This enhanced Singlemode fiber provides improved performance across the entire 1260 nm to 1625 nm wavelength spectrum due to its low attenuation in 1383 nm the water-peak region. The fiber design is matched cladding. A1 The older ITU designations A, B. There are 19 different single mode optical fiber specifications defined by the ITU-T, among which G. 652D optical fiber, often referred to as low-water peak single-mode fiber, is the latest and most advanced variant of the standard G. 1dBNote: Due to OTDR measurement uncertainty B3 International cannot guarantee attenuation values at fibres shorter than 1000m. Parameters are subject to change without notice. ro Dispersion Wavelength Zero Dispersion Slope Typical Value 131.