Practical Guide: Stripping, Splicing, and Operation Techniques for Polyimide Optical Fiber

Introduction: The Key to Efficiently Handling Specialty Coatings

The Polyimide (PI) coating is the core component that ensures the fiber can withstand extreme temperatures from -200℃ to +350℃. However, the PI coating's high strength and chemical stability mean it cannot be easily stripped using traditional mechanical strippers or alcohol, unlike standard acrylate coatings. This guide provides a set of verified procedures for stripping, cleaning, and splicing PI optical fiber.

I. Stripping Process: Say Goodbye to Mechanical Stripping, Embrace Thermal Tools

The key to stripping the PI coating is the use of a thermal stripping tool, which momentarily breaks down the molecular structure of the PI coating through high heat, causing it to soften or carbonize for damage-free removal.

1. Prepare Specialized Tools: Dedicated fiber thermal stripping tools (e.g., electric hot strippers with temperature and time control capabilities) must be used.
2. Set Thermal Stripping Parameters:
   • The recommended temperature setting is between 300℃ and 400℃.
   • The stripping time is typically set between 3 and 10 seconds. Specific parameters need fine-tuning based on the thermal stripper tool and the fiber coating thickness.
3. Perform Thermal Stripping: Place the fiber into the slot of the hot stripper, heat and hold for the set duration. Once heating is complete, remove the coating from the fiber quickly and smoothly. The stripping motion should be continuous to avoid secondary damage to the fiber.

II. Coating Cleaning: The Critical Step for Splicing Quality

After successful PI coating removal, microscopic carbonized residue or incompletely vaporized PI material may remain on the fiber surface, which can severely affect splicing quality.

1. Selection of Cleaning Agent: High-purity industrial-grade Isopropyl Alcohol (IPA) or anhydrous alcohol must be used for cleaning.
2. Cleaning Technique: Use lint-free lens paper or cotton swabs dampened with an appropriate amount of IPA.
   • Directional Cleaning: Wipe from the middle of the bare fiber toward both coating edges to ensure all residue is removed.
   • Ensure No Residue: It is essential to ensure that all visible coating and residue on the fiber surface are completely wiped clean.

III. Splicing and Cleaving Techniques

The splicing of PI fiber is fundamentally similar to standard single-mode fiber, but attention must be paid to adjusting the cleaving and arc discharge parameters during operation.

1. High-Precision Cleaving: Use a high-quality fiber cleaver to ensure the end face angle is less than 0.5 degrees. The quality of the fiber end face is a decisive factor in splicing loss.
2. Splicing Parameter Adjustment:
   • Splicing Mode: The standard SM (Single-Mode) fiber splicing mode can be used.
   • Arc Intensity: As the PI coating may be thicker than the standard coating or leave residue around the fusion splicer's V-grooves, it is recommended to fine-tune the splicer's arc intensity and pre-fusion time to accommodate any potential residue.
3. Splicing Quality Check: After splicing is complete, the splice point must be checked for loss and bubbles using the splicer's image or an Optical Time-Domain Reflectometer (OTDR). An acceptable splice joint should have a loss of less than 0.05 dB.

IV. Special Tip: Operating Carbon-Sealed Fiber

If using the Carbon-Sealed version of the OFSCN® PI fiber, the stripping method is consistent with the process above. However, when splicing, pay attention to the following:

• Splicer Settings: The carbon layer will vaporize during the splicing arc discharge. To prevent vaporization products from contaminating the electrodes or affecting the splice, it is recommended to add a cleaning discharge step in the splicer's sequence or regularly clean the splicer's V-grooves and electrodes.

Summary

The high performance of Polyimide fiber requires professional handling techniques. Mastering the three core skills—thermal stripping, IPA cleaning, and fine-tuning splicing parameters—will ensure the efficient deployment of OFSCN® PI fiber on-site, ultimately guaranteeing the long-term reliability of your system in 350℃ extreme environments.

Company Name	Beijing Dacheng Yongsheng Technology Co., Ltd. (DCYS)
Product Brand	OFSCN®
Product Model	300℃ SM Polyimide Optical Fiber (Maximum Operating Temperature 350℃)
Product Details Page	https://www.ofscn.org/optical-fibers/polyimide-coated-sm-300.html

Please strictly follow the operational procedures to ensure optimal splicing results and product performance!