Obere mmiri kacha elu na-abụghị dispersive otu-mode eriri kwesịrị ekwesị maka nnyefe usoro nke zuru band 1280nm ~ 1625nm, nke ọ bụghị nanị na-ejigide ala dispersion nke omenala band 1310nm, ma nwekwara a ala ọnwụ na 1383nm, na-eme ka E band. (1360nm ~ 1460nm) ejiri ya n'ụzọ zuru oke. Ọnwụ na mgbasa nke ìgwè ahụ dum sitere na 1260nm ruo 1625nm na-eme ka ọ dịkwuo mma, na nkwụsị nkwụsị nke 1625nm wavelength na-ebelata, nke na-enye ihe onwunwe bandwidth maka netwọk azụ, MAN na ịnweta netwọk.