Currently, there are four commonly used data transmission bits per second (unit: bps): 155Mbps, 1. Transfer rates are generally backward compatible. Single-mode fiber optic cables single-mode fiber optic cables 1 have a small core, typically around 9µm, and are designed to carry signals over long distances at higher bandwidths. They feature low attenuation benchmarks 2 and minimal dispersion. They use OS1 or OS2 OS1 or OS2 classifications to. This document outlines the specifications for a single-mode optical fiber and cable designed for use around the 1310 nm zero-dispersion wavelength, suitable for both the 1310 nm and 1550 nm regions, and compatible with analogue and digital transmission. It typically operates at wavelengths of 1310-1550 nm.