Two fibers or one? (a comparison of two-fiber and one-fiber star architectures for fiber-to-the-home applications)

Issues for consideration when deciding between the two-fiber (2-F) and one-fiber (1-F) architectures for fiber deployment in the distribution portion of the loop are presented. A link-loss assessment of both architectures is presented. 1-F star transmission concerns, namely, directivity and wavelength isolation, are discussed. System upgrade of both architectures is considered. Testing and maintenance are addressed. A cost analysis is presented. The 2-F star is conceptually a simple architecture offering maximum upgrade potential and few transmission and testing concerns. However, its distribution link and life cycle costs exceed that of the 1-F star. The 1-F star offer potential cost savings in fiber cable, splicing, and long-term maintenance. The 1-F star has transmission concerns, however, that could impose limitations on the type of transceivers and other loop components being deployed, and this could result in higher system costs