System and method for passive optical monitoring of the concentration of multiple gases and/or multiple parameters at multiple points

A system for passive optical monitoring of the concentration of multiple gases and/or multiple parameters at multiple points, comprising:

• an optical signal sending, detecting and analyzing unit, wherein the unit emits optical pulses with emission wavelength centered on the methane absorption line λ1, with a detector for the detection of the return optical signals and element for the calculation of the methane concentration for each passive sensor element;
• an optical switch or set of optical switches with a function of routing the optical signals to K optical arms for the distributing units and respective passive optical sensors;
• the optical signals sending, detecting and analyzing unit together with the optical switch or set of optical switches occupies the same packaging and physical space constituting an element called an optical interrogator;
• an optical splitter comprising one input optical fiber that is a single-mode type with N output optical fibers, to equally distribute the optical signals to the N sensors;
• delay lines comprising a fixed and defined length of optical fiber that can be of the single-mode type, related to the duration of the optical pulse, to temporarily delay the optical pulse initially sent from the unit in each arm of the optical splitter so that in the unit it temporarily splits the information coming from the several sensors in the detection process;
• the optical splitter elements and the delay lines occupy a same packaging and physical space, constituting a distribution box;
• sensor elements which expand the optical signals in a light beam and allow the interaction of light with the methane gas inside, enabling the quantification of the concentration of this gas, the element is reflective, the optical signals interacts with the gas and is reflected by a mirror constituting the sensor element and again interacts with the gas, duplicating the optical path of interaction, the optical signals then returns to the element;
• the optical splitter elements and the delay lines, together with the optical sensors, constitute the passive elements (of the system and are distributed and repeated in a modular way to increase the number of monitored points, totaling N×K monitoring points.