The optical cable structure can be divided into two types according to whether the optical fiber is tightly wrapped: loose tube and tight buffered structure. These two structures are designed for different usage environments. The loose tube structure is mostly used for outdoor optical cables, and the tight buffered structure is mostly used for indoor optical cables (this article takes indoor breakout optical cables as an example). Let’s learn more about the differences between loose tube and tight buffered optical cables.
Loose Tube VS Tight Buffered Optical Cable
Both loose tube and tight buffered cables are multi-fiber cables composed of multiple optical fibers, however, they are different from each other. Let’s take a look at the main differences between them.
Loose Tube VS Tight Buffered Optical Cable: Difference in Structure
- The loose tube structure optical cable puts the 250um optical fiber into the loose tube made of high modulus material, and the loose tube is filled with ointment; the center of the cable core is a metal (non-metallic FRP optional) strengthening core. The loose tube is stranded around the central reinforcing core to form a circular cable core, and water-blocking filler is added to the gap in the cable core; Aluminum Polyethylene Laminate (APL) or corrugated Plastic Steel Plastic(PSP) is longitudinally wrapped and then extruded into polyethylene (PE) ) sheath into cables.
The indoor breakout optical cable uses a φ2.0mm single-core optical cable (φ 900um tight-buffered optical fiber, aramid fiber strengthening element) as a subunit. The optical cable sub-units are stranded on the FRP central strengthening core to form a cable core, and a layer of polyvinyl chloride (PVC) or low-smoke zero-halogen (LSZH) sheath is extruded to form a cable.
Loose Tube VS Tight Buffered Optical Cable: Difference in Protection
- The optical fibers of loose tube cables are placed within a loose ferrule filled with a gel that helps protect the fibers from moisture, making the cable ideal for harsh, high-humidity environments where water or condensation may be an issue.
- The optical fiber of the tight-buffered optical cable has two layers of protection (250um coating layer and 900um tight cladding).
Loose Tube VS Tight Buffered Optical Cable: Difference in Application
- Loose tube cables are used for outdoor aerial, duct and direct burial applications, local area network (LAN), metropolitan area network (MAN), wide area network (WAN), external equipment installation in long-distance and broadband networks, telecommunications, campus backbone networks, short-distance runs , data center, CATV, broadcasting, computer network system, user network system and 10, 40, 100Gbps Ethernet.
- Tight buffered cables are used indoors, data centers, backbone networks, horizontal cables, patch cords, equipment cables, LAN, WAN, storage area network (SAN), indoor long horizontal or vertical cabling.
Loose Tube VS Tight Buffered Optical Cable: Difference in Advantages
Tight-buffered cables are more expensive than loose-buffered cables because it uses more material in the cable construction. Due to the difference between 900um fibers and 250um fibers, tight-buffered cables hold a smaller number of fibers for the same diameter. In addition, tight-buffered cables are easier to install than loose-tube cables because there is no need to clean filling gel and they do not require splitters for splicing or termination.
Summary
Loose tube fiber optic cables provide stable and highly reliable optical transmission performance over a wide temperature range, provide the best protection for optical fibers under high tension, and can be easily moisture-proof with water-blocking grease. Tight-buffered cables offer high reliability, versatility, and flexibility in a smaller size and are easy to install.
