Measuring Attenuation In Embedded Optical Fiber

摘要

I he use of embedded optical fiber printed circuit boards is a growing phenomenon, one that has many implications for PCB designers and engineers. When optical fiber is embedded in a PCB, its optical attenuation becomes the primary concern, mainly due to material, geometry and layout considerations. Once you've selected the fiber, the material properties and cross-section are determined. Of course, in addition to material geometry and layout, there are many other considerations that affect the attenuation of the embedded optical fiber. These include the choice of single mode vs. multimode, laser, numerical aperture, bits per second and modulation. Usually, these are decided as systematic requirements before the fiber is to be laid out for a PCB. Unlike the layout of the electrical interconnection, layout of the optical wave guide is largely sensitive to both the horizontal and vertical curvatures. The former is also affected in the microwave frequencies. This article will discuss the attenuation of the optical fiber due to both horizontal and vertical bends, which is the key concern for the integration of optical fiber into a PCB optical network. We will focus on the integration of the optical fiber into a PCB and the relationship between the attenuation and layout from the viewpoint of the PCB designer.