Fiber optics

Abstract

This chapter is focused on practical handling of standard optical fiber cables. The first section introduces basics of total internal reflection, concept of numerical aperture, structure of standard optical cables and their specifications. Dimensions and thread type of SMA connectors are summarized as a reference for manufacturing as well as some practical ideas for connecting SMA cables to handmade opto-electronic equipment. Difference in jacketing is outlined to facilitate right choice. Various standard opto-couplers that can be found on the market are recommended with detailed dimensional specifications of connecting threads. Correct and incorrect connectivity options are explained and summarized in a comprehensive drawing. Spectral transmission of optical fibers may be crucial for ultra-violet applications below 400 nm. Some typical spectral curves show the lower spectral limit where special considerations must be applied. Advantages and disadvantages of plastic optical fibers are summarized and standard connectors explained in a detailed figure. Physics of polarization-maintaining optical fibers of the two standard types is explained in general phenomenology. Multi-fiber bundles are used either for illumination purposes, as it is briefly outlined in the second section, or as imaging elements—rather complicated and expensive optical elements described in the last section. Imaging optical fibers are rather rare, and wide audience does not commonly know their imaging capabilities. Therefore, details of the design and experimental high-magnification images may be useful for understanding performance of these optical elements.