When light from a source is sent through a fiber-optic cable, the ligth wave both bounces around inside the cable and passes through the cable to the outlet protective jacket. When a light signal inside the cable bounces off the cable wall and back into the cable, this is called reflection. When a light signal passes from the core of the cable into the surrounding material, this is called refraction. Figure 3-9 demonstrates the differece between reflection and refraction.
Light can be transmitted through a fiber-optic cable using two basic techniques. The first technique, called single-mode transmission, requires the use of a very thin fiber-optic cable and a very focused light source, such as a laser. When a laser is fired down a narrow fiber, the light follows a tight beam, and so there is less tendency for the light wave to reflect or refract. Thus, this technique allows for a very fast signal with little signal degradation (and thus less noise) over long distances. Because lasers are used as the light source, single-mode transmission is a more expensive techique than the second fiber-optic cable signaling techique. Any application that involves a large amount of data transmitted at high speeds is a candidate for single-mode transmission.
The second signaling technique, called multimode transmission, uses a slightly thicker fiber cable and an unfocused light source, such as an LED. Because the light source is unfocused, the light wave experiences more refraction and reflection (i.e, noise) as it propagates through the wire. This noise results in signals that cannot travel as far or as fast as the signals generated with the single-mode technique. Correspondingly, multimode transmission is less expensive than single-mode transmission. Local area networks that employ fiber-optic cables often use multimode transmissions.
Single-mode and multimode transmission techniuqes use fiber-optic cable with different characteristics. The core of single-mode fiber-optic cable is 8.3 microns wide, and the material surrounding the fiber – the cladding – is 125 microns wide. Hence, single-mode fiber optic cable is labeled 8.3/15 cable. The core of multimode fiber optic cable is most commonly 62.5 microns wide, and the cladding is 125 microns. Multimode fiber optic cable is labeled 62.5/125 cable. Othe sizes of multimode fiber optic cable include 50/125 and 100/140 microns.
Bulk fiber optic cable comes in lots of types, depending on where it will be installed. Where to buy fiber optic cable? As the best OEM fiber optic cable manufacturer, Fiberstore provides a wide range of quality optical fiber cables with detailed specifications displayed for your convenient selecting. Per foot price of each fiber cable is flexible depending on the quantities of your order, making your cost of large order unexpected lower. Customers can also have the flexibility to custom the cable plant to best fit their needs. Only fiber cable that meets or exceeds industry standards is used to ensure quality products with best-in-class performance. Fiberstore offers an extensive line of off the shelf bulk fiber optic cable to address your fiber installation needs. We stock 62.5/125, 50/125, and 9/125 bulk fiber optic cable in simplex, duplex (zip cord), breakout, and distribution styles.
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