optic architecture capable of multiplexing several sensors onto one common

This paper describes the design and performance of a rotary position sensor system based on the principle of wavelength division multiplexing. The system is discussed in relation to the requirements on the source, sensor and detection circuits. Measured performance of the various components is presented for environmental conditions typical of various application areas within the aircraft. The wavelength sensing technique becomes the basis for an electrooptic architecture capable of multiplexing several sensors onto one common interface. 1.0 INTRODUCTION Fiber optic systems for both commercial and military aircraft have been under consideration for some time. One reason for this consideration is that certain metallic structures, which provide electrical shielding, are being replaced with composite materials to reduce weight. At the same time, the threat of high energy radio frequency interference to aircraft electrical systems is increasing. Until recent years, more attention has been given to data bus requirements than has been given to fiber optic sensor systems. However, it is generally accepted that the data buses only represent a partial solution to the overall problem. Those conditions that point to the need for the fiber optic data buses also point to the need for fiber optic sensor systems. The need to develop optical sensor technology brings about the opportunity to develop a completely different approach to sensor system architecture. Many distinctly different interfaces are in use today for electrical sensors and to date a common sensor interface has not evolved. This certainly is a factor to be considered when designing optical systems to be cost competitive with electrical systems. The concept of a common optical modulation principal and thus the possibility to utilize a common sensor interface is not new. (1,2)