Theoretical and Experimental Study of the Optical Fiber Microphone.

Modifications to the previous condenser microphone theory yield new expressions for the membrane deflections at the center, which provide the basic theory for the optical fiber microphone. The theoretical analysis for the membrane amplitude and the phase response of the optical fiber microphone is given in detail in terms of its basic geometrical quantities. A relevant extension to the original concepts of the optical microphone includes the addition of a backplate with holes similar in design to present condenser microphone technology. This approach generates improved damping characteristics and was not previously considered. The work presented is based on trial and error computer modeling techniques. The construction and testing of the improved optical fiber microphone provides experimental data which is in good agreement with the theoretical analysis.