Propagation Studies of 40 km of Graded-Index Fiber Installed in Cable in an Operational Duct Route

Forty kilometers of graded-index fiber has been installed in cables in duct running from the Post Office Research Center. Its loss and bandwidth have been measured in detail and the extrapolation of both studied as a function of link length. The links are characterized by low loss averaging 4.33 dB/km including joints and by large bandwidth. A number of new effects have been identified and explained during the course of the bandwidth studies.