I. Fusion Loss Testing with Standard Instruments
The core goal after calibration is to reduce and stabilize fusion loss, which requires measuring the actual loss value using specialized equipment.
1. OTDR (Optical Time Domain Reflectometer) Bidirectional Testing Method
Connect both ends of the fiber under test to an OTDR for bidirectional testing.
Take the average of the loss values measured in both directions as the final result to eliminate measurement bias caused by Rayleigh scattering.
Acceptance Standard: Single-mode fiber fusion splice loss ≤ 0.05dB, ideal value ≤ 0.02dB.
2. Light Source + Optical Power Meter Insertion Method
Use a stable light source and an optical power meter to measure the change in optical power before and after fusion splicing.
During operation, the reference value can be zeroed first, and then the loss after fusion splicing can be measured to improve accuracy.
Advantages: Low cost, simple operation, suitable for rapid on-site verification.
II. Fiber Axial and Angular Deviation Detection
Calibration directly affects the fiber core alignment accuracy and requires verification using a high-precision imaging system.
1. Microscopic Imaging System Inspection
Observe the fiber core alignment before and after fusion splicing using the X/Y-axis microscope built into the fusion splicer.
Check for cladding misalignment, fiber core offset, or end-face tilt.
Permissible errors: Axial deviation < 0.5μm, angular deviation < 0.5°.
2. Interferometry Technology (Suitable for high-precision scenarios)
Use an optical interferometer to detect end-face angles and alignment consistency; commonly used for laboratory-level verification.
III. V-groove and Electrode Status Recheck
After calibration, confirm that key components are in optimal working condition.
1. V-groove Cleanliness Check
After wiping with alcohol wipes, confirm under a microscope that there is no dust or fiber debris residue.
Inadequate cleaning can cause fiber positioning misalignment, affecting alignment accuracy.
2. Electrode Discharge Correction Verification
After executing the "discharge correction" procedure, observe whether the arc is centered and stable.
If the arc is offset or flickering, the electrode needs to be cleaned again or replaced.
IV. Heat Shrink Protection Performance Test Mechanical protection of the splice is equally important; the heating furnace must be verified to be functioning correctly.
1. Heat Shrink Tube Heating Uniformity
Use standard heat shrink tubing for heating and observe whether the shrinkage is uniform and free of air bubbles.
After heating, the tubing should be transparent, tightly attached to the optical fiber, and the steel rod should be centered and fixed.
2. Heating Time and Temperature Matching
Different tubing sizes (e.g., 20mm, 60mm) require different heating times; these must be set according to the equipment instructions.
V. Repeatability and Stability Verification Verify the long-term stability after calibration through repeated operations.
1. Average Value of 5 or More Continuous Splices
Use the same batch of standard optical fibers for repeated splicing, recording the estimated loss and measured OTDR value each time.
Analyze the data dispersion, eliminate outliers, and ensure the results are repeatable.
2. Environmental Adaptability Test (Optional)
Retest in an environment with large temperature variations to verify the effectiveness of the temperature compensation function.
