FROM MULTI-MODE FIBER TO SINGLE-MODE FIBER

FROM MULTI-MODE FIBER TO SINGLE-MODE FIBER
Multi-mode fiber was originally used as subscriber optical fiber. In 1988, NTT decided to
introduce single-mode fiber, which had originally been developed for trunk networks, into
the optical access network as well. This decision followed research into the best way to
introduce the fiber into the subscriber network [1].
The decision to go with the potentially more costly single-mode fiber in the subscriber
system, where cost considerations were paramount, was indeed a bold one, especially
considering that most other countries were considering multi-mode fiber for subscriber
systems. However, given the low-loss characteristics of single-mode fiber and its suitability
for broadband applications, it was definitely the correct decision for the future. The
introduction of single-mode fiber was made possible through the development of new
technology in a number of areas. In particular, these developments related to high-precision