- Fiber Optic Cable Definition: A fiber optic cable is defined as a network cable made up of strands of glass fibers that use light to transmit data over long distances.
- Transmission Efficiency: These cables are superior to traditional copper cables as they can transmit data over longer distances with higher bandwidth and without electromagnetic interference.
- Cable Types: There are primarily two types of fiber optic cables: single-mode for long-range communication and multimode for medium-range.
- Use Cases: Fiber optic cables are crucial for high-performance data networking and telecommunications, benefiting industries requiring high-speed data transfer.
- Physical Construction: The core components of these cables include the core, cladding, and coating, each contributing to efficient and secure data transmission.
What are Fiber Optics Cables Used For?
Fiber optic cables (also known as optical fiber cable) are network cables that contain strands of glass or plastic optical fibers. The two main types are single-mode for long-haul links and multimode for shorter indoor or campus runs in data networking and telecommunications. Signals travel as pulses of light in the fibers, not as copper current.
Compared with copper pairs, fiber can carry a higher bandwidth over a longer reach. Single-mode is the long-distance type. Multimode is the shorter-reach type used inside buildings and campuses.
Plant cost is often higher than copper at first install. Fewer repeaters on long runs can cut later upkeep, but that is a route design result, not a rule that fiber always costs less to keep.
Glass does not carry line current, so I²R heating in the core does not apply. The optical path is immune to EMI and RFI. Armour or nearby metal can still pick up fields. Optical connectors and splices remain part of the plant. The copper wire connectors used on metallic pairs are a different product.
Choosing a fiber is easier once the mode, core size, jacket colour and connector type are named. Those facts also matter because the cable and the install labour are both costly.
The rest of this page names the cable types, the usual jacket colours and the core, cladding and coating.
The two main types of fiber optic cables are single mode (or mono-mode) fiber optic cable or multimode fiber optic cables.
Fiber Optic Cable Types
Single Mode Fiber (Mono-Mode)
Single-mode fiber cables use a small glass core, typically about 8 to 10 μm (often quoted as 8.3 to 10 microns). That narrow core supports one guided mode. Plant wavelengths are usually 1310 nm or 1550 nm, with other bands used on some systems.
Over long routes, single-mode can carry a higher bandwidth than a multi-mode cable. Both types still need a matching light source, such as a laser or LED transmitter.
Single-mode plant and transceivers often cost more. The core is smaller. Modal dispersion is not the limiter the way it is in multimode.
Single-mode reach is typically tens of kilometres. Indoor multimode is typically metres to a couple of kilometres. There is no fixed “50 times” rule.
Multimode Fiber Optic Cable
Multimode Fiber Optic Cable uses a larger core, 50 μm or 62.5 μm. Reach depends on OM grade and bit rate. OM1 is about 275 m at 1 Gbit/s. OM3 and OM4 support 10 Gbit/s over a few hundred metres. Campus multimode is typically under 2 km. A duplex link uses two fibers for send and return. That does not make the glass core larger.
On a longer multimode run, many modes arrive at different times. That modal dispersion closes the eye and limits bit rate and length.
Fiber Patch Cord
A fiber patch cord (also known as the fiber patch cable or the optical jumper) is a short indoor assembly used in server rooms and data centres to join equipment and panels.
It is a length of fiber that ends with fiber optic connectors connected at each end. Those connectors mate to a switch, transceiver or panel.
Single-mode cables are known as OS1 and OS2. Indoor jackets are usually yellow. Multi-mode OM1 and OM2 are usually orange. OM3 and OM4 are usually aqua. Some vendors use Erika violet for OM4. OM5 indoor jackets are lime green in TIA-598.
Some makers use a blue jacket for polarization-maintaining patch cords. That is a vendor habit, not a rule in every plant.
An SMF patch cord (single-mode fiber) has a core diameter of about 8-10 µm. One guided mode is what that size is for. Bit rate still depends on the transceivers and the fiber grade, not on forcing light into the core.
Basic Elements of Modes Cable
There are three basic elements of a fiber optic cable:
- Core: Starting with the core, it is the area light transmission that occurs in the fiber, being either glass or plastic. A larger core accepts more modes, which is why multimode cores are larger than single-mode cores.
- Cladding: It is used to provide a reflection within the core of the cable, this will help the light waves transmit through the fiber.
- Coating: Like any other coating, it is used to be multi-layers on the cables to help preserve the strength of the fiber, as well as absorb shock and extra fiber protections needed.
The coats come in various amounts from 250 microns to 900 microns.
The two mode families remain single-mode and multimode. Jacket colour and core size are how plants tell them apart on the bench.
Yellow, orange, aqua, violet and lime jackets are the usual indoor colour split described above.
