250um loose tube optical cable and 900umtight buffer optical cable are two different types of optical cable, with the same diameter core, cladding and coating. Their differences are embodied in the structure, function, advantages, disadvantages and applications.
This article will illustrate these two different types of fiber optic cables for you.
Comparison
For the loose tube structure of the fiber, it places the fiber helically in the semi-rigid tube, so that the cable can be extended without stretching the fiber itself. As shown in the figure below, 250um fiber is made up of core, 125um cladding and 250um coating. In general, 250um loose tube cables fiber quantity can include 6-144cores. Except for the 6-m loose tube fiber optic cable, other fiber optic cables are usually composed of 12 cores.
Different from the above loose tube structure, for 900um tight fiber cable, there is a hard plastic layer is added out of the 250um loose tube, which can play a protective role. As shown in the figure above, 900um tight buffer cable is made of core, 125um cladding, 250um coating layer (the coating layer is soft plastic) and sheath layer (the sheath layer is hard plastic). Among them, the coating layer and sheath layer will help to isolate moisture from entering the core, and prevent the core from being exposed due to bending or compression when the optical cable is laid underwater. 900um tight buffer cable fiber quantity can be 2-144cores, and the tight buffer optical cable with larger number of fiber core is basically composed of 6 or 12 core as the basic unit.
Technical Specification
| Item | 250um loos tube | 900um tight buffer |
| Fiber core | 9um single mode, 50um or 62.5um multi-mode | 9um single mode, 50um or 62.5um multi-mode |
| cladding | 125um | 125um |
| coating | Soft plastic 250um | Soft plastic 250um |
| sheath | —— | Hard plastic 900um |
How to choose loose tube or tight buffer cables?
Due to 250um loose tube optical cable and 900um different functional characteristics, so they can be used in different applications.
| 250um loose tube | 900um tight buffer |
|
High-density; Low shrinkage and high tensile strength; Mechanical force; Moisture-proof; UV protection; High temperature resistance; Flame retardant LSZH polymer; Enhance system performance. |
High flexibility; High tensile strength; Good mechanical and temperature performance; Water blocking; UV protection; Higher survival standard; Glass fiber reinforced components; Easy termination. |
250um loose tube optical cable is suitable for harsh environment and is widely used outdoors. Compared with 900um tight buffer fiber optic cable, 250um loose tube fiber optic cable has higher tensile strength, moisture resistance and high temperature resistance, which is suitable for temperature change and high humidity environment. However, if excessive stretching is applied, the core will be pulled out of the gel. In addition, 250 um loose tube optical cable may not be a good choice when routing around multiple bends. The following will focus on why 250um loose sleeve optical cable is suitable for outdoor environment.
- Water proof - by filling the inner structure of the cable with gel, the fiber cable is protected to the greatest extent and effectively prevents water penetration.
- UV protection - the outer sheath contains carbon black, which can effectively prevent UV.
- Mechanical resistance - this kind of optical cable has an armored layer, which can withstand large mechanical force and improve durability.
- Pipeline space -the structure of 250um loose tube optical cable is different from that of 900um tight tube optical cable, and the size of 250um loose tube optical cable is almost one third of that of 900um tight buffer. Therefore, compared with 900um tight tube optical cable, 250um loose tube optical cable takes up less pipeline space, especially in the case of large number of optical fibers, which can effectively reduce the total installation cost.
The 900 um tight buffer fiber optic cable is very suitable for indoor applications. Compared with 250um loose tube fiber optic cable, 900um tight buffer fiber optic cable is more robust, which is more suitable for medium distance LAN / WAN connection or long distance indoor laying, or even direct underground laying. The following will focus on why 900um tight buffer optical cable is used in indoor environment.
- No gel is needed - indoor use does not require the use of protective gel, so it is more suitable for installation of risers perpendicular to buildings.
- Flexibility - there are no stiffeners to make the cable more flexible. In addition, it can be pulled around multiple bends or suspended vertically without worrying about the movement of the fiber mandrel
- Easy to splice - compared with the 250um loose tube cable, the 900um tight buffer cable is less fragile, and it's easier to handle each core. There is no need to clean up the messy gel, and there is no fan out kit for splicing or termination.
Summary
After making clear the structural and functional differences between 250um loose tube optical cable and 900um tight buffer optical cable, is it a good way to distinguish their applications! Before installation, be sure to select the appropriate optical cable according to the application environment.
So can you answer is it 250um loose tube or 900um tight buffer in fiber optic pigtails, patch cord or plc splitter?
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