71.   The operation is helping Pacific Bell build an advanced fiber network that will carry telephone programming over phone lines.

72.   The need for such regeneration adds cost and complexity to the construction and operation of continent-spanning fiber optic networks.

73.   Their excitement, however, is tempered by fear that the Bells may abandon these technologies once their fiber networks are in place.

74.   Then there are optical service providers like IntelliSpace, which sells broadband services to businesses through its own fiber optic networks.

75.   There are many reasons to believe that the vast new fiber optic network will similarly call forth unforeseen new applications.

76.   The wireless links could also be used to connect with commercial Internet service providers who bring high-speed fiber optic networks that pass in front of buildings.

77.   The write-down by Verizon would be another example of how the rapid expansion of fiber optic networks in the last few years created a glut of capacity.

78.   This is done to feed huge multimedia files over fiber optic networks that have a finite transmission capacity.

79.   This time, the sensors, modified versions of devices normally used in fiber optic networks, showed that the device was producing single photons.

80.   TyCom builds underwater fiber optic networks for communications companies, and has spent billions of dollars on its own network.