Natural Fiber Span Reflectometer Proving a Virtual Differential Signal Sensing Array Capability
Patent application, Filed 7 Feb 2005
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
The objects of the present invention include the provision of 1 A time-domain reflectometer wherein an optical fiber span is the object of the reflectometry, and which provides output signals representative of acoustic pressure waves incident to the span solely by virtue of the natural, or innate, properties of commercial grade optical fiber cables. 2 The reflectometer described in object number 1, above, capable of providing acoustic wave signal sensing lengths of 5.0 km or more. 3 The reflectometer described in object number 2, above, which facilitates the provision of a very large plurality e.g. 5,000 or more virtual acoustic sensors along the span. 4 The reflectometer described in object number 1, above having a mode of operation which inherently attenuates undesired noises due to span line discontinuities, such as reflections caused by fiber cable couplings. 5 The reflectometer described in objects numbered 1 through 4, above, having special utility as a perimeter intrusion monitoring line for an acoustic security alarm system. 6 The reflectometer described in object numbered 1, above, which is capable of providing output signals in the form of a phase signal which varies linearly with the acoustic pressure wave. 7 The reflectometer described in object numbered 3, above, which is capable of providing output signals in the form of phase differential signals across pairs of the virtual sensors. 8 The reflectometer described in the object number 7, above, providing a capability of programmably selecting a pair, or pairs, of virtual acoustic sensors across which the phase signals are picked off, from among the plurality of virtual signals along the span.
- Acoustic Detection and Detectors
- Fiber Optics and Integrated Optics