Fiber-optic flexural disk accelerometer

Abstract

The fabrication and calibration of a fiber-optic flexural disk accelerometer is discussed in this thesis. The accelerometer is comprised of a cylindrical body with thin, flexible end plates (or disks) and an interior spindle coupling the disks together ensuring proper phasing. The sensing mechanism is comprised of single mode optical fiber wound into flat coils and epoxied on to the inside faces of the disks, forming the legs of a Michelson interferometer. The use of both legs of this fiber-optic interferometer as sensing elements provides a "push-pull" enhancement and effectively doubles the accelerometer's response while providing common-mode rejection of pressure and temperature variations. The acceleration sensitivity for a sensor consisting of two 1.8" by 1/25" disks is delta0/a(6) = 49 radians/g with a resonance frequency of 2450 Hz. the fractional phase change per unit force is delta0/0ma(c) = 5.5 x 10(-6) N(-1).