A method and system producing and transmitting pulsed or continuous wave signals through one or more optical fibers to a plurality of remote sensors provided in a hostile environment. The produced signals transmitted along one of the optical fibers would be demultiplexed and transmitted to separate sensors. The sensors would then modulate these signals which would then be combined onto a single output optical fiber which is to be analyzed. A spectrometer or other signal processing device, generally included in a shielded environment, would be utilized to process the modulated signals.