Detailed Analysis of Low-Loss Optical Fiber Splicing Technology: Influencing Factors and Practical Solutions

Detailed Analysis of Low-Loss Optical Fiber Splicing Technology: Influencing Factors and Practical Solutions

Optical fiber splicing is a core process in the construction and maintenance of optical communication lines. The level of splicing loss directly determines the stability of optical signal transmission, transmission distance, and overall system performance. To achieve low-loss splicing, it is necessary to comprehensively control various factors throughout the entire process and adopt targeted scientific solutions. This article will systematically analyze the key factors affecting splicing loss and practical response methods from nine core dimensions, providing professional references for engineering and technical personnel.

I. Optical Fiber Quality: The Fundamental Prerequisite * **Issues**: According to relevant specifications, a fiber mode field concentricity greater than **6%**, cladding non-circularity greater than **2%**, or axial misalignment and tilt are considered substandard.

**Impact**: These lead to core alignment deviations and signal transmission path shifts, significantly increasing loss.

**Solution**: Strictly screen qualified fibers and conduct sampling tests on incoming materials to ensure quality from the source.

II. Coating Stripping Quality: Avoiding Impurity Interference

The main function of the fibre coating is to protect the fibre cladding and core, and it must be completely removed before splicing. If the removal process is not standardised, leaving coating residues, or if the Miller pliers used have jaws that are too small, scratching the fibre cladding during removal can severely affect splicing quality. During the high-voltage arc splicing process, any remaining coating is melted by the high temperature, forming impurities, bubbles, or carbides that adhere to the fibre splice interface, disrupting smooth transmission of the optical signal and increasing splice loss.

Solution: Adjust the jaws of the Miller pliers according to the fibre specifications (such as 125μm cladding fibre), for example, using the VAEYI FSP-5 PRO Miller pliers, ensuring that the cladding is not damaged during stripping;  

for fibres that are difficult to strip, VAEYI FSP-160 can be used.

VAEYI FSP-200 PRO fibre optic thermal stripping pliers Achieve rapid and damage-free removal of the coating layer through precise temperature control, ensuring that the surface of the optical fibre cladding is smooth and residue-free after removal.

III. Fiber Cleanliness: Eliminating Interface Defects

Residues on the fiber surface, clamps, or V-grooves are major causes of loss.

Impact: Impurities melt during splicing to form bubbles or inclusions, causing signal refraction and scattering.

Solution:

Use specialized fiber cleaning clamps like the **VAEYI C101** or lint-free paper.

Use **99.9% industrial alcohol** (avoid 75% medical alcohol as it leaves a water film).

Wipe gently in a single direction along the fiber axis.，

IV. Cleaving Angle: Ensuring Interface Fit

After cleaning and stripping the fibre optic cable, it is necessary to use a fibre cleaver to cut a flat and smooth end face, which is the key prerequisite for achieving precise fibre alignment and reducing loss. If the cleaver is improperly adjusted, causing the fibre to be fragmented, the end face to have defects or chipping, or if the cutting angle is too large, the two fibres will not fit perfectly when spliced, resulting in gaps or misalignment at the fusion interface, leading to optical signal leakage and increased splice loss. 【Solution】: Pre-adjust the fibre cleaver to ensure the blade is sharp and the guide rails are parallel, controlling the cutting angle within 0.5°; for example, use the VAEYI P12+ one-step fibre cleaver.After cutting, use the end-face inspection function of the fusion splicer to check whether the end-face is flat and free of defects; non-compliant end-faces need to be recut until they meet the requirements.

V. Clamp and V-Groove Contamination: Ensuring Precise Positioning

The splicer fixture and V-groove are the core components for fibre positioning, and their condition directly affects the alignment accuracy of the fibre. If the fixture model is inappropriate, the surface is heavily contaminated, or the V-groove is scratched or worn, the fibre cannot be securely fixed, resulting in fibre slippage, insertion deviation, or axis misalignment during splicing, ultimately affecting the splicing quality and increasing loss.

[Solution]: Regularly clean the fixture, V-groove, splicer camera, and electrode rods with 99.9% industrial alcohol to remove surface dust, glass debris, and other impurities. If the fixture is loose, the V-groove is severely damaged, or there are scratches that prevent accurate positioning, the corresponding parts should be replaced promptly, or the manufacturer should be contacted for factory repair and calibration to ensure compliance with equipment positioning accuracy standards.

VI. Splicer Alignment Algorithm and Precision

Core alignment accuracy is a key equipment parameter.

The alignment algorithm accuracy of the fusion splicer and the motor control precision are key equipment parameters that determine the effectiveness of fibre fusion splicing. The core of fibre fusion splicing is achieving precise alignment of the cores of two fibres. If there is a deviation in the alignment algorithm or insufficient motor control precision, it can lead to core misalignment and displacement, resulting in significant fusion loss even if other operational procedures are followed. A high-performance fusion splicer typically achieves core alignment accuracy at the 0.1μm level, effectively ensuring fusion quality. [Solution]: Before splicing, use the splicer’s built-in motor calibration function to calibrate the fibre core alignment accuracy; if the alignment effect remains unsatisfactory after calibration, manually adjust the motor alignment and focus to optimise the alignment parameters; if there is a hardware fault in a VAEYIFA-66S6 motorised fusion splicer causing the alignment accuracy to fall short, contact the manufacturer for return and repair.

VII. Fusion Splicer Parameter Settings: Matching Fiber Types

Different fibers (SM, MM, NZ-DSF, DSF) require specific arc intensities and durations.

Impact: Mismatched settings lead to improper arc temperatures or propulsion force, increasing loss.

Solution: Select the correct preset mode (e.g., SM-SM, MM-MM).

VAEYI fusion splicers provide **8 preset modes** and support **100 custom modes** for manual fine-tuning of discharge and propulsion parameters.

VIII. Electrode Lifespan: Ensuring Arc Stability

Electrodes generate the high-temperature arc (above **2000°C**) for fusion.

Issues: Over time, tips become blunt and accumulate oxidation layers.

Impact: Unstable discharge and arc deviation.

Solution:

Clean tips with 99.9% alcohol swabs to remove oxidation.

Replace electrodes every **3,000 to 5,000 splices** (as per the manual) and perform discharge calibration after replacement.

IX. Splicing Environment: Avoiding External Interference

Temperature, humidity, air pressure, and dust affect splicing quality.

Impact: High humidity causes water condensation; low pressure in high altitudes alters arc distribution; dust causes interface impurities.

Solution:

Use the splicer’s "Arc Calibration" and "Motor Calibration" to adapt to the current environment.

In dusty areas, clean equipment frequently.

In extreme conditions, use protective shelters to keep temperature between **-10°C to 50°C** and humidity **≤85%** (no condensation).

Conclusion

Low-loss splicing is a systematic task requiring control over fiber quality, procedures, equipment, and environment. By using standardized processes, fine parameter adjustments, and regular maintenance, splicing loss can be kept within reasonable limits to ensure the stable operation of optical communication systems.