Why can’t you use ordinary paper towels or a corner of clothing to wipe the connector?
In optical communication and optical sensor technology, the cleanliness of fiber optic end faces plays a decisive role in the transmission performance and stability of the entire system. Using ordinary paper towels or shirt corners to wipe fiber optic connectors (ferrule end faces) is an engineering malpractice that is strictly prohibited.
The underlying physics and optical engineering principles are mainly as follows:
1. Huge Differences in Microscopic Dimensions
The standard single-mode optical fiber has a core diameter of only about 9\ \mu\text{m} (e.g., standard G.652D fiber), and the cladding diameter is only 125\ \mu\text{m}. The diameter of ordinary paper lint and dust particles typically ranges from 1\ \mu\text{m} to tens of micrometers.
- Ordinary paper towels, when viewed under a microscope, are a network of rough plant fibers. Wiping them leaves behind a large amount of tiny paper lint and dust.
- Shirt corners and other everyday fabrics not only accumulate airborne dust and clothing fibers but also attach body oils and sweat.
Wiping with these easily deposits contaminants, several times larger than the fiber core, directly onto the core area, causing the beam to be blocked or scattered, and significantly increasing the system’s insertion loss ( IL ).
2. Mechanical Scratches and Geometric Shape Damage
The end faces of fiber optic connectors (such as FC/PC, FC/APC) are precision-polished ceramic or quartz surfaces with a specific micro-spherical shape.
- Ordinary paper towels and everyday clothing are not manufactured in a dust-free environment and often contain tiny hard particles (such as silica or metal dust).
- During the wiping process, these particles, under pressure, act like sandpaper, leaving tiny scratches on the surface of the fiber core and cladding. These permanent physical damages disrupt the interference matching of the end face, leading to severe degradation of return loss ( RL ) and causing strong reflections.
3. Electrostatic Adsorption Effect
When dry ordinary paper towels or clothing rub against the fiber optic connector, static electricity is easily generated due to differences in material electronegativity. The electric field produced by static electricity rapidly attracts free micro-dust particles in the surrounding air, leading to a phenomenon of “getting dirtier the more you wipe.”
4. Risk of “Burning” Under High Power
In high-power fiber optic systems (such as fiber lasers or high-power transmission links), if paper lint or skin oils remain on the end face, these organic materials will absorb laser energy intensely. The local temperature will rise sharply in an instant, causing the contaminants to carbonize directly and fuse-weld onto the fiber end face, completely destroying the component.
About OFSCN® Product Information
In fiber optic installation and daily maintenance, specialized lint-free wipes (such as Lint-free Wipes) combined with high-purity anhydrous alcohol (or specialized cleaning agents), or specialized one-click fiber cleaners are typically used for end face cleaning.
It should be clarified that such fiber cleaning papers, cleaning pens, and other auxiliary tools do not belong to the core product line of OFSCN®.
Beijing Da Cheng Yong Sheng Technology Co., Ltd. (OFSCN®) focuses on the research, development, and manufacturing of core specialty optical fibers and fiber Bragg grating (FBG) sensors. If your experiments or engineering projects involve high-quality optical fibers or high-precision temperature or strain measurements, we welcome you to learn about our core products.