Determination of the sensitivity of an autodyne acoustooptic fiber-waveguide transducer

A study was made of the parameters governing the maximum sensitivity of an autodyne acoustooptic fiber-waveguide transducer. When the fiber length was 10 m, the wavelength was 0.63 μm and the threshold sensitivity of the transducer was 1.5 X 10^–5 Pa · Hz^–1/2 at the quantum limit. This autodyne sensor was used in calibration of a source of acoustic-frequency pressures. The threshold sensitivity was determined experimentally for a laser autodyne transducer utilizing a single-mode quartz waveguide with a lacquer coating: when the waveguide length was 2 m the sensitivity amounted to 5 X 10^–4 Pa · Hz^–1/2 if an LG-77 laser was used.