Archived — Fiber Optic Technology

Overview With the fiber optics revolution for telecommunications in the 1980s, fiber optical technology became increasingly more advanced and higher quality. The telecommunications boom in the late 1990’s resulted in a dramatic boost to the technical capability of fiber optical technologies and associated optoelectronics. Radical improvements were made in superb quality, very long lifetime, and reduced price for many components: pump diode lasers, coupling, beam combiners, rotators, Bragg fiber filters, modulators, and detectors. Also, the fibers themselves have seen significant innovation over the last decade, with commercial availability of larger cores for higher power, double-clad fibers for multimode pumping, producing

Pulse Spreading The data which is carried in an optical fiber consists of pulses of light energy following each other rapidly. There is a limit to the highest frequency, i.e. how many pulses per second which can be sent into a fiber and be expected to emerge intact at the other end. This is because of a phenomenon known as pulse spreading which limits the “Bandwidth” of  the fiber.The pulse sets off down the fiber with an nice square wave shape. As it travels along the fiber it gradually gets wider and the peak intensity decreases. Cause of Pulse Spreading

Reflection and Refraction of Light When light travelling in a transparent material meets the surface of another transparent material two things happen 1. some of the light is reflected 2. some of the light is transmitted into the second transparent material The light which is transmitted usually changes direction when it enters the second material. This bending of light is called refraction and it depends upon the fact that light travels at one speed in one material and at a different speed in a different material. As a result each material has its own Refractive Index which we use to

Definition Fusion splicing is a technique to join two fibers ends. Optical power loss at the splicing point is known as splice loss. How splice loss can be measured? An Optical Time Domain Reflectometer (OTDR) can be used for splice loss measurement. A cable section-containing splices are normally shown as knees on the optical power loss OTDR graph. As per the procedure (ANSI/TIA/EIA-455-8-2000), splice loss measurements with an OTDR must be conducted from both directions and averaged (by adding with signs)for accurate splice loss. Below is the graphical picture of ‘gainers’ and ‘exaggerated losses’ measurements; the effect on actual splice

4. Testing And Troubleshooting Communications Equipment After the cable plant has been tested, the communications equipment should be properly connected using matching known-good patch cords. If the cable plant loss is within the loss budget of the equipment (including the loss of the patch cords), the communications link should work properly. If the link does not work, most likely potential problems are the following. a. Improper connections b. Cable plant problems c. Malfunctions of communications equipment 4.1. Testing And Troubleshooting Steps For Communications Equipment a. Improper connections. The system requires a transmitter be connected to a receiver, of course, so