Four Pairs of Fiber Optic Cables

Fiber optic cables are one of the fastest growing transmission mediums for both new cabling installations and upgrades. They are ideal for high-data-rate systems such as Gigabit Ethernet, multimedia, Fiber Channel, or any other network that requires the transfer of large, bandwidth-consuming data files, particularly over long distances. Generally we can divide fiber optic cables into different types based on different classification standards. This post will introduce and compare four pairs of fiber optic cables, which are multimode and single-mode cables, simplex and duplex cables, PVC and LSZH cables, distribution-style and breakout-style cables.

Multimode vs. Single-mode Cables

Multimode and single-mode cables are the most common classification of fiber optic cables. Multimode fiber optic cables have a large diameter core and multiple pathways of light. The most two common core size of multimode cables are 50 micron and 62.5 micron. While single-mode cables have a small 8-10 micron core and only one pathway of light. With only a single wavelength of light passing through the core, single-mode cables realign the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode cables do. In addition, single-mode cables provide 50 times longer distance than multimode cables. Consequently, single-mode cables are typically used in high-bandwidth applications and long-haul network connections, while multimode cables are deployed in short distance applications. Both multimode and single-mode cables can be terminated at both ends with the same or different fiber optic connectors to form fiber optic jumper cables, such as LC to LC multimode fiber optic patch cable(as shown in the following picture), or LC to SC single-mode fiber patch cable.


Simplex vs. Duplex Cables

The second pair of fiber optic cables are simplex and duplex cables. Multimode and single-mode cables both can be simplex or duplex. Simplex cables consist of one fiber, while duplex zipcord cables have two fibers joined with a thin web. Simplex and duplex zipcord cables are tight-buffered and jacketed. Simplex cables are most often used where only a single transmit and/or receive line is required between devices or when a multiplex data signal is used. While duplex cables are most often applied in duplex communication between devices where a separate transmit and receive are required.

PVC vs. LSZH cables

PVC and LSZH cables are the third pair of fiber optic cables. PVC (Poly Vinyl Chloride) cables have a jacket that gives off heavy black smoke, hydrochloric acid, and other toxic gases when it burns. There are many types of fiber optic patch cables with PVC jacket. LSZH (Low Smoke Zero Halogen) cables have a flame-resistant jacket that doesn’t emit toxic fumes even if it burns. Physically, PVC and LSZH cables are very different. PVC cables are very soft, while LSZH cables are more rigid because they contain the flame retardant compounds and they are aesthetically more pleasing. LSZH cables usually cost more than the equivalent PVC cables. As for the applications, PVC cables are commonly used for horizontal runs from the wiring center. You can use them for vertical runs between the floors only if the building features a contained ventilation system running through the duct work. While LSZH cables are used between floors in a building.

Distribution-Style vs. Breakout-Style Cables

The last pair of fiber optic cables are distribution-style and breakout-style cables. Distribution-style cables have several tight-buffered fibers bundled under the same jacket with Kevlar or fiberglass rod reinforcement. These cables are small in size, which are used for short, dry conduit runs in either riser or plenum applications. While breakout-style cables are made of several simplex cables bundled together, making them strong and larger than distribution cables. These cables are suitable for conduit runs and riser and plenum applications. The following picture shows the difference between distribution-style and breakout-style cables.

Distribution-Style vs. Breakout-Style Cables


Fiber optic cables offer a number of advantages, such as great bandwidth, high speed and long distance, reliable security, etc. The above four pairs of fiber optic cables all have their unique characteristics and applications. Actually, there are more fiber optic cable types except the above four pairs of cables, like indoor and outdoor cables, loose-tube and tight-buffered cables, etc. By learning the differences of different optic cables, you can make a wiser choice.

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