In electromagnetic media, repeate overcome the attenuation caused by free-space electromagnetic-field divergence or cable loss.
在电磁媒体中，重复克服衰减引起的空间电磁场散度或电缆损失。
2
The most typical weather restriction of Free-space Optical Communications System is the fog; the fog attenuation of laser is a main factor that affects the performance of the lasers communication.