Silica Optical Fiber Technology for Devices and Components: Design, Fabrication, and International Standards

CHAPTER FIVE

Multimode Fibers for Large-Bandwidth Applications

5.1 HISTORY AND RECENT APPLICATION TRENDS OF MULTIMODE OPTICAL FIBERS

In comparison to single mode fibers’ (SMFs) dynamic, rapid, and variegated development, multimode optical fibers (MMFs) have shown three distinctive evolution steps in the past three decades, from a step index (SI) MMF to graded index (GI) MMF and then toward most recent laser optimized (LO) MMF as shown in Figure 1.2. This MMF development is closely related with demands in optical networks where they use different data rates, link distances, and light sources in order to take fullest advantage of MMFs’ easy connection to economic light sources and detectors.

MMF applications include fiber distributed data interface (FDDI) or Ethernet-based local area network (LAN) [1,2], fiber channel (FC)–based storage area network (SAN) [3], and synchronous digital hierarchy (SDH)–based very-short-reach (VSR) networks [4]. Recently MMFs furthermore expanded applications in digital image communication (DICOM)–based picture archiving communication systems (PACS) [5] and media-oriented system transport (MOST)–based automobile intranet-work [6]. These various short-haul optical systems require ever-increasing transmission capacity as in the case of long-haul applications, and intensive efforts have been focused on development of high-bandwidth MMF in terms of material choice, waveguide structure optimization, and reliable characterization methods (Figure 5.1).

The ...