Definitions of common terms related to fibre optics, including SDH, PDH, SONET, DWDM, FTTH, and more. Learn the basics of optical communication. Fiber optic communication is a cornerstone of modern telecommunications, encompassing a wide array of technical terms and concepts. These terms form the technical language behind how data is transmitted. This article will explain the top 100 most commonly used fiber optic terms and acronyms, offering a foundational understanding of the subject. Made from high-quality glass. All-fiber access network. Used primarily in cable TV (CATV) market. A cone angled area that light must enter in order to "bounce" down the fiber and remain in the core of the fiber.