/ From： / Review：8
All fiber construction engineers are aware that the first operation of a fusion splicer is not arc discharge, but fiber alignment. The core diameter of optical fiber is only 9 μm. The core of single-mode fiber is dozens of times thinner than human hair. When two optical fibers are butt-jointed at end faces, misalignment over 0.5 μm will cause significant splicing loss. The alignment procedure directly decides the final splicing quality.
PAS stands for Profile Alignment System, or lateral profile alignment system. In brief, cameras capture side images of fibers from two perpendicular directions (X-axis and Y-axis). Relying on the refractive index difference between fiber cladding and core, the system calculates the precise position of fibers and drives motors to align the two fibers coaxially.
Early fusion splicers applied 2-motor alignment, with one motor on X-axis and one on Y-axis. This design can finish basic alignment but has a critical drawback: fine-tuning is only available in one single direction. If the fiber end face has angular deviation, alignment accuracy will drop drastically.
The 4-motor PAS alignment system adds an extra group of motors. Apart from horizontal alignment along X and Y axes, it introduces Z-axis forward and backward feeding control. Two sets of motors work in coordination to adjust horizontal offset and control the gap between fiber end faces at the same time, placing fiber ends in the ideal docking position prior to arc discharge. A simple analogy: a 2-motor system is like shifting a table only left and right by hand, while a 4-motor system supports simultaneous horizontal and depth adjustment, resulting in remarkably higher positioning precision.
From field construction perspectives, the merits brought by 4-motor PAS alignment are reflected in three aspects:
1. Higher alignment precision
Bidirectional synchronous adjustment achieves more accurate core matching. The VAEYI FA-36 4-motor fiber fusion splicer is equipped with a high-precision 4-motor PAS alignment system and an industrial dual-CPU quad-core processor for image computation, delivering an average splicing loss of 0.02 dB for single-mode fiber, which ranks at the top level of the industry.
2. Compatibility with more fiber types
The 4-motor system boasts superior compatibility with various fibers. The FA-36 supports SM (G.652), MM (G.651), DS (G.653), EB (G.654), NZDS (G.655), BIF & UBIF (G.657) and other fiber types, covering almost all fiber models encountered in engineering sites.
3. Relatively loose requirements for fiber end faces
It is impossible to obtain perfectly flawless end angles during on-site fiber cleaving. The 4-motor alignment system features strong fault tolerance for minor angular deviations. High splicing success rate can still be guaranteed even when the cleaved end face is substandard.
In actual operation, the workflow of PAS alignment is as follows:Load fibers into clamps and close the windproof cover → Cameras capture lateral fiber images from X and Y directions simultaneously → The processor calculates position deviation between two fibers → Four motors adjust fiber positions separately → Arc discharge splicing starts after alignment confirmation.The whole process runs fully automatically. Operators only need to load fibers and shut the cover. For the FA-36 model, the full cycle from alignment to splicing completion takes roughly 8 seconds without any manual operation.
4-motor PAS alignment is a fundamental configuration, yet alignment structure alone is not enough for equipment selection. Matching processor performance is also essential. Slow image processing will render high alignment precision useless. Our splicer adopts an industrial dual-CPU quad-core processor with fast response in image recognition and motor control, which is one key factor enabling its 8-second full splicing cycle.
Besides, observation magnification matters. Alignment results must be checked on the display screen. Our splicer carries a 4.3-inch high-definition LCD screen supporting 180× simultaneous dual-view display and up to 300× independent single view magnification. Operators can clearly observe splicing conditions and instantly identify defects including core offset and air bubbles.
Compared with 2-motor splicers, the core advantage of 4-motor PAS alignment lies in additional Z-axis control, greatly lifting alignment precision and cleave fault tolerance. For construction teams engaged in long-distance trunk lines, FTTH home access and high-standard equipment room patch cord splicing, 4-motor splicers deliver tangible advantages in splicing quality and working efficiency. When choosing fusion splicers, users shall comprehensively evaluate multiple indicators including alignment system, processor performance, display magnification and splicing speed.
