Other

US Government As Represented by the Secretary of the Army

Christopher J LaVigna

James S Sirkis

Sheldon J Cytron

Shiping Chen

Yaowen Li

Justin M Bowlus

Harry G Kwatny

An apparatus for measuring exit velocity of a round from a muzzle of a gun barrel includes a first optical fiber having a first fiber optic Bragg grating (FBG) circumferentially attached to the gun barrel at the muzzle and a second FBG circumferentially attached to the gun barrel further from the muzzle than the first FBG; a coupler that receives one end of the first optical fiber; a light source connected by a second optical fiber to the coupler for supplying light to the first optical fiber; a third optical fiber comprising an FBG notch filter, the third optical fiber being connected to the coupler to receive light reflected from the first optical fiber; a notch filter mount attached to the gun barrel, the FBG notch filter being disposed in the notch filter mount; a photodetector connected to an end of the third optical fiber; and data processing electronics electrically connected to the photodetector.

Apparatus and method for measuring exit velocity of a gun round

A fiber optic sensor employs tapered fiber optics in a tapered gun barrel. The fiber optic sensor employs a single-mode optical fiber, a light source supplying light to the single-mode fiber and at least one tapered dual-mode optical fiber secured to the barrel in a longitudinal direction. The single-mode fiber is spliced to with an end of a proximal one of the dual-mode fibers for carrying the light signal. A partial reflector is inserted between the dual-mode fibers to partially reflect and partially transmit light. A reflector is coupled to a distal end the dual-mode fiber, at the open end of the muzzle of the gun, to reflect the transmitted light. A coupler couples the single-mode fiber to the proximal dual-mode fiber. A coherent multiplexer is connected to the coupler for receiving and multiplexing the reflected light. A processor is responsive to the multiplexer for processing the multiplexed sensing information. The dual-mode fiber is tapered inversely with respect to the tapered muzzle to simplify the processing function. When two or more dual-mode fibers are employed, an offset splice is provided between the dual-mode fibers. A method is also disclosed.

Fiber optic sensor for spatially separated elements in a system

Growing community of inventors

Olney, MD, United States of America

Christopher J LaVigna