40 Gb/s over 590 km of in-ground fiber in a DWDM system

Bossnet is an in-ground testbed for developing optical networking techniques that enable new applications. The use of in-ground fiber (as opposed to laboratory experiments) allows new applications that require high data-rate communications over long distances to be tested. For the experiments described here, the light path includes ten spans of optical fiber with distances varying between 40 km and 73 km located on telephone poles and in the ground near railroad tracks and roadways. After each link, the light is amplified, filtered, and chromatic dispersion compensated. The experiment operates one 40-Gb/s RZ (return-to-zero format) channel at 193.5 THz and seven other channels with 10-Gb/s NRZ (non-return-to-zero format) modulation over a distance of 295 km from Lincoln Laboratory to New London, CT. These channels are dropped from the southbound fiber in New London and are added on the northbound fiber back to Lincoln Laboratory. This experimental arrangement allows the transmitter and receiver to be located in the same laboratory. A ninth channel, at 193.8 THz, carries Gigabit Ethernet traffic in both directions between Lincoln Laboratory and Washington, DC. Model calculations for the optical network produce eye diagrams in excellent agreement with the experimental results.