Specialty Optical Fibers Handbook

dispersion (PMD) is covered in Section 2.8. The phenomenology and theory of

microbending is the subject of Section 2.9, while fiber nonlinearity is briefly

introduced in Section 2.10.

2.2 PHYSICAL STRUCTURE OF A

TELECOMMUNICATIONS OPTICAL FIBER

Optical fibers are fabricated by first depositing high-purity silica soot, doped

with germania (GeO

2

) to raise the index of refraction or fluorine (F) to lower the

index of refraction, to form a core rod of 1 cm or more in diameter and 1 m or

more in length. Fabrication methods [1] include processes known in the industry

as ‘‘modified chemical vapor deposition’’ (MCVD) [2, 3], outside vapor depo-

sition (OVD) [4], vapor axial deposition (VAD) [5, 6], and plasma chemical

vapor deposition (PCVD) [7]. The MCVD,