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.