tightly assembled from quartz optical fibers, thermosetting epoxy resin adhesives, and polyphenylene sulfide plastic shells. These composite assemblies exhibit high temperature sensitivity. Directly applying conventional high-temperature coating processes can easily lead to adhesive aging and failure, ferrule deformation, or minute displacements and protrusions at the fiber end faces due to differences in thermal expansion of the components, ultimately resulting in product failure.

[0004] To avoid the aforementioned thermal damage, actual production often necessitates limiting the coating temperature. However, under conventional low-temperature conditions, the molecular mobility of deposited tantalum pentoxide and silicon dioxide is low, resulting in a loose microstructure and insufficient aggregation density in the film. When facing the stringent reliability standards of the optical communication industry, such as boiling water tests or high-low temperature cycling tests, these films are highly susceptible to peeling and detachment due to moisture absorption, stress release, or insufficient adhesion. Furthermore, since the ferrule end face comprises three materials with vastly different coefficients of thermal expansion—glass, organic adhesive, and plastic—improper process control during low-temperature deposition can easily lead to film cracking due to stress mismatch between the film and the substrate. Summary of the Invention

[0005] The purpose of this invention is to provide a coating process for non-contact fiber optic connectors. By using a low-temperature ion-assisted process, the problem of MT ferrules being intolerant to high temperatures and prone to loosening is solved. By utilizing a specific film thickness distribution to achieve stress matching to prevent cracking, a long-lasting and reliable coating with extremely low reflectivity, high density, and excellent hydrophobic protection is achieved while ensuring the physical precision of the connector.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A coating process for a non-contact fiber optic connector includes the following steps: S1: Place the coating tray containing the MT insert in a vacuum chamber for vacuum treatment to achieve the preset vacuum level and control the coating temperature to 25℃-60℃. S2: While maintaining the coating temperature, an ion source is turned on for assistance, and a first tantalum pentoxide film, a second silicon dioxide film, a third tantalum pentoxide film, and a fourth silicon dioxide film are sequentially deposited on the MT ferrule end face to form an antireflection film; wherein, in step S2, the deposition rate of tantalum pentoxide is controlled to be 2.0-3.0 Å / s, and the deposition rate of silicon dioxide is 3.5-4.5 Å / s; the first tantalum pentoxide film and the second silicon dioxide film form an inner film layer pair, and the third tantalum pentoxide film and the fourth silicon dioxide film form an outer film layer pair; the thickness of the antireflection film satisfies the following relationship: in both the inner and outer film layer pairs, the thickness of the silicon dioxide film is greater than the thickness of the tantalum pentoxide film; the thicknesses of the tantalum pentoxide film and the silicon dioxide film in the outer film layer pair are greater than the thicknesses of the tantalum pentoxide film and the silicon dioxide film in the inner film layer pair, respectively; S3: Turn off the ion source and deposit a waterproof membrane on the surface of the antireflective membrane.

[0007] Further settings: In step S1, the preset standard is a vacuum degree of 1.0 × 10⁻⁶ or better. -3 Pa; During the deposition process in step S2, the atmospheric pressure environment in the vacuum chamber is an oxygen-rich environment; High-purity oxygen is introduced into the vacuum chamber through a mass flow meter to maintain the working vacuum at a preset standard. Oxygen is used as a reaction gas to compensate for the oxygen vacancies generated by tantalum pentoxide and silicon dioxide during electron beam evaporation, so as to reduce the absorption rate of the antireflection film in the 1260nm-1650nm band.

[0008] Further settings: In step S2, the physical thickness range of each layer of the antireflective coating is as follows: The thickness of the first tantalum pentoxide film is 60nm-64nm; The thickness of the second silicon dioxide film is 73nm-77nm; The thickness of the third tantalum pentoxide film is 186nm-190nm; The thickness of the fourth silicon dioxide film is 243nm-247nm.

[0009] Further settings: In step S2, when using an electron gun for electron beam evaporation to deposit tantalum pentoxide and silicon dioxide films, the process parameters of the electron gun are controlled as follows: During the evaporation of tantalum pentoxide film, the electron gun current was controlled at 420mA±30mA; During the evaporation of the silicon dioxide film, the electron gun current is controlled at 220mA±30mA.

[0010] Further settings: In step S3, the deposition process of the waterproof membrane meets the following conditions: Deposition is performed using resistance evaporation; The deposition current was controlled at 425mA±30mA; The deposition rate was controlled at 12.0 Å / s ± 1.0 Å / s; The deposition thickness is 10nm-13nm.

[0011] Further settings: In step S2, the specific parameters for ion source assistance are controlled as follows: The ion source energy current is controlled at 900mA±100mA; The neutralizer bias current is controlled at 1350mA±100mA.

[0012] Further settings: During the deposition process in steps S2 and S3, the rotation speed of the coating disk is 30 rpm.

[0013] Further settings: In steps S2 and S3, a quartz crystal oscillator is used to monitor the deposition rate in real time at a sampling frequency of not less than 10 Hz; when the deviation of the monitored deposition rate from the target set value exceeds ±0.1 Å / s, the feedback system automatically adjusts the beam intensity of the electron gun or the heating power of the resistive evaporation source to correct the rate deviation back to the preset range within 0.5 seconds.

[0014] Another object of the present invention is to provide a manufacturing process for a non-contact fiber optic connector, comprising the following steps performed sequentially: SP1: Upper clamp; Install the MT core to be coated onto the coating tray, and ensure that the end faces of all cores are at the same height and the windows face the same direction; SP2: Cleaning; Place the clamped coated disc into an ultrasonic cleaner for cleaning to remove oil and particles from the end face; SP3: End face inspection; Perform microscopic inspection on the cleaned MT ferrule to confirm that there are no residual water stains or dirt on the end face; SP4: Install the coating tray that has passed inspection onto the rotating umbrella frame of the coating machine; SP5: Coating; Using the above coating process, antireflective and waterproof coatings are deposited on the end face of the MT ferrule; SP6: Lower the umbrella; after deposition is complete, remove the coating tray from the rotating umbrella frame; SP7: Lower clamp; Place the coating tray in a natural environment to cool for at least 10 minutes. After the temperature drops, remove the MT ferrule from the coating tray. SP8: Spectrophotometry; Use a spectrophotometer to test the reflectivity of the substrate coated in the same furnace to verify whether it meets the requirements in the 1260nm-1650nm wavelength band. SP9: Internal testing; Verification of sampled products, including placing the product in boiling water at 100°C for 15 minutes and then taking it out, and using 3M tape to perform an adhesion pull test to confirm that the film layer does not peel off. SP10: Visual inspection; Perform an end-face visual inspection on the final product to confirm that the film surface is free of scratches, pits and defects.

[0015] Another object of the present invention is to provide a non-contact fiber optic connector, which is manufactured using the coating process described above; Alternatively, it can be prepared using the above-described preparation process.

[0016] In summary, the present invention has the following beneficial effects: First, this invention solves the problem that the MT ferrule cannot withstand high-temperature coating due to its material properties by controlling the coating temperature to 25°C to 60°C in step S1 and activating the ion source for assistance in step S2. By utilizing the particle kinetic energy generated by the ion source to replace the thermal energy in the traditional process, the deposited molecules obtain sufficient migration energy on the low-temperature substrate surface and form a dense microstructure. Thus, while ensuring that the epoxy resin adhesive in the MT ferrule does not fail and the optical fiber does not shift, the dense deposition of tantalum pentoxide and silicon dioxide films is achieved.

[0017] This invention controls the deposition rate of tantalum pentoxide to 2.0 to 3.0 angstroms per second in step S2, and with the assistance of an ion source, provides sufficient time for the deposition and rearrangement of tantalum pentoxide molecules, thus avoiding the formation of a loose columnar structure under low-temperature conditions. At the same time, it controls the deposition rate of silicon dioxide to 3.5 to 4.5 angstroms per second, which shortens the duration of the entire coating process while ensuring the quality of the film formation. This reduces the total bombardment time of the ion source on the MT ferrule end face and prevents heat accumulation damage to the substrate caused by prolonged ion bombardment.

[0018] The invention defines an inner film pair consisting of a first tantalum pentoxide film and a second silicon dioxide film, and an outer film pair consisting of a third tantalum pentoxide film and a fourth silicon dioxide film, with the thickness of the silicon dioxide film being greater than that of the tantalum pentoxide film, thus forming a specific stress-matching structure. The tensile stress generated during silicon dioxide film deposition effectively balances the compressive stress generated by the tantalum pentoxide film. Combined with the distribution of the outer film pair's thickness being greater than that of the inner film pair, this effectively alleviates the stress mismatch caused by the difference in thermal expansion coefficients between the hard oxide antireflective coating and the flexible MT ferrule substrate, preventing the film layers from cracking during environmental testing.

[0019] In step S3 of this invention, the ion source is turned off, and a waterproof membrane is deposited on the surface of the antireflection membrane. By stopping the ion source assistance during the deposition of the waterproof material, the high-energy ion beam is prevented from breaking the organic molecular chains of the waterproof material, ensuring the integrity of the hydrophobic groups on the surface of the waterproof membrane. This results in a non-contact fiber optic connector with excellent anti-fouling performance and environmental reliability.

[0020] Second, in step S1, the present invention sets a preset vacuum standard to be 1.0 × 10⁻⁶ or better. -3 Pa, and in step S2, high-purity oxygen is introduced into the vacuum chamber using a mass flow meter to create an oxygen-rich environment, solving the technical problem of easy decomposition and oxygen loss of oxide materials in the electron beam evaporation process. By using the introduced oxygen as a reactant gas to carry out reactive evaporation, real-time oxygen composition compensation is performed on tantalum pentoxide and silicon dioxide molecules during the deposition process, effectively repairing lattice defects and suboxide absorption centers caused by oxygen vacancies, thereby restoring the deposited film to the standard stoichiometry, significantly reducing the optical absorption rate of the antireflection film in the 1260nm to 1650nm communication band, and minimizing the transmission loss of optical signals.

[0021] Third, each layer of the antireflective coating of this invention has a specific physical thickness, forming an optical film optimized for a wide band from 1260nm to 1650nm. By utilizing the multi-beam interference principle generated by the alternating stacking of high and low refractive index materials, efficient destructive interference is achieved in a wide spectral range, thereby ensuring that the non-contact fiber optic connector has extremely low reflectivity characteristics in the entire communication band covering the O-band to L-band.

[0022] Fourth, this invention precisely controls the electron gun current during the evaporation of tantalum pentoxide within a high-energy range of 420mA±30mA, providing a matching electron beam energy density to the high melting point and refractory physical properties of tantalum pentoxide. This ensures the stability of the molten pool of the evaporated material in the crucible while maintaining a low deposition rate of 2.0 to 3.0 Å per second, effectively preventing pulsation or interruption of the evaporation beam due to insufficient electron beam energy. Simultaneously, by controlling the electron gun current during the evaporation of silicon dioxide within a low-energy range of 220mA±30mA, the bombardment power of the electron beam is limited due to the poor thermal conductivity and easy sublimation of silicon dioxide. This effectively avoids material tunneling effects and macroscopic particle sputtering caused by local overheating. Thus, while achieving a high deposition rate of 3.5 to 4.5 Å per second, this invention ensures that the final antireflective film surface is free of pits and defects, improving the optical purity and surface smoothness of the film.

[0023] Fifth, this invention solves the technical problem of molecular bond breakage and decomposition failure of organic waterproof materials under high-energy particle bombardment by using resistance evaporation instead of electron beam evaporation and precisely controlling the deposition current to 425mA±30mA and the deposition rate to 12.0 Å per second. By utilizing the gentle thermal radiation energy provided by resistance heating, combined with a rapid deposition rate of 12.0 Å per second, the waterproof material can sublimate and adhere to the substrate in a short time. This effectively preserves the integrity of the hydrophobic functional groups of the organic fluoride while avoiding prolonged thermal decomposition. Combined with ultra-thin thickness control of 10nm to 13nm, the invention maximizes the hydrophobic angle and minimizes the coefficient of friction on the film surface without changing the original optical properties of the antireflective film, significantly improving the dirt resistance and easy cleaning performance of non-contact fiber optic connectors.

[0024] Sixth, this invention solves the technical problem of insufficient kinetic energy of deposited particles leading to porous films under low-temperature conditions by precisely controlling the ion source energy current within the mid-to-high energy range of 900mA±100mA. This parameter setting provides the deposited molecules with appropriate ion bombardment momentum, enabling them to achieve sufficient horizontal migration on the substrate surface to fill microscopic voids. Thus, without generating excessive heat that could cause the MT ferrule adhesive to fail, the physical densification and high refractive index characteristics of the oxide film are achieved.

[0025] Meanwhile, this invention employs a supersaturated electron neutralization strategy for insulating substrates such as PPS plastics and epoxy resins by setting the neutralizer bias current to a level significantly higher than the energy current of 1350mA±100mA. By providing a sufficient electron flow to neutralize the positive charge continuously accumulating on the deposition surface, the electrostatic field accumulation effect on the insulating substrate surface is effectively eliminated. This prevents a decrease in ion-assisted efficiency or abnormal discharge arcing caused by surface charge repulsion, ensuring that the ion beam can continuously and stably act on the substrate surface, thereby guaranteeing the adhesion and uniformity of the film layer on complex insulating substrates.

[0026] Seventh, this invention implements a key thermal stress release control strategy in step SP7. By forcing the coating pad to cool naturally in an environment for at least 10 minutes after exiting the furnace, the MT ferrule substrate containing heat-sensitive epoxy resin and plastic and the hard oxide film layer can be simultaneously and slowly cooled after experiencing a vacuum thermal environment. This delayed clamping process effectively avoids instantaneous thermal shock caused by the large difference in thermal expansion coefficients between the substrate and the film layer, preventing microcracks or crazing of the brittle film layer during rapid cooling and shrinkage, and significantly improving the final yield of composite substrate coated products. Attached Figure Description

[0027] Figure 1 This is a manufacturing process diagram for a non-contact fiber optic connector; Figure 2This is a schematic diagram of the coating process. Figure 3 It is a 3D topographic image of the interferometric measurement data; Figure 4 It is a graph of spectral performance test results. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] This invention provides a fabrication process for a non-contact fiber optic connector, comprising a complete fabrication process SP1-SP10. Step SP5 includes coating steps S1 to S3.

[0030] I. Overall Preparation Process; Step SP1: Upper clamp.

[0031] A coating tray is provided, which has mounting slots for fixing. The MT ferrules to be coated are installed sequentially into the mounting slots of the coating tray. The positions of each MT ferrule in the mounting slots are adjusted so that the end faces of all MT ferrules are at the same horizontal level and the optical windows of all MT ferrules face the same direction.

[0032] Step SP2: Cleaning.

[0033] An ultrasonic cleaner is provided, which contains cleaning fluid. The entire coated plate containing the MT ferrule is immersed in the cleaning fluid of the ultrasonic cleaner, and the ultrasonic generator is turned on to vibrate and clean the end face of the MT ferrule and the coated plate.

[0034] Step SP3: End face inspection.

[0035] After cleaning, the coated trays are removed from the ultrasonic cleaner and transferred to a microscopic inspection table. The end faces of the MT ferrules on the coated trays are scanned one by one using a microscope to confirm that the end faces are free of water stains and dirt.

[0036] Step SP4: Put on the umbrella.

[0037] A vacuum coating machine is provided, with a rotating umbrella frame installed inside the vacuum chamber. The qualified coating tray is transported into the vacuum chamber and fixedly mounted on the rotating umbrella frame, with the coating-to-be-coated end face of the MT insert facing the evaporation source below the vacuum chamber.

[0038] Step SP5: Coating.

[0039] With the vacuum chamber door closed, following the core coating process (S1-S3) described below, an antireflective coating and a waterproof coating are sequentially deposited on the end face of the MT ferrule during the revolution and rotation driven by the rotating umbrella frame. During this process, the coating disk rotation speed is set to 30 rpm.

[0040] Step SP6: Descend the umbrella.

[0041] After the coating process is completed and the pressure is restored to normal, open the vacuum chamber door and remove the coating disc from the rotating umbrella frame.

[0042] Step SP7: Lower clamp.

[0043] Place the removed coating tray in a natural cooling zone for at least 10 minutes to cool down. Once the coating tray has cooled, remove the MT insert from the mounting slot of the coating tray.

[0044] Step SP8: Spectroscopic detection.

[0045] Remove the do-coated sheet that was coated in the same furnace as the MT ferrule, place the do-coated sheet in the test optical path of the spectrophotometer, and detect its reflectance spectral data in the 1260nm to 1650nm communication band.

[0046] Step SP9: Internal loop test.

[0047] Samples were extracted from the MT ferrule after clamping for reliability verification. The boiling test conditions were as follows: the sampled product was placed in boiling water at 100℃ for 15 minutes, then removed and dried. The adhesion test conditions were as follows: 3M brand test tape was applied to the film surface and pulled to check the film's bonding performance.

[0048] Step SP10: Visual inspection.

[0049] The finished non-contact fiber optic connectors are subjected to end-face appearance inspection, and microscopic equipment is used to observe whether there are scratches, pits and damage defects on the film surface.

[0050] II. The coating process is a specific elaboration of step SP5; The vacuum deposition equipment used includes a closed-loop film thickness monitoring system, which consists of a quartz crystal oscillator located above the vacuum chamber and a feedback control unit located outside the vacuum chamber. During the deposition process, the quartz crystal oscillator monitors the deposition rate in real time at a sampling frequency of not less than 10 Hz; when the absolute value of the deviation between the monitored rate and the set value exceeds 0.1 Å / s, the feedback control unit issues a command within 0.5 seconds to adjust the electron gun beam current or the power of the resistive evaporation source.

[0051] The specific coating steps are as follows: Step S1.

[0052] Activate the exhaust system connected to the vacuum chamber, place the coating disk containing the MT ferrule inside the vacuum chamber, and evacuate until the vacuum level reaches the preset standard, specifically 1.0 × 10⁻⁶. -3Pa. Simultaneously turn on the heating and baking device to control the temperature of the base (MT insert) between 25°C and 60°C.

[0053] Step S2.

[0054] While maintaining the above-mentioned coating temperature, an ion source is turned on for auxiliary coating. High-purity oxygen is introduced into the vacuum chamber through a mass flow meter to establish an oxygen-rich environment, which is used to compensate for the oxygen deficiency caused by the evaporation of oxides.

[0055] With the aid of ion source bombardment, a first tantalum pentoxide film, a second silicon dioxide film, a third tantalum pentoxide film, and a fourth silicon dioxide film are sequentially deposited from the inside out on the end face of the MT ferrule to form an antireflection film. During this process, the deposition rate of tantalum pentoxide is strictly controlled at 2.0-3.0 Å / s, and the deposition rate of silicon dioxide is 3.5-4.5 Å / s. The physical thickness of the antireflection film satisfies the following relationship: the first tantalum pentoxide film and the second silicon dioxide film form an inner layer pair, and the third tantalum pentoxide film and the fourth silicon dioxide film form an outer layer pair; in both the inner and outer layer pairs, the thickness of the low-refractive-index silicon dioxide film is greater than the thickness of the high-refractive-index tantalum pentoxide film within the same group; simultaneously, the thickness of the tantalum pentoxide film in the outer layer pair is greater than the thickness of the tantalum pentoxide film in the inner layer pair, and the thickness of the silicon dioxide film in the outer layer pair is also greater than the thickness of the silicon dioxide film in the inner layer pair.

[0056] Step S3.

[0057] After the antireflection membrane deposition is complete, the ion source is turned off to stop the ion-assisted effect. The process is then switched to a resistance evaporation source to deposit another waterproof membrane on the surface of the antireflection membrane (i.e., the surface of the fourth silica layer). In step S3, a vacuum environment is maintained, and the waterproof material is heated to an evaporation state. The heating current of the resistance evaporation source is strictly controlled between 425 mA ± 30 mA, and the deposition rate is monitored using a quartz crystal oscillator, keeping it within the range of 12.0 Å / s ± 1.0 Å / s. By controlling the opening time of the baffle, the physical thickness of the waterproof membrane is precisely controlled between 10 nm and 13 nm to form a dense hydrophobic functional layer.

[0058] III. Specific Implementation Data; Example 1: This example uses the center value of a preset process parameter range for preparation.

[0059] In step S2, tantalum pentoxide and silicon dioxide are alternately evaporated using an electron beam evaporation source, with ion source assistance for deposition. The physical thickness of each film layer is precisely controlled using a film thickness monitoring device as follows: the first tantalum pentoxide film is 62 nm, the second silicon dioxide film is 75 nm, the third tantalum pentoxide film is 188 nm, and the fourth silicon dioxide film is 245 nm.

[0060] During this process, the operating parameters of the electron gun were set as follows: the emission current was controlled at 420mA when evaporating tantalum pentoxide, and the emission current was controlled at 220mA when evaporating silicon dioxide. Simultaneously, the auxiliary parameters of the ion source were set as follows: energy current 900mA, and neutralizer bias current 1350mA.

[0061] In step S3, the system is switched to resistance evaporation mode. The heating current of the resistance evaporation source is controlled at 425 mA, the deposition rate is stabilized at 12.0 Å / s, and the final physical thickness of the deposited waterproof film is 11.5 nm.

[0062] Example 2 differs from Example 1 only in that the process parameters are set to the lower limit of a preset range.

[0063] In step S2, the physical thickness of each film layer is adjusted as follows: the first tantalum pentoxide film is 60 nm, the second silicon dioxide film is 73 nm, the third tantalum pentoxide film is 186 nm, and the fourth silicon dioxide film is 243 nm.

[0064] The corresponding electron gun and ion source parameters are set as follows: the electron gun current is 390mA when evaporating tantalum pentoxide and 190mA when evaporating silicon dioxide; the energy current of the ion source is 800mA and the neutralizer bias current is 1250mA.

[0065] In step S3, the heating current of the resistance evaporation source is controlled at 395mA, the deposition rate is controlled at 11.0Å / s, and the deposition thickness of the waterproof membrane is controlled at 10nm.

[0066] Example 3 differs from Example 1 only in that the process parameters use the upper limit of a preset range.

[0067] In step S2, the physical thickness of each film layer is adjusted as follows: the first tantalum pentoxide film is 64nm, the second silicon dioxide film is 77nm, the third tantalum pentoxide film is 190nm, and the fourth silicon dioxide film is 247nm.

[0068] The corresponding electron gun and ion source parameters are set as follows: the electron gun current is 450mA when evaporating tantalum pentoxide, and the electron gun current is 250mA when evaporating silicon dioxide; the energy current of the ion source is 1000mA, and the neutralizer bias current is 1450mA.

[0069] In step S3, the heating current of the resistance evaporation source is controlled at 455mA, the deposition rate is controlled at 13.0Å / s, and the deposition thickness of the waterproof membrane is controlled at 13nm.

[0070] IV. Comparative Examples; To further illustrate the technical effects of the present invention, the following comparative examples are provided for comparison with Example 1.

[0071] Comparative Example 1: This comparative example aims to verify the key role of the "oxygen-rich environment" in step S2 in reducing the absorption rate.

[0072] The preparation process of this comparative example is basically the same as that of Example 1, except that: in the antireflection film deposition process in step S2, high-purity oxygen is not introduced into the vacuum chamber through a mass flow meter, that is, an oxygen-rich environment is not established, and the electron beam evaporation process of tantalum pentoxide and silicon dioxide is carried out only under conventional background vacuum conditions. All other process parameters (including film thickness, ion source parameters, and waterproof membrane process) are consistent with those of Example 1.

[0073] Comparative Example 2 aims to verify the effect of "ion source assistance" in step S2 on the compactness and adhesion of the film.

[0074] The preparation process of this comparative example is basically the same as that of Example 1, except that: during the antireflection film deposition process in step S2, the ion source is turned off and ion bombardment assistance is not performed. Deposition is carried out solely by electron gun evaporation. Due to the lack of auxiliary energy, the deposition rate is appropriately reduced (tantalum pentoxide is reduced to 1.5 Å / s, and silicon dioxide is reduced to 2.5 Å / s) to ensure film quality. The remaining film structure and waterproof membrane process are consistent with those of Example 1.

[0075] Comparative Example 3 aims to verify the synergistic effect of the "specific four-layer film thickness range" defined in this invention on optical performance.

[0076] This comparative example used the same oxygen-rich environment and ion source process as Example 1, but changed the physical thickness of each layer of the antireflection membrane, making it exceed the numerical range defined by this invention. The specific membrane thickness settings are as follows: First tantalum pentoxide film: 50nm (relatively thin); Second silicon dioxide film: 85nm (relatively thick); The third tantalum pentoxide film: 170nm (relatively thin); The fourth layer of silicon dioxide film: 255nm (relatively thick).

[0077] V. Performance testing; In order to objectively evaluate the performance of the non-contact fiber optic connector prepared by the present invention, the following performance tests were performed on the samples prepared in Examples 1-3 and Comparative Examples 1-3.

[0078] 1. Testing methods; Spectral performance test (SP8): The spectral data of the coated wafer in the communication band (1260nm-1650nm) was tested using a high-precision spectrophotometer.

[0079] Average transmittance: Calculate the average transmittance within this band.

[0080] Average absorption rate: calculated using the formula A=1-TR (assuming scattering is negligible), with a focus on the absorption loss of the film material.

[0081] Environmental reliability testing (SP9): Boiling test: Place the finished product in boiling water at 100℃ for 15 minutes, then remove and air dry naturally.

[0082] Adhesion test: After boiling in water, use 3M-600 test tape to adhere tightly to the film surface and quickly pull it up at a vertical angle to observe whether the film layer peels off.

[0083] High temperature and high humidity (double 85): Place the film at 85℃ and 85% relative humidity for 168 hours and observe the spectral drift (the smaller the drift, the denser the film layer and the less pores it has to absorb water).

[0084] 2. Test results; Table 1: Summary of test data for each group of samples; 3. Results Analysis; Regarding absorption rate: Example 1 established an oxygen-rich environment during the deposition process, resulting in an extremely low average absorption rate (0.02%), ensuring efficient signal transmission. In contrast, Comparative Example 1 did not introduce oxygen, leading to insufficient replenishment of oxygen released from the decomposition of tantalum pentoxide and silicon dioxide. This resulted in the formation of non-stoichiometric low-valence oxides, causing the absorption rate to surge to 0.55%, severely impacting the insertion loss of the fiber optic connector. This confirms the necessity of the "oxygen-rich environment" in step S2.

[0085] Regarding density and reliability: Example 1 employed ion-assisted deposition, resulting in a dense film structure after high-energy ion bombardment compaction. Tests showed no detachment after boiling in water and stretching with adhesive tape, and minimal spectral drift (<0.5 nm) after high-temperature and high-humidity aging at 85°C, indicating that water vapor could not penetrate the film. In contrast, Comparative Example 2, with the ion source turned off, although the deposition rate was reduced, still exhibited a columnar, loose structure. This led to poor adhesion after boiling (slight edge detachment), and water absorption through pores under high temperature and humidity caused refractive index changes, resulting in a significant spectral drift (>5.0 nm), failing to meet long-term reliability requirements.

[0086] Regarding film thickness matching: In Example 1, the film thickness was strictly controlled within the optimized range, achieving high transmittance over a wide wavelength range (1260-1650nm). In Comparative Example 3, although the material quality was acceptable (low absorption, good adhesion), the physical thickness deviated from the design value, disrupting the destructive interference conditions of the film system in a specific wavelength range. This resulted in an average transmittance of only 98.50%, failing to meet the optical specifications for high-performance connectors.

[0087] 4. Product performance verification; To further verify the applicability of the process of the present invention in the actual manufacturing of optical fiber connectors, the coated MT ferrule prepared in Example 1 was assembled into a 12-core APC optical fiber connector, and insertion loss test and end face three-dimensional interferometry were performed on it.

[0088] 4.1 Insertion loss test; The assembled connectors were tested using a multi-channel insertion loss meter. The commonly used wavelengths for communication were 1310nm and 1550nm.

[0089] Test results: As shown in Table 2, the insertion loss test data of the 12 channels under dual wavelengths accurately reflect the optical performance after coating. The insertion loss of all channels is below 0.5 dB (maximum value 0.49 dB), with most channels concentrated between 0.26 dB and 0.37 dB, exhibiting excellent optical transmission performance. This indicates that the antireflection coating system of this invention effectively reduces interface reflection, and the film structure does not introduce additional light scattering or absorption loss.

[0090] Table 2: Insertion loss test data of the finished product in Example 1 (unit: dB); 4.2 Three-dimensional interferometry of the end face; Since this invention relates to a vacuum heating environment (25-60°C), in order to confirm that the coating process does not affect the physical geometric parameters of the MT ferrule, an interferometer conforming to the IEC 61300-3-30 standard is used to perform 3D scanning on the end face of the finished product.

[0091] Test results: like Figure 3 As shown in Table 3, the end face of the ferrule maintained a good geometric morphology after coating.

[0092] Morphological features (combined) Figure 3 As can be seen from the 3D interferogram, the end face of the ferrule presents a regular and smooth curved shape, without any "saddle-shaped" twisting or local collapse caused by thermal stress, and the height difference between the optical fiber and the ferrule substrate transitions naturally.

[0093] Key data (refer to Table 3): Key indicators such as the radius of curvature of the X and Y axes and the fiber height are all within the standard allowable range (for example, the X-axis angle deviation is only 0.035°). This proves that the "low-temperature film formation" and "non-contact clamping" processes of this invention effectively release stress, while fully preserving the physical contact characteristics required for connector mating, thus providing optical functions to the end face.

[0094] Table 3: Key parameters for interferometric measurement of the finished product in Example 1; 5. In order to fully verify the advantages of the non-contact fiber optic connector prepared by the present invention in terms of optical performance and environmental reliability, the samples prepared in Example 1 were further subjected to spectral analysis and a number of rigorous reliability degradation tests.

[0095] 5.1 Spectral performance testing; The coated substrate was scanned across the entire wavelength range using a high-precision spectrometer (MSP-100B-W). Test results: such as Figure 4 As shown in Table 4, the antireflection coating of the present invention exhibits extremely excellent low reflectance characteristics in the 1260nm-1650nm communication band.

[0096] Curve characteristics (combined) Figure 4 The spectral curve is flat and without violent oscillations throughout the entire test band, indicating that the film refractive index is well matched and the thickness is precisely controlled.

[0097] Key data points (see Table 4): In the two core communication windows of 1310nm and 1550nm, the reflectivity is as low as 0.12% and 0.046% respectively, which is far better than the industry standard requirement of 0.25%.

[0098] Table 4: Key data points of spectral reflectance in Example 1; 5.2. Film adhesion and reliability testing; To verify the physical adhesion of the film layers under low-temperature deposition (25-60°C), this embodiment conducted four destructive tests that exceeded conventional standards. All tests were performed using 3M-600 high-viscosity test tape.

[0099] Table 5: Summary of film adhesion and reliability test results; 5.3. Results Analysis; The above test data strongly demonstrates the core advantages of the process of this invention: Excellent initial bonding strength: Projects 1-2 demonstrate that the membrane layer can resist boiling water penetration and mechanical scratch damage in its unaged state.

[0100] Excellent anti-aging performance: Projects 3-6 demonstrate that after experiencing short- to medium-term (24H-48H) thermal expansion and contraction stress, no peeling or micro-cracks occurred between the film layer and the ferrule substrate, and the initial bonding strength was maintained.

[0101] Extremely long-term reliability: Projects 7-8 demonstrate that even after aging for up to 168 hours (the standard double 85 or TC test cycle in the optical communication industry), and then subjected to secondary damage such as "boiling water" or "scratching," the film remains intact. This fully confirms the synergistic effect of "high-energy ion source-assisted deposition" and "specific deposition rate control" in step S2, solving the industry pain point of "film peeling and flaking after aging" in traditional low-temperature coating processes.

[0102] The above embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A coating process for a non-contact fiber optic connector, characterized in that, Includes the following steps: S1: Place the coating tray containing the MT insert in a vacuum chamber for vacuum treatment to achieve the preset vacuum level and control the coating temperature to 25℃-60℃. S2: While maintaining the coating temperature, the ion source is turned on for assistance, and the first tantalum pentoxide film, the second silicon dioxide film, the third tantalum pentoxide film and the fourth silicon dioxide film are sequentially deposited on the end face of the MT ferrule to form an antireflection film. In step S2, the deposition rate of tantalum pentoxide is controlled to be 2.0-3.0 Å / s, and the deposition rate of silicon dioxide is controlled to be 3.5-4.5 Å / s. The first tantalum pentoxide film and the second silicon dioxide film form an inner film layer pair, and the third tantalum pentoxide film and the fourth silicon dioxide film form an outer film layer pair. The thickness of the antireflection film satisfies the following relationship: in both the inner and outer film layer pairs, the thickness of the silicon dioxide film is greater than the thickness of the tantalum pentoxide film; the thicknesses of the tantalum pentoxide film and the silicon dioxide film in the outer film layer pair are greater than the thicknesses of the tantalum pentoxide film and the silicon dioxide film in the inner film layer pair, respectively. S3: Turn off the ion source and deposit a waterproof membrane on the surface of the antireflective membrane.

2. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In step S1, the preset standard is that the vacuum degree reaches or exceeds 1.0 × 10⁻⁶. -3 Pa; During the deposition process in step S2, the atmospheric pressure environment in the vacuum chamber is an oxygen-rich environment; High-purity oxygen is introduced into the vacuum chamber through a mass flow meter to maintain the working vacuum at a preset standard. Oxygen is used as a reaction gas to compensate for the oxygen vacancies generated by tantalum pentoxide and silicon dioxide during electron beam evaporation, so as to reduce the absorption rate of the antireflection film in the 1260nm-1650nm band.

3. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In step S2, the physical thickness range of each layer of the antireflective coating is as follows: The thickness of the first tantalum pentoxide film is 60nm-64nm; The thickness of the second silicon dioxide film is 73nm-77nm; The thickness of the third tantalum pentoxide film is 186nm-190nm; The thickness of the fourth silicon dioxide film is 243nm-247nm.

4. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In step S2, when electron beam evaporation is performed using an electron gun to deposit tantalum pentoxide and silicon dioxide films, the process parameters for controlling the electron gun are as follows: During the evaporation of tantalum pentoxide film, the electron gun current was controlled at 420mA±30mA; During the evaporation of the silicon dioxide film, the electron gun current is controlled at 220mA±30mA.

5. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In step S3, the deposition process of the waterproof membrane satisfies the following conditions: Deposition is performed using resistance evaporation; The deposition current was controlled at 425mA±30mA; The deposition rate was controlled at 12.0 Å / s ± 1.0 Å / s; The deposition thickness is 10nm-13nm.

6. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In step S2, the specific parameters for ion source assistance are controlled as follows: The ion source energy current is controlled at 900mA±100mA; The neutralizer bias current is controlled at 1350mA±100mA.

7. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: During the deposition process in steps S2 and S3, the rotation speed of the coating disk is 30 rpm.

8. The coating process for the non-contact fiber optic connector according to claim 1, characterized in that: In steps S2 and S3, a quartz crystal oscillator is used to monitor the deposition rate in real time at a sampling frequency of not less than 10 Hz. When the deviation between the monitored deposition rate and the target set value exceeds ±0.1 Å / s, the feedback system automatically adjusts the beam intensity of the electron gun or the heating power of the resistive evaporation source to correct the rate deviation back to the preset range within 0.5 seconds.

9. A manufacturing process for a non-contact fiber optic connector, characterized in that, The following steps are performed sequentially: SP1: Upper clamp; Install the MT core to be coated onto the coating tray, and ensure that the end faces of all cores are at the same height and the windows face the same direction; SP2: Cleaning; Place the clamped coated disc into an ultrasonic cleaner for cleaning to remove oil and particles from the end face; SP3: End face inspection; Perform microscopic inspection on the cleaned MT ferrule to confirm that there are no residual water stains or dirt on the end face; SP4: Install the coating tray that has passed inspection onto the rotating umbrella frame of the coating machine; SP5: Coating; using the coating process described in any one of claims 1-8, an anti-reflective coating and a waterproof coating are deposited on the end face of the MT ferrule; SP6: Lower the umbrella; after deposition is complete, remove the coating tray from the rotating umbrella frame; SP7: Lower clamp; Place the coating tray in a natural environment to cool for at least 10 minutes. After the temperature drops, remove the MT ferrule from the coating tray. SP8: Spectrophotometry; Use a spectrophotometer to test the reflectivity of the substrate coated in the same furnace to verify whether it meets the requirements in the 1260nm-1650nm wavelength band. SP9: Internal testing; Verification of sampled products, including placing the product in boiling water at 100°C for 15 minutes and then taking it out, and using 3M tape to perform an adhesion pull test to confirm that the film layer does not peel off. SP10: Visual inspection; The final product is inspected for appearance to confirm that there are no scratches, pits or defects on the film surface.

10. A non-contact fiber optic connector, characterized in that: The coating is prepared using any one of the coating processes described in claims 1-8; Alternatively, it can be prepared using the preparation process described in claim 9.

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