A corrosion-resistant special optical fiber and its fabrication process

Abstract

This invention belongs to the field of optical fiber technology, and particularly relates to a corrosion-resistant special optical fiber and its preparation process. The preparation process of the special optical fiber includes the following steps: (1) F-Ge doped quartz glass to form an optical fiber preform, which is then drawn into an optical fiber by heating; (2) Argon or oxygen plasma is used to clean the optical fiber to remove surface contaminants and activate the surface; (3) A nanoscale SiC thin film is deposited on the outer surface of the optical fiber using atomic layer deposition; (4) A polyether ether ketone coating is coated on the outer surface of the optical fiber, and after curing, a polytetrafluoroethylene composite coating is coated. After curing, a corrosion-resistant special optical fiber is obtained. The special optical fiber prepared by this invention is resistant to acids and alkalis, high temperature and high humidity, and has strong tensile and bending resistance. It also has excellent corrosion resistance, high temperature and high humidity stability, mechanical properties, and optical properties.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber technology, and particularly relates to a corrosion-resistant special optical fiber and its preparation process. Background Technology

[0002] Optical fiber, as an advanced transmission medium, has wide applications in many fields due to its unique physical and chemical properties, primarily in communications, medical, industrial, automotive, aerospace, and military sectors. With increasingly complex industrial environments, the demand for corrosion-resistant specialty optical fibers is continuously growing. These fibers are capable of long-term stable operation in harsh chemical environments and are widely used in corrosive environments such as chemical, marine, petroleum, and nuclear industries.

[0003] To improve corrosion resistance, current optical fibers are often doped with specific elements or coated with ceramic layers. While this improves corrosion resistance to some extent, it also increases the fiber's hardness and brittleness, reducing its tensile and bending strength. This makes it unable to withstand harsh environments like high temperature and humidity, resulting in significant transmission loss and poor durability in corrosive environments. In short, it's impossible to achieve a perfect balance of excellent corrosion resistance, high temperature and humidity stability, mechanical properties, and optical performance, thus reducing the fiber's practicality. Therefore, this invention provides a special optical fiber that combines excellent corrosion resistance, high temperature and humidity stability, mechanical properties, and optical performance to solve the aforementioned technical problems and meet practical application requirements. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a corrosion-resistant special optical fiber and its manufacturing process. This special optical fiber is resistant to acids and alkalis, high temperature and high humidity, and has strong tensile and bending resistance. It also has excellent corrosion resistance, high temperature and high humidity stability, mechanical properties and optical properties.

[0005] The objective of this invention is achieved as follows:

[0006] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0007] (1) F-Ge doped quartz glass is used to make an optical fiber preform, which is then heated and drawn to obtain an optical fiber;

[0008] (2) Use argon or oxygen plasma to clean the optical fiber, remove surface contaminants and activate the surface;

[0009] (3) A nanoscale SiC thin film was deposited on the outer surface of the optical fiber using atomic layer deposition;

[0010] (4) A layer of polyether ether ketone coating is applied to the outer surface of the optical fiber, and after curing, a layer of polytetrafluoroethylene composite coating is applied. After curing, a corrosion-resistant special optical fiber is obtained.

[0011] Preferably, the method for preparing the optical fiber preform in step (1) is as follows: First, clean the quartz glass liner to ensure that its surface is free of contamination. After drying, install it on an MCVD lathe and rotate it. Then, introduce silicon tetrachloride, germanium tetrachloride, carbon tetrafluoride and oxygen into the quartz glass liner. Use inert gas helium as the carrier gas to ensure uniform mixing. At 1600-2000℃, the gas undergoes an oxidation reaction on the inner wall of the liner. An F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain the optical fiber preform.

[0012] Preferably, the flow rates of silicon tetrachloride, germanium tetrachloride, carbon tetrafluoride, and oxygen are 1000–2000 sccm, 200–400 sccm, 50–100 sccm, and 2000–4000 sccm, respectively, and the processing time is 20–60 min.

[0013] Preferably, the heating temperature in step (1) is 2000-2200℃.

[0014] Preferably, the flow rate of argon or oxygen in step (2) is 20-50 sccm, and the processing time is 15-30 min.

[0015] Preferably, the deposition method of the nanoscale SiC thin film in step (3) is as follows: placing the optical fiber in an atomic layer deposition device, and alternately introducing silicon tetrachloride and propylene at 300-400°C, so that a self-limiting surface reaction occurs on the surface of the optical fiber, and SiC thin film is grown layer by layer.

[0016] Preferably, the flow rates of silicon tetrachloride and propylene are both 10-50 sccm, the pulse duration is both 0.1-1.0 seconds, the number of cycles is 500-1000, and the thickness of the SiC film is 50-100 nm.

[0017] Preferably, the coating method of polyether ether ketone in step (4) is as follows: 98% concentrated sulfuric acid and polyether ether ketone are mixed and stirred at 75-85°C for 2-4 hours to obtain a coating solution with a concentration of 10-15% w / v. The coating solution is then sprayed onto the outer surface of the optical fiber to form a liquid film, and after step curing, a polyether ether ketone coating is formed.

[0018] Preferably, the thickness of the polyetheretherketone coating is 5-10 μm, and the stepped curing process is as follows: first, curing at 200-220°C for 40-60 min, then curing at 280-320°C for 40-60 min, and finally curing at 360-380°C for 60-80 min under nitrogen protection.

[0019] Preferably, the polytetrafluoroethylene composite coating in step (4) is made from the following raw materials in the following mass percentages: 65-85% polytetrafluoroethylene, 10-30% nano-alumina, and 2-6% silane coupling agent. The nano-alumina has a particle size of 10-50 nm, and the silane coupling agent is KH-560 or A-171.

[0020] Preferably, the polytetrafluoroethylene composite coating is applied by spraying, with a spray thickness of 100-120 μm. After spraying, it is cured by controlling the heating rate at 3℃ / min, raising the temperature from room temperature to 360-380℃, and curing under nitrogen protection for 20-40 min.

[0021] The present invention also discloses a corrosion-resistant special optical fiber, which is prepared by the special optical fiber preparation process described above.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The optical fiber preform of the present invention deposits an F-Ge co-doped quartz layer inside a quartz glass tube, which can reduce optical fiber transmission loss and improve the heat resistance and corrosion resistance of the optical fiber.

[0024] 2. This invention uses atomic layer deposition to deposit nanoscale SiC thin films on the outer surface of optical fibers, which can block the penetration of corrosive media and thus improve the corrosion resistance of optical fibers.

[0025] 3. This invention coats the outer surface of an optical fiber with a polyetheretherketone (PEEK) coating, which is then cured and coated with a polytetrafluoroethylene (PTFE) composite coating. PEEK has excellent chemical stability and can maintain its performance under various harsh chemical environments. This not only improves the mechanical strength of the optical fiber but also enhances its weather resistance. The PTFE composite coating is made of PTFE, nano-alumina, and a silane coupling agent. Using PTFE as the main matrix imparts chemical inertness, while nano-alumina enhances its density to prevent corrosive media from entering. The silane coupling agent improves the adhesion between the coating and the fiber core. Coating with the PTFE composite coating further enhances the corrosion resistance and abrasion resistance of the optical fiber. The double-layer, step-by-step coating ensures the uniformity and firmness of the coating, significantly improving the durability of the optical fiber in corrosive environments.

[0026] 4. The special optical fiber prepared by the process of this invention shows an increase in transmission loss of less than 0.2 dB / km after immersion in 5% HCl or 5% NaOH solution for 30 days, an increase in transmission loss of less than 0.3 dB / km after 1000 hours at 85°C and 85% humidity, an increase in transmission loss of less than or equal to 0.15 dB / km at a tensile strength of 5 GPa and a bending radius of 5 mm, and a transmission loss of less than or equal to 0.25 dB / km at a wavelength of 1550 nm. This means that the special optical fiber of this invention is resistant to acids and alkalis, high temperature and humidity, and has strong tensile and bending resistance, while also exhibiting excellent corrosion resistance, high temperature and humidity stability, mechanical properties, and optical properties. Detailed Implementation

[0027] The present invention will now be described in more detail through specific embodiments.

[0028] Example 1

[0029] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0030] (1) First, clean the quartz glass liner tube to ensure that its surface is free of contamination. After drying, install it on the MCVD lathe and rotate it. Then, introduce silicon tetrachloride at a flow rate of 1000 sccm, germanium tetrachloride at a flow rate of 200 sccm, carbon tetrafluoride at a flow rate of 50 sccm, and oxygen at a flow rate of 2000 sccm into the quartz glass liner tube for 60 minutes. Use inert gas helium as the carrier gas to ensure uniform mixing. At 1600℃, the gas undergoes an oxidation reaction on the inner wall of the liner tube, and an F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2000℃.

[0031] (2) Use argon plasma with a flow rate of 20 sccm to clean the optical fiber for 30 min to remove surface contaminants and activate the surface;

[0032] (3) The optical fiber is placed in an atomic layer deposition device, and silicon tetrachloride and propylene are alternately introduced at 300°C. The flow rate of silicon tetrachloride and propylene is 10 sccm, the pulse time is 1.0 seconds, and the number of cycles is 500. A self-limiting surface reaction occurs on the surface of the optical fiber, and SiC film is grown layer by layer. The total thickness of the SiC film is 50 nm.

[0033] (4) Mix 98% concentrated sulfuric acid and polyether ether ketone, stir at 75°C for 4 hours to obtain a coating solution with a concentration of 10% w / v, then spray the coating solution onto the outer surface of the optical fiber to form a liquid film, cure at 200°C for 60 min, then cure at 280°C for 60 min, and finally cure at 360°C for 80 min under nitrogen protection to obtain a polyether ether ketone coating with a thickness of 5 μm; spray a polytetrafluoroethylene composite coating made of 65 wt% polytetrafluoroethylene, 30 wt% nano alumina (particle size of 10 nm) and 5 wt% silane coupling agent KH-560 onto the outer surface of the optical fiber with a spray thickness of 100 μm, cure after spraying, control the heating rate to be 3°C / min, raise the temperature from room temperature to 360°C, and cure under nitrogen protection for 40 min to obtain a corrosion-resistant special optical fiber.

[0034] Example 2

[0035] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0036] (1) First, clean the quartz glass liner tube to ensure that its surface is free of contamination. After drying, install it on the MCVD lathe and rotate it. Then, introduce silicon tetrachloride at a flow rate of 1200 sccm, germanium tetrachloride at a flow rate of 250 sccm, carbon tetrafluoride at a flow rate of 65 sccm, and oxygen at a flow rate of 2500 sccm into the quartz glass liner tube for 50 minutes. Use inert gas helium as the carrier gas to ensure uniform mixing. At 1700℃, the gas undergoes an oxidation reaction on the inner wall of the liner tube, and an F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2100℃.

[0037] (2) Use oxygen plasma with a flow rate of 30 sccm to clean the optical fiber for 25 min to remove surface contaminants and activate the surface.

[0038] (3) The optical fiber was placed in an atomic layer deposition device, and silicon tetrachloride and propylene were alternately introduced at 320°C. The flow rates of silicon tetrachloride and propylene were both 20 sccm, the pulse time was 0.8 seconds, and the number of cycles was 600. A self-limiting surface reaction occurred on the surface of the optical fiber, and SiC thin films were grown layer by layer. The total thickness of the SiC thin film was 60 nm.

[0039] (4) Mix 98% concentrated sulfuric acid and polyether ether ketone, stir at 78℃ for 3.5h to obtain a coating solution with a concentration of 11% w / v, then spray the coating solution onto the outer surface of the optical fiber to form a liquid film, cure at 205℃ for 55min, then cure at 290℃ for 55min, and finally cure at 365℃ for 70min under nitrogen protection to obtain a polyether ether ketone coating with a thickness of 6μm; spray a polytetrafluoroethylene composite coating made of 70wt% polytetrafluoroethylene, 24wt% nano alumina (particle size of 20nm) and 6wt% silane coupling agent A-171 onto the outer surface of the optical fiber with a spray thickness of 110μm, cure after spraying, control the heating rate to be 3℃ / min, raise the temperature from room temperature to 365℃, and cure under nitrogen protection for 35min to obtain a corrosion-resistant special optical fiber.

[0040] Example 3

[0041] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0042] (1) First, clean the quartz glass liner tube to ensure that its surface is free of contamination. After drying, install it on the MCVD lathe and rotate it. Then, introduce silicon tetrachloride at a flow rate of 1500 sccm, germanium tetrachloride at a flow rate of 300 sccm, carbon tetrafluoride at a flow rate of 80 sccm, and oxygen at a flow rate of 3000 sccm into the quartz glass liner tube for 40 minutes. Use inert gas helium as the carrier gas to ensure uniform mixing. At 1800℃, the gas undergoes an oxidation reaction on the inner wall of the liner tube, and an F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2100℃.

[0043] (2) Use argon plasma with a flow rate of 35 sccm to clean the optical fiber for 20 min to remove surface contaminants and activate the surface;

[0044] (3) The optical fiber is placed in an atomic layer deposition device, and silicon tetrachloride and propylene are alternately introduced at 350°C. The flow rate of silicon tetrachloride and propylene is 30 sccm, the pulse time is 0.5 seconds, and the number of cycles is 800. A self-limiting surface reaction occurs on the surface of the optical fiber, and SiC film is grown layer by layer. The total thickness of the SiC film is 80 nm.

[0045] (4) Mix 98% concentrated sulfuric acid and polyether ether ketone, stir at 80℃ for 3h to obtain a coating solution with a concentration of 12% w / v, then spray the coating solution onto the outer surface of the optical fiber to form a liquid film, cure at 210℃ for 50min, then cure at 300℃ for 50min, and finally cure at 370℃ for 70min under nitrogen protection to obtain a polyether ether ketone coating with a thickness of 8μm; spray a polytetrafluoroethylene composite coating made of 75wt% polytetrafluoroethylene, 20wt% nano alumina (particle size of 30nm) and 5wt% silane coupling agent KH-560 onto the outer surface of the optical fiber with a spray thickness of 110μm, cure after spraying, control the heating rate to be 3℃ / min, raise the temperature from room temperature to 370℃, and cure under nitrogen protection for 30min to obtain a corrosion-resistant special optical fiber.

[0046] Example 4

[0047] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0048] (1) First, clean the quartz glass liner tube to ensure that its surface is free of contamination. After drying, install it on the MCVD lathe and rotate it. Then, introduce silicon tetrachloride at a flow rate of 1800 sccm, germanium tetrachloride at a flow rate of 350 sccm, carbon tetrafluoride at a flow rate of 90 sccm, and oxygen at a flow rate of 3500 sccm into the quartz glass liner tube for 30 minutes. Use inert gas helium as the carrier gas to ensure uniform mixing. At 1900℃, the gas undergoes an oxidation reaction on the inner wall of the liner tube, and an F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2200℃.

[0049] (2) Use oxygen plasma with a flow rate of 40 sccm to clean the optical fiber for 20 min to remove surface contaminants and activate the surface.

[0050] (3) The optical fiber was placed in an atomic layer deposition device, and silicon tetrachloride and propylene were alternately introduced at 380°C. The flow rates of silicon tetrachloride and propylene were both 40 sccm, the pulse time was 0.3 seconds, and the number of cycles was 850. A self-limiting surface reaction occurred on the surface of the optical fiber, and SiC thin films were grown layer by layer. The total thickness of the SiC thin film was 85 nm.

[0051] (4) Mix 98% concentrated sulfuric acid and polyether ether ketone, stir at 82℃ for 2.5h to obtain a coating solution with a concentration of 13% w / v, then spray the coating solution onto the outer surface of the optical fiber to form a liquid film, cure at 210℃ for 50min, then cure at 310℃ for 50min, and finally cure at 370℃ for 60min under nitrogen protection to obtain a polyether ether ketone coating with a thickness of 8μm; spray a polytetrafluoroethylene composite coating made of 80wt% polytetrafluoroethylene, 18wt% nano alumina (particle size of 40nm) and 2wt% silane coupling agent A-171 onto the outer surface of the optical fiber with a spray thickness of 110μm, cure after spraying, control the heating rate to be 3℃ / min, raise the temperature from room temperature to 370℃, and cure under nitrogen protection for 30min to obtain a corrosion-resistant special optical fiber.

[0052] Example 5

[0053] A fabrication process for a corrosion-resistant special optical fiber includes the following steps:

[0054] (1) First, clean the quartz glass liner tube to ensure that its surface is free of contamination. After drying, install it on the MCVD lathe and rotate it. Then, introduce silicon tetrachloride at a flow rate of 2000 sccm, germanium tetrachloride at a flow rate of 400 sccm, carbon tetrafluoride at a flow rate of 100 sccm, and oxygen at a flow rate of 4000 sccm into the quartz glass liner tube for 20 minutes. Use inert gas helium as the carrier gas to ensure uniform mixing. At 2000℃, the gas undergoes an oxidation reaction on the inner wall of the liner tube, and an F-Ge co-doped quartz layer is deposited inside the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2200℃.

[0055] (2) Use argon plasma with a flow rate of 50 sccm to clean the optical fiber for 15 min to remove surface contaminants and activate the surface.

[0056] (3) The optical fiber is placed in an atomic layer deposition device, and silicon tetrachloride and propylene are alternately introduced at 400°C. The flow rate of silicon tetrachloride and propylene is 50 sccm, the pulse time is 0.1 seconds, and the number of cycles is 1000. A self-limiting surface reaction occurs on the surface of the optical fiber, and SiC film is grown layer by layer. The total thickness of the SiC film is 100 nm.

[0057] (4) Mix 98% concentrated sulfuric acid and polyether ether ketone, stir at 85℃ for 2h to obtain a coating solution with a concentration of 15% w / v, then spray the coating solution onto the outer surface of the optical fiber to form a liquid film, cure at 220℃ for 40min, then cure at 320℃ for 40min, and finally cure at 380℃ for 60min under nitrogen protection to obtain a polyether ether ketone coating with a thickness of 10μm; spray a polytetrafluoroethylene composite coating made of 85wt% polytetrafluoroethylene, 10wt% nano alumina (particle size of 50nm) and 5wt% silane coupling agent KH-56 onto the outer surface of the optical fiber with a spray thickness of 120μm, cure after spraying, control the heating rate to be 3℃ / min, raise the temperature from room temperature to 380℃, and cure under nitrogen protection for 20min to obtain a corrosion-resistant special optical fiber.

[0058] Comparative Example 1

[0059] The difference between Comparative Example 1 and Example 3 is that in step (1): First, the quartz glass liner is cleaned to ensure that its surface is free of contamination. After drying, it is installed on an MCVD lathe and rotated. Then, silicon tetrachloride with a flow rate of 1500 sccm, carbon tetrafluoride with a flow rate of 80 sccm, and oxygen with a flow rate of 3000 sccm are introduced into the quartz glass liner for 40 minutes. Inert gas helium is used as the carrier gas to ensure uniform mixing. The gas is oxidized on the inner wall of the liner at 1800°C, and an F-Ge co-doped quartz layer is deposited in the quartz glass tube to obtain an optical fiber preform. Finally, the optical fiber is drawn by heating at 2100°C. The remaining steps are the same as in Example 3.

[0060] Comparative Example 2

[0061] The difference between Comparative Example 2 and Example 3 is that Comparative Example 2 does not include step (3), while the remaining steps are the same as those in Example 3.

[0062] Comparative Example 3

[0063] The difference between Comparative Example 3 and Example 3 is that in step (4): 98% concentrated sulfuric acid and polyether ether ketone are mixed and stirred at 80°C for 3 hours to obtain a coating solution with a concentration of 12% w / v. The coating solution is then sprayed onto the outer surface of the optical fiber to form a liquid film. It is cured at 210°C for 50 minutes, then cured at 300°C for 50 minutes, and finally cured at 370°C for 70 minutes under nitrogen protection to form a polyether ether ketone coating with a thickness of 8 μm, thus obtaining the special optical fiber. The remaining steps are the same as in Example 3.

[0064] Comparative Example 4

[0065] The difference between Comparative Example 4 and Example 3 is that in step (4): a polytetrafluoroethylene composite coating made of 75 wt% polytetrafluoroethylene, 20 wt% nano alumina (particle size of 30 nm) and 5 wt% silane coupling agent KH-560 is sprayed onto the outer surface of the optical fiber with a coating thickness of 110 μm. After spraying, the coating is cured, and the heating rate is controlled at 3 °C / min. The temperature is raised from room temperature to 370 °C and cured for 30 min under nitrogen protection to obtain a special optical fiber. The remaining steps are the same as in Example 3.

[0066] The special optical fibers prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to performance testing, and the test results are shown in Table 1.

[0067] Corrosion resistance test: The special optical fibers prepared in Examples 1-5 and Comparative Examples 1-4 were immersed in 5% HCl or 5% NaOH solution for 30 days, and the increase in transmission loss after immersion was measured compared with that before immersion.

[0068] High temperature and high humidity stability test: The special optical fibers prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to 85°C and 85% humidity for 1000 hours, and the increase in transmission loss after treatment was measured compared with that before treatment.

[0069] Mechanical performance testing: The increase in transmission loss of the special optical fibers prepared in Examples 1-5 and Comparative Examples 1-4 was measured at a tensile strength of 5 GPa and a bending radius of 5 mm.

[0070] Optical performance testing: The transmission loss of the special optical fibers prepared in Examples 1-5 and Comparative Examples 1-4 at a wavelength of 1550 nm was measured.

[0071] Table 1

[0072]

[0073]

[0074] The test results above show that the transmission loss increase of the special optical fibers prepared in Examples 1-5 of this invention after immersion in 5% HCl or 5% NaOH solution for 30 days is less than 0.2 dB / km, while the transmission loss increase of the special optical fibers prepared in Comparative Examples 1-4 after immersion in 5% HCl or 5% NaOH solution for 30 days is greater than 0.4 dB / km. In particular, the transmission loss increase of the special optical fiber prepared in Comparative Example 4 without polytetrafluoroethylene composite coating is as high as 0.55 dB / km. This indicates that the special optical fibers prepared in Examples 1-5 of this invention are resistant to acids and alkalis and have excellent corrosion resistance.

[0075] The special optical fibers prepared in Examples 1-5 of this invention showed an increase in transmission loss of less than 0.3 dB / km after 1000 hours at 85°C and 85% humidity, while the special optical fibers prepared in Comparative Examples 1-4 showed an increase in transmission loss of more than 0.45 dB / km after 1000 hours at 85°C and 85% humidity. In particular, the special optical fiber prepared in Comparative Example 3 without polyetheretherketone coating showed an increase in transmission loss as high as 0.60 dB / km. This indicates that the special optical fibers prepared in Examples 1-5 of this invention can withstand high temperature and high humidity and have excellent high temperature and high humidity stability.

[0076] The special optical fibers prepared in Examples 1-5 of this invention all showed an increase in transmission loss of less than or equal to 0.15 dB / km at a tensile strength of 5 GPa and a bending radius of 5 mm. In contrast, the special optical fibers prepared in Comparative Examples 1-4 all showed an increase in transmission loss of more than 0.3 dB / km at a tensile strength of 5 GPa and a bending radius of 5 mm. In particular, the special optical fiber prepared in Comparative Example 3 without a polyetheretherketone coating showed an increase in transmission loss as high as 0.57 dB / km. This indicates that the special optical fibers prepared in Examples 1-5 of this invention have strong tensile and bending resistance and excellent mechanical properties.

[0077] The special optical fibers prepared in Examples 1-5 of this invention all have a transmission loss of less than or equal to 0.25 dB / km at a wavelength of 1550 nm, while the special optical fibers prepared in Comparative Examples 1-4 all have a transmission loss of greater than 0.4 dB / km at a wavelength of 1550 nm. In particular, the special optical fiber prepared in Comparative Example 3 without polyetheretherketone coating has a transmission loss as high as 0.58 dB / km, indicating that the special optical fibers prepared in Examples 1-5 of this invention have excellent optical performance.

[0078] Therefore, the special optical fibers prepared in Examples 1 to 5 of the present invention are not only resistant to acids and alkalis and have excellent corrosion resistance, but also resistant to high temperature and high humidity, with strong tensile and bending resistance, and have excellent high temperature and high humidity stability, mechanical properties and optical properties.

[0079] The above embodiments are merely illustrative of the present invention and are not intended to limit the invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A process for the preparation of corrosion resistant specialty optical fiber, characterized in that, The method comprises the following steps: (1) a quartz glass doped with F-Ge is made into an optical fiber preform, and the optical fiber is drawn by heating; (2) the optical fiber is cleaned by using argon or oxygen plasma to remove surface contaminants and activate the surface; (3) a nanoscale SiC film is deposited on the outer surface of the optical fiber by using an atomic layer deposition method; (4) a layer of polyether ether ketone coating is coated on the outer surface of the optical fiber, and after curing, a layer of polytetrafluoroethylene composite coating is coated, and after curing, a corrosion-resistant special optical fiber is obtained; The deposition method of the nanoscale SiC film in step (3) is as follows: the optical fiber is placed in an atomic layer deposition device, silicon tetrachloride and propylene are alternately introduced at 300-400 DEG C, a self-limiting surface reaction occurs on the surface of the optical fiber, and a SiC film is grown layer by layer; The flow rates of the silicon tetrachloride and propylene are both 10-50 sccm, the pulse times are both 0.1-1.0 seconds, the cycle times are 500-1000 times, and the thickness of the SiC film is 50-100 nm; The coating method of the polyether ether ketone coating in step (4) is as follows: 98% concentrated sulfuric acid and polyether ether ketone are mixed, stirred at 75-85 DEG C for 2-4 hours to obtain a coating solution with a concentration of 10-15% w / v, the coating solution is sprayed on the outer surface of the optical fiber to form a liquid film, and after step curing, a polyether ether ketone coating is formed; The thickness of the polyether ether ketone coating is 5-10 microns, and the step curing process is as follows: first, curing at 200-220 DEG C for 40-60 min, then curing at 280-320 DEG C for 40-60 min, and finally curing at 360-380 DEG C for 60-80 min under nitrogen protection; The polytetrafluoroethylene composite coating in step (4) is made from the following mass percentage raw materials: polytetrafluoroethylene 65-85%, nano-alumina 10-30%, and silane coupling agent 2-6%; wherein the particle size of the nano-alumina is 10-50 nm, and the silane coupling agent is KH-560 or A-171.

2. The process for making corrosion resistant specialty optical fiber as claimed in claim 1 wherein, The preparation method of the optical fiber preform in step (1) is as follows: first, clean the quartz glass liner to ensure that the surface is free of contamination, dry it, and then install it on an MCVD lathe and rotate it, then introduce silicon tetrachloride, germanium tetrachloride, carbon tetrafluoride and oxygen into the quartz glass liner, use inert gas helium as the carrier gas to ensure uniform mixing, and make the gas react on the inner wall of the liner at 1600-2000 DEG C to deposit a F-Ge co-doped quartz layer in the quartz glass tube to obtain an optical fiber preform.

3. The process for making corrosion resistant specialty optical fiber as claimed in claim 2, wherein, The flow rates of the silicon tetrachloride, germanium tetrachloride, carbon tetrafluoride and oxygen are 1000-2000 sccm, 200-400 sccm, 50-100 sccm and 2000-4000 sccm respectively, and the processing time is 20-60 min.

4. The process for making corrosion resistant specialty optical fiber as claimed in claim 1 wherein, The heating temperature in step (1) is 2000-2200 DEG C.

5. The process for making corrosion resistant specialty optical fiber as claimed in claim 1, wherein, The argon or oxygen flow rate in step (2) is 20-50 sccm, and the processing time is 15-30 min.

6. The process for making corrosion resistant specialty optical fiber as claimed in claim 1 wherein, The coating method of the polytetrafluoroethylene composite coating is spraying, the spraying thickness is 100-120 μm, and the spraying is followed by solidification, the temperature is raised from room temperature to 360-380 DEG C at a rate of 3 DEG C / min, and the solidification is performed under nitrogen protection for 20-40 min.

7. A corrosion resistant specialty optical fiber, characterized by, The special optical fiber is prepared by the preparation process of any one of claims 1-6.

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