652 describes the geometrical, mechanical and transmission attributes of a single-mode optical fibre and cable which has zero-dispersion wavelength around 1310 nm. All three fiber types are characterized as “ low‑water peak ”, meaning the maximum attenuation requirement at 1383 nm is equivalent to the maximum attenuation specified at 1310 nm. This constraint eliminates the concern that the fiber will have high loss in the 1360 nm to 1460 nm band caused by OH. The International Telecommunication Union (ITU) has been continuously improving the industry standards for OS2 optical fiber, evolving from G. These modes define the way the wave travels through space, i.