Analog Optical Transmission of Fast Photomultiplier Pulses Over   Distances of 2 km
  New LED-transmitters have been used to develop a new method of fast analog transmission of PMT pulses over large distances. The transmitters, consisting basically of InGaAsP LEDs with the maximum emission of light at 1300 nm, allow the transmission of fast photomultiplier pulses over distances of more than 2 km. The shape of the photomultiplier pulses is maintained, with an attenuation less than 1 dB/km. Typical applications of analog optical signal transmission are surface air shower detectors and underwater/ice neutrino experiments, which measure fast Cherenkov or scintillator pulses at large detector distances to the central DAQ system. 
A. Karle, T. Mikolajski, S. Cichos, S. Hundertmark, D. Pandel, C.   Spiering, O. Streicher, T. Thon, C. Wiebusch, R. Wischne...