Comparison of low-cost fiber optic technologies for data transmission

This paper presents a comparison of technologies for low-cost fiber-optic data transmission links. Previous authors have recognized the need for low-cost links. By contrast, there has been little written of the trade-offs in link cost/performance among the extant cost-effective fiber-optic technologies. A key cost reducing step can be made by employing large-core fiber (LCF) to allow less-precise alignment tolerances in the optical subassemblies (OSA) and connectors. The fiber-optics industry has recognized this and has responded by making available a myriad of LCF available to the link designer including glass and plastic step-index (SI) and graded index (GI) fibers in a range of diameters and numerical apertures. We will show, however, that the fiber choice and coupling optics design are constrained both by transmitter and receiver coupling efficiency and link bandwidth. The particular type of LCF will also determine the appropriate optical source wavelength, which can greatly impact link cost, bandwidth, and optical budget. Along with reducing the OSA cost, LCF also allows a reduction in connectorization cost and offers a link less susceptible to mode-selective loss noise. This study is summarized by a comparison of component costs, link budgets, and performance limits of both standard and low-cost fiber-optic technologies.