A system and method for a structure monitoring and locating a disturbance event is disclosed. The system includes a compact transceiver chip sending optical signals in three optical fibers that encompass the monitored structure appropriately. The fiber arrangement has different density in different parts of the monitored structure, such as, for example, critical places in the structure may have larger number of fiber loops surrounding them. All fibers transmit signals in both directions: from the transceiver to a returning point and back. A set of two detectors registers the returning signals, and a time delay between those signals is calculated, which is indicative of the disturbance event location. Polarization states of the returning signals are controlled by transceiver built-in controllers. The event location is determined with different sensitivity in different parts of the monitored structure depending on the density of fibers in these parts.