There are two basic categoies of fiber optic cables due to the different fiber optics cores of the optical fiber, which are singlemode/multimode and simplex/duplex.
Singlemode Fiber Optic Cable
Singlemode fiber has a small core and just one path for light to travel down. Since there is only one wavelength of light moving through the core, single mode light aligns at the center of the optic core rather than bouncing about the interior of the core, which is the technology that enables multimode cable to carry multiple light signals. With only a single wavelength of light passing through its core, singlemode fiber optic cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as with multimode. Singlemode fiber optic cable is typically used in long-haul network connections spread out over extended areas (longer than a few miles). For example, telcos use it for connections between switching offices. Singlemode fiber optic cable features a 9-micron glass core.
Multimode Fiber Optic Cable
Multimode fiber has a large diameter fiber core. Due to its relatively large size, multiple channels of light can be transmitted, allowing multiple bandwidths and signals to be transmitted simultaneously. Multimode works great for most fiber applications. It works especially well in alarm systems, audio/video systems and production, desktops and laptops, and display systems. Multimode fiber optic cable has a large-diameter core that is much larger than the wavelength of light transmitted, and therefore has multiple pathways of light-several wavelengths of light are used in the fiber core. Multimode fiber optic cable can be used for most general fiber applications. Multimode fiber optic cable is used for bringing fiber to the desktop, for adding segments to your existing network, or in smaller applications such as alarm systems. It comes with two different core sizes which are 50 micron or 62.5 micron.
Simplex Fiber Optic Cable
Simplex fiber optic cables consist of just one optical fiber. Analog to digital data readouts, interstate highway sensor relays, and automated speed and boundary sensors (for sports applications) are all great uses of simplex fiber optic cables. This form of fiber optic cable can be cheaper than duplex fiber optic cables, because less material is involved. Simplex fiber optic cable consists of a single fiber, and is used in applications that only require one-way data transfer. For instance, an interstate trucking scale that sends the weight of the truck to a monitoring station or an oil line monitor that sends data about oil flow to a central location. Simplex fiber optic cable is available in singlemode and multimode.
Duplex Fiber Optic Cable
Duplex fiber optic cable is simply two optic fibers structured in a zipcord arrangement. Zipcord style means the cables run next to each other. Multimode and singlemode duplex fiber alike are used for two-way data transfers. Larger workstations, optical switches, network servers, and major networking hardware tends to require duplex fiber optic cables. Duplex fiber optic cables can be more expensive than simplex fiber optic cables, and are compatible with any extender. Duplex cable consists of two fibers, usually in a zipcord (side-by-side) style. Use duplex multimode or singlemode fiber optic cable for applications that require simultaneous, bi-directional data transfer. Duplex fiber optic cable is available in singlemode and multimode.