Copper cable is still used in many data centers, but over the last few years, many data centers have made the switch to optical fiber cables. Optic fiber cabling is categorised into single-mode fiber and multi-mode fiber. Single-mode fiber is costlier than multi-mode fiber, but there are other factors involved apart from the price which have to be considered as well, before you make a decision on which cabling system to procure for your data centre. By this, we mean factors such as attenuation. What is attenuation? Attenuation refers to the higher weakness of fiber optic signals as the distance covered by the cable increases. This is what one called dB loss. Single-mode fiber cables suffer a much higher dB loss compared to multi-mode fiber, which explains why they are much pricier. Single-mode fiber cables perform better because their fiber cores are only 9 mm in diameter. This means the light that passed through these cables is not reflected too many times, which keeps the attenuation to a minimum. So you can use the single-mode fiber for long range connections and for applications that require higher speeds. Multi-mode fiber cables have a 50 mm or 62.5 mm diameter. The attenuation suffered by the light that passes through these cables is kept to a minimum at short distances, but increases over long distances. That’s because the core has a bigger diameter, and this leads to more light reflections. The wavelength is another important factor to be considered when you are choosing between a single-mode fiber and a multi-mode fiber.