16 Elliptical Core and D-Shape Fibers 513
Thomas D. Monte, Liming Wang, and Richard Dyott
16.1 Overview 513
16.1.1 Elliptical Core Optical Fiber 513
16.1.2 D-Shape Elliptical Core Fiber and Variations with
Assessable Regions 514
16.2 Manufacturing of Elliptical Core and D-Shape Fibers 515
16.3 Elliptical Core Fibers: Characteristics and Properties 517
16.3.1 Birefringence 519
16.3.2 Polarization Holding 520
16.3.3 Ellipticity and Higher Order Modes 520
16.4 D-Shape Fibers: Characteristics and Properties 521
16.4.1 Accessing the Optical Fields: Fiber Etching 522
16.4.2 Wet Etching of Silicon Dioxide–Based
Cladding and Germanosilicate Core 523
16.4.3 Standard Etching (Etch to Reach
Evanescent Field) 524
16.4.4 Exposing the Core 526
16.4.5 Partial and Full Core ...