Freezing temperatures can cause the ground to shift, leading to microbending and macrobending in buried fiber optic cables. Microbends and Macrobends What Happens Microbends are small-scale distortions in the fiber core caused by uneven pressure or tightly packed fibers. Macrobends are. To determine the power budget and power margin needed for fiber-optic connections, you need to understand how signal loss, attenuation, and dispersion affect transmission. Multimode fiber is large. Fiber loss, also called fiber optic attenuation or attenuation loss, refers to the loss of signal between input and output. There are various possibilities: Mechanical splicing means that two fiber ends are tightly held together with some mechanical means. In practice, however, attenuation is not constant.