Page 138 - Optical Switching And Networking Handbook

06_200023_CH05/Batesx 1/17/01 8:19 AM Page 123

Wave-Division and Dense-Wave-Division Multiplexing 123

Figure 5-8 140,000
Escalating costs
per mile to add 120,000
more fiber
100,000

in $ US 80,000
60,000

40,000

20,000

0
1996 1998 2000 2002

Cost of digging and adding more fiber per mile

Getting There from Here

Assuming that the carriers have been providing due diligence in
their efforts to meet and satisfy future demands, the following
choices are available:

Installing new fiber. As seen in the preceding section, this is
too expensive and daunting a challenge.
Investing in new TDM technologies to get faster rates
such as OC-192 and OC-768. This again involves getting a
fourfold increase for a large investment, but not the degree of
growth that we are looking for.
Using a combination of the TDM and DWDM
architectures to increase throughput by orders of
magnitude. This is the preferred method today. However, as
early as 1998-1999, many of the carriers were making
statements that they had sufficient fiber in the ground to enable
them to just activate (light up) a new fiber rather than invest in
new equipment. The old adage that “hindsight is better than