Which type of fiber-optic cable provides the most stable transport characteristics and additional protection from stresses caused by macrobends and microbends?

Loose-tube cable is specifically designed to provide excellent protection and stability for fiber-optic fibers, especially in challenging environments. This type of cable consists of optical fibers that are housed in a protective tube that allows for movement within the tube. This design mitigates the effects of external stresses, such as macrobends (large-radius bends) and microbends (small-radius bends), which can negatively impact signal quality and transmission.

The loose-tube construction enables the fibers to expand and contract with temperature variations without putting stress on them, which is crucial for maintaining stable transport characteristics over time. Additionally, the buffer tubes can be filled with a protective gel or water-blocking materials that further enhance the cable's resistance to environmental factors such as moisture, ensuring a longer operational life and reliable performance.

In contrast, other types of cables like single-mode and multi-mode cables are designed for specific applications and may not provide the same level of protective features against external mechanical stresses. Armored cables do offer physical protection but are typically used to shield against impact and rodent damage rather than specifically addressing the bending stresses encountered in fiber-optic installations. Therefore, the advantages of the loose-tube design make it the best choice for stability under varying environmental conditions.