  The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will
measure the expansion historyof the universe using the Baryon Acoustic
Oscillation technique. The spectra of 35 million galaxies and quasarsover 14000
sq deg will be measured during the life of the experiment. A new prime focus
corrector for theKPNO Mayall telescope delivers light to 5000 fiber optic
positioners. The fibers in turn feed ten broad-bandspectrographs. We describe
key aspects and lessons learned from the development, delivery and installation
ofthe fiber system at the Mayall telescope.
