Final answer:
Monomode fibers are used in optical communications for their low loss, high bandwidth, and reduced crosstalk, maintaining signal integrity and quality over long distances.
Step-by-step explanation:
We use monomode fibers in optical fiber communications because they offer several significant advantages, especially for long-distance transmission. These include low loss, where the fibers are so transparent that light can travel for many kilometers without substantial dimming; high bandwidth, allowing for a higher number of conversations or data transmissions simultaneously; and reduced crosstalk, where optical signals in one fiber do not interfere with signals in adjacent fibers.
The fibers are constructed with a core and a surrounding cladding material that has a lower index of refraction. The total internal reflection within the core keeps the light signals confined, preventing loss of signal and maintaining high-quality transmission. The cladding not only preserves signal integrity by preventing light from escaping but also adds to the durability and flexibility of the fiber.