Final answer:
Single mode fiber optic systems use lasers as light sources due to their advantageous properties like low loss, high bandwidth, and reduced crosstalk for effective communication.
Step-by-step explanation:
Single mode fiber optic systems typically use lasers as light sources. This is because lasers emit light with characteristics that are highly suitable for optical communication systems.
These characteristics include low loss, allowing light to travel many kilometers before needing amplification, and high bandwidth, which permits a significantly greater number of conversations in one fiber compared to electric signals on a single conductor.
Additionally, lasers help in reducing crosstalk, where optical signals in one fiber do not produce undesirable effects in other adjacent fibers. The application of lasers in fiber optics takes advantage of the principle of total internal reflection to transmit light effectively through fibers of plastic or glass.