cisco - o 'Introduction to Optical Fibers, dB, Attenuation and Measurements' - adresa:
1.
http://www.cisco.com/en/US/tech/tk482/tk876/technologies_tech_note09186a008011b406.shtml#con1

2.
http://www.cisco.com/en/US/products/hw/optical/ps2006/products_tech_note09186a00800e6eeb.shtml