Is the internal fiber optic cable single-mode or multi-mode

Indoor fiber optic cables are typically multi-mode, designed for short-distance, high-speed data transmission within buildings.Key Characteristics of Indoor FiberMulti-mode fiber is most commonly used for indoor installations because it has a larger core diameter (usually 50 µm or 62.5 µm), allowing multiple light modes to propagate simultaneously. This makes it ideal for short-distance connections, such as within offices, data centers, or between floors of a building, where high bandwidth is needed but long-distance transmission is not required . Multi-mode fibers are often labeled as OM1, OM2, OM3, OM4, or OM5, with higher OM numbers supporting faster speeds and longer distances within the building . Single-mode fiber, in contrast, has a much smaller core (around 8–10 µm) and allows only a single light mode to travel. This reduces signal loss and modal dispersion, making single-mode fiber suitable for long-distance applications, such as between buildings or across campuses, but it is generally more expensive and less common for indoor cabling .Practical ConsiderationsDistance: Multi-mode fiber is preferred for indoor runs typically under 500 meters, while single-mode is used for longer distances.Cost: Multi-mode fiber and its transceivers are usually less expensive than single-mode solutions.Light Source: Multi-mode fiber often uses LED or VCSEL light sources at 850 nm, whereas single-mode fiber uses laser sources at 1310 nm or 1550 nm .Installation: Indoor multi-mode cables are easier to terminate and handle due to their larger core and flexibility. In summary, most indoor fiber optic cables are multi-mode because they are optimized for short-distance, high-bandwidth applications within buildings, while single-mode fiber is reserved for long-distance or backbone connections .