Abstract: An optical fiber sensing system is disclosed for sensing presence of an acoustic event such as acoustic waves or vibration along a path. The sensing system includes means for producing a plurality of pulses of coherent light. The system includes a first optical sensing fiber for receiving at least a first portion of the pulses of coherent light and adapted to be positioned along the path, the first optical sensing fiber producing first backscattered light in response to receiving said pulses of coherent light. The system includes a second optical sensing fiber for receiving at least a second portion of said pulses of coherent light pulses and adapted to be positioned along said path, the second optical sensing fiber producing second backscattered light in response to receiving said pulses of coherent light.