Over the past few years, fiber optic cable has become more affordable and widely used. Fiber is ideal for high data-rate systems such as FDDI, multimedia, ATM, or any other network that requires the transfer of large, time-consuming data files. And the basic cables are multimode optic cables and single mode cables.

A Comparison Of Multimode Cables And Single Mode Cables

Multimode cables have a larger core diameter than that of singlemode cables. This larger core diameter allows multiple pathways and several wavelengths of light to be transmitted. Singlemode Duplex cables and Singlemode Simplex cables have a smaller core diameter and only allow a single wavelength and pathway for light to travel. Multimode fiber is commonly used in patch cable applications such as fiber to the desktop or patch panel to equipment. Multimode fiber is available in two sizes, 50 micron and 62.5 micron. Singlemode fiber is typically used in network connections over long lengths and is available in a core diameter of 9 microns (8.3 microns to be exact).

Most building cables had 62.5/125 micron multimode fibers for LANs or security systems, while outside plant cables were all single-mode fiber. For some time, we have been encouraging people to install hybrid cables with both multimode fibers for today and single-mode fibers for the future regardless of the fiber optic cable price.

If you are transmitting from a smaller fiber core to a larger one, it is not a problem since the larger fiber like large core optical fiber will collect all the light from the smaller one with minimal loss. But if you transmit light from a larger fiber to a smaller one, the light in the larger core will overfill the smaller core and large losses will occur. How big are the losses we are talking about? Coupling a multimode fiber to a single-mode fiber will cause about 20 dB loss. Connecting a 62.5 fiber to a 50 micron core fiber will cause 2 to 4 dB loss, depending on the type of source (laser or LED). In any case, it can be enough loss to prevent network equipment from working properly.

Both 50 micron and 62.5 micron multimode fibers have the same cladding diameter and can use the same connectors and termination processes, but testing still requires using the correct matching fiber optics patch cords or the measured loss will be too low by a few tenths of a dB in one direction (50 to 62.5), or 2 to 4 dB too high the other way (62.5 to 50.)

Needless to say, these mismatched fiber losses affect the end user the same way they affect the installer, creating excess connection loss that can cause systems to malfunction or have high error rates, causing an expensive and annoying service call. Unfortunately, there is no optical mating adapter that will match two dissimilar fibers—although it has been tried many times. There is no solution other than preventing mismatched fiber terminations.

Fiber optics has high bandwidth and can transmit data over longer distances. Turn to buy fiber optic cable, you may confused as  there are so many types of cables and it's difficult to  figure them out. An optical fiber cable consists of a center glass core surrounded by several layers of protective material. The outer insulating jacket is to prevent interference. The construction design and choices of materials are vital in determining characteristics of a cable. The design factors for some types of fiber optic cables are listed below.

Indoor cables- Fire safety is the number one factor in selecting indoor cables, particularly those that run through plenum spaces. Indoor cables must pass the flame-retardant and smoke-inhibitor ratings specified by NEC.

Outdoor cables- Moisture resistance and temperature tolerance are the major factors when choosing materials for outdoor environment cables, like waterproof cables and outdoor cables do. They also need to be ultraviolet (UV) resistant.

Aerial/Figure 8 Self-Supporting Cables- Aerial cables must endure extreme temperature ranges from sunlight heat to freezing snow. They also must survive high wind loading.

Cable Jacket Materials

Polyethylene (PE). PE (black color) is the standard jacket material for outdoor fiber optic cables. PE has excellent moisture – and weather-resistance properties. It has very stable dielectric properties over a wide temperature range. It is also abrasion-resistant.

Polyvinyl Chloride (PVC). PVC is the most common material for indoor cables, however it can also be used for outdoor cables. It is flexible and fire-retardant. PVC is more expensive than PE.

Polyvinyl difluoride (PVDF). PVDF is used for plenum cables because it has better fire-retardant properties than PE and produces little smoke.

Low Smoke Zero Halogen (LSZH) plastics. LSZH plastics are used for a special kind of cable called LSZH cables. They produce little smoke and no toxic halogen compounds. But they are the most expensive jacket material.

Typical fiber cables are made from silica glass, which causes refractions that delay the signal. The standard line is that fiber optic networks transfer data at the speed of light. But in reality, light travels about 31 percent slower through fiber optical cables than it does through a vacuum. But that’s changing, researchers at University of Southampton in England have found a way to build cables that work at 99.7 percent of the speed of light in a vacuum. The researchers' solution — is a hollow cable with special walls to prevent refraction. They call it an "ultra-thin photonic-bandgap rim".

Several recent breakthroughs in fiber optics research. For example, scientists at AT&T Labs-Research announced a new record in speed/distance through standard bulk fiber optic cable. And a DARPA-backed team at IBM has found a way to cut the energy use of short-distance fiber optics for supercomputing while doubling the speed.

Fiber optic cables are designed for long distance and high bandwidth (Gigabit speed) network communications. Bulk fiber optic cables carry communication signals using pulses of light. While relative expensive, these cables are increasingly being used instead of traditional copper cables, because fiber offers more capacity and is less susceptible to electrical interference. So-called Fiber to the Home (FTTH) installations are becoming more common as a way to bring ultra high speed Internet service (100 Mbps and higher) to residences.

Copper cabling uses electricity to transmit signals from one end to another, bulk fiber optic cable uses light pulses to accomplish the same purpose. The fiber optic cable is made of a transparent glass core surrounded by a mirror like covering called cladding. Light passes through the fiber optic cable, bouncing off the cladding until it reaches the other end of the fiber channel - this is called total internal reflection. As fiber-optics are based entirely on beams of light, they are less susceptible to noise and interference than than other data-transfer mediums such as copper wires or telephone lines. In today's high speed networks, Graded Index Multimode fiber or Step Index Single mode fiber cable is used to improve light transmission over long distances. Multimode fiber optic cable has a larger core like large core fiber and is typically used in short runs within buildings. Single mode fiber optic cable has a smaller core and is used in long distance runs typically outside between buildings.

While fiber optic cables have so many advantages and widely used in today's communication. You should take in mind that fiber optic cables are fragile. Fiber cable can be pulled with much greater force than copper wire if you pull it correctly. Just remember following rules:

Do not pull on the fibers. The fiber optic cable manufacturers give you the perfect solution to pulling the cables, they install special strength members, usually Kevlar cutter or a fiberglass rod to pull on. Use it! Any other method may put stress on the fibers and harm them. Most cables cannot be pulled by the jacket. Do not pull on the jacket unless it is specifically approved by the cable manufacturers and you use an approved cable grip.

Do not exceed the maximum pulling load rating. On long runs, use proper lubricants and make sure they are compatible with the cable jacket. On really long runs, pull from the middle out to both ends. If possible, use an automated puller with tension control or at least a breakaway pulling eye.

Do not exceed the cable bend radius. Fiber is stronger than steel when you pull it straight, but it breaks easily when bent too tightly. These will harm the fibers, maybe immediately, maybe not for a few years, but you will harm them and the cable must be removed and thrown away!

Do not twist the cable. Putting a twist in the cable can stress the fibers too. Always roll the cable off the spool instead of spinning it off the spool end. This will put a twist in the cable for every turn on the spool! And always use a swivel pulling eye because pulling tension will cause twisting forces on the cable.

Check the length. Make sure the cable is long enough for the run. It's not easly or cheap to splice fiber and it needs special protection. Try to make it in one pull, possible up to about 2-3 miles.

A fiber optic patchcord is fiber optic cable capped at either end with connectors that allow it to be rapidly and conveniently connected to CATV, an optical switch or other telecommunication equipment. Its thick layer of protection is used to connect the optical transmitter, receiver, and the terminal box. This is known as "interconnect-style cabling".

A fiber optic patch cord is constructed from a core with a high refractive index, surrounded by a coating with a low refractive index that is surrounded by a protective jacket. Transparency of the core permits transmission of optic signals with little loss over great distances. The coating's low refractive index reflects light back into the core, minimizing signal loss. The protective jacket minimizes physical damage to the core and coating.

Patch cords are classified by connector construction and by construction of the connector's inserted core cover.

Connector Construction
Connector design standards include FC, SC, ST, LC, MTRJ, MPO, MU, SMA, FDDI, E2000, DIN4, and D4. Cables are classified by the connectors on either end of the cable; some of the most common cable configurations include FC-FC, FC-SC, FC-LC, FC-ST, LC-SC fiber patch cable, LC LC patch cable, SC-SC patch cord, and ST connectors fiber.

Inserted Core Cover
The connector's inserted core cover conforms to APC, UPC, or PC configuration. A UPC inserted core cover is flat and is used in SARFT and early CATV. An APC connector's inserted core cover is oblique (about 30 °, ±5 °).

Patch cables are used for connections to CATV (Cable Television), telecommunication networks, computer fiber networks and fiber test equipment. Applications include communication rooms, FTTH (Fiber to The Home), LAN (Local Area Network), FOS (fiber optic sensor), Fiber Optic Communication System, Optical fiber connected and transmitted equipment, Defense combat readiness, etc.

FiberStore's commitment to providing unsurpassed technical service and support has gained the loyalty and favor of customers worldwide. We work exclusively through the industry's leading distributors to provide custom manufacturing of fiber optic and copper cable assemblies, as well as distribution of a wide range of products ranging from simple to complex, standard to custom.

Order information:
Fiber connector 1: FC and FC/APC,ST,SC and SC/APC,LC,MU,MTRJ,SMA,DIN,MPO,E2000
Fiber connector 2: FC and FC/APC,ST,SC and SC/APC,LC,MU,MTRJ,SMA,DIN,MPO,E2000
Ferrule Interface type: UPC, APC
Fiber cores: Simplex fiber core ,duplex fiber core
Fiber type: Singlemode(G. 652, G655), multimode(50/125)/(62.5/125),OM3
Fiber Cable Size: 250um bare fiber, 900um tight buffer fiber, 1.6mm fiber optic cable, 2.0mm fiber optic cable, 3.0mm fiber optic cable
Cable length: custom
Special types of fiber optic patch cables: Volition Fiber Patch Cables,Military Grade Fiber cable,Pre-Terminated Fiber cable,Fiber Loopback Cables,Plastic Optical Fiber Patch Cables,FTTH Patch Cables,Polarization Maintaining Patch Cables,Mode Conditioning Patch Cables,etc.

In any fiber optic cable installation, the way the cables are attached to the system--is vital to the success of the telecommunications network. If done well, the connection allows optical signals to pass with low attenuation and little return loss. One of the proven ways to join optical fibers is with a fiber pigtail--a fiber cable with a installed connector on one end and unterminated fiber on the other end.

Pigtails are basically cable assemblies. Ninety-nine percent of singlemode applications use pigtails, also used in many multimode applications. One of the benefits of using pigtail is lower labor costs. The end of the pigtail is stripped back and fusion spliced to another single fiber. This is done easy in field with a multi-fiber trunk to break out the multi-fibers cable into its component for connection to the end equipment. Installers working with singlemode fiber typically have access to a fusion splicer--an expensive piece of equipment that costs $6000 to $30,000 or more. With a fusion splicer you just splice the pigtail right onto the cable in a minute or less.

Pigtails bridge a critical junction in the fiber-optic network. Pigtails consist of--a connector, a ferrule, standard fiber and jacket types, including singlemode and multimode varieties. The most important element you should know is that the quality of the connector itself. You need to know certain characteristics, such as insertion loss, the type of polish used and how well the connector is terminated to the cable. As fiber cable termination is the addition of connectors to each optical fiber in a cable. The fibers need to have connectors fitted before they can attach to other equipment. Two common solutions for fiber cable termination are pigtails and fanout kits or breakout kits.

Ferrule material, whether zirconia ceramic, plastic or stainless steel, must also be specified when buying a pigtail. If you go with a metal ferrule, it is a waste for any singlemode application.

The length of the pigtail is another element that must be specified. The extra slack allows for splicing errors to be corrected, without it, you may have to start with another pigtail.

Pigtails can have female connectors and be mounted in a wall mount or patch panel, often in pairs although single-fiber solutions exist, to allow them to be connected to endpoints or other fiber runs with patch cables. Alternatively they can have male connectors and plug directly into an optical device. Pigtails are different from patch cords, as both ends with connectors, like common patch cord LC-LC.

Testing a pigtail in the field is not easy. The unterminated end is difficult to check until the pigtail is actually spliced to the equipment.
Quality is typically high because the connectorized end is attached in a controlled environment--FiberStore. FiberStore can make singlemode pigtails more accurately than a field termination can be done.