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What is Bend Insensitive Fiber
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=UkkrB-up2KA
http://www.fiberoptics4sale.com • http://www.fiberoptics4sale.com/wordp... • Conventional optical fibers are very sensitive to sharp bends. If you bend the fiber exceeding its minimum bending radius, light will escape from the fiber core, and causing significant power loss. • But in fiber to the home installations, as shown in this picture. Sharp bends are unavoidable. Not to mention careless technician skills. This makes it necessary to design optical fibers that can endure sharp bends and still show minimum power loss. • The trick that optical fiber manufacturers used is a refractive index trench around the fiber core, which is basically a ring of lower refractive index material. This ring can be seen in this lower picture. • In regular graded index multimode fiber, there are many modes travelling down the fiber. The inner modes are strongly guided which means they have little sensitivity to bending stresses. But the outer modes are weakly guided which means they can leak out of the core when the fiber is bent. • The lower refractive index ring literally reflects the weakly guided modes back into the core when stress normally causes them to be coupled into the cladding. • The trench is just an annular ring of lower index glass surrounding the core with very carefully designed geometry to maximize the effect. • When you look at the end of a bend-insensitive fiber in a microscope with angled lighting, you can sometimes actually see the trench as a gray ring around the core. • Currently there is no standard which defines tighter bend radius for multimode fibers. So all bend insensitive multimode fibers have to be compliant with existing conventional 50um multimode fibers such as OM2, OM3, and OM4. • ITU-T G.657 covers two categories of single mode bend insensitive fibers as Category A and Category B as listed here. • G.657 category A fiber conforms to the widely regarded G.652.D standard, while G.657 category B fiber does not. • Category A fibers will serve the majority of applications requiring a G.652.D fiber with improved bend performance. • Category B fibers can support unique or special tight bend applications, but with the added challenges of a non-standard fiber (splicing, reliability, higher cost, etc.). • So there you have it. Please leave your comment below if you'd like to see other topics. • Don't forget to visit http://www.fo4sale.com for more free fiber optic tutorials. I will see you in the next video!
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