Up to now, we have studied an analog transmission scheme using direct modulation of distributed feedback (DFB) laser diodes with frequency modulation of several carriers which are multiplexed (FDM). We tested two systems, a 3-channel multiplexing prototype built by IDREL, coupled to a wide-band ORTEL optical link and a THOMSON 4-channel prototype.
Using the available cable we are now constructing the transmission
eight PMT signals using direct modulation and a
simple method of mixing, without RF multiplexing.