Maitland, Duncan J., IV

NASA NTRS1989

Fiber optic sensing systems using high frequency resonant sensing heads with intensity sensors

Optical fibers have an inherent capability of transmitting high bandwidth analog and digital signals. To apply this property of fiber optics to remote sensing, special sensing heads as well as signal processing electronics have to be developed. In systems employing intensity modulating sensors, there is also a need for a referencing technique to compensate for changes in the transmission of the connecting fibers and light source intensity. Fiber optic sensing systems incorporated in sensing heads of a special configuration are discussed. Different modes of operation as well as resonant conditions are explained. Theoretical and experimental analyses are also given.

Adamovsky, Grigory↗

NASA NTRS1988

Fiber optic sensing systems using high frequency resonant sensing heads with intensity sensors

Optical fibers have an inherent capability of transmitting high bandwidth analog and digital signals. To apply this property of fiber optics to remote sensing, special sensing heads as well as signal processing electronics have to be developed. In systems employing intensity modulating sensors, there is also a need for a referencing technique to compensate for changes in the transmission of the connecting fibers and light source intensity. Fiber optic sensing systems incorporated in sensing heads of a special configuration are discussed. Different modes of operation as well as resonant conditions are explained. Theoretical and experimental analyses are also given.

Adamovsky, Grigory↗

NASA NTRS1988

Fiber optic sensors with internal referencing

The main problem with amplitude modulating type sensors is that any variation in the intensity of the optical signal which occurs throughout the sensing system is interpreted by the photodetector as resulting from the sensor itself and is reflected as an error in the sensed parameter. To account for these errors, a referencing technique with the signal and reference channels separated in the time domain over the same fiber link can be used. Selected sensing and signal processing techniques involving temporally separated signal and referencing channels are described. A transition from the time into the frequency domain is also discussed. Experimental data are presented.

Adamovsky, Grigory↗