Simulation of optically encoded multiplexing for parallel multipoint sensing.

Spectral emission/absorption-based sensors are commonly used to monitor explosives, narcotics, and other restricted materials in high-security zones such as airports. Monitoring a broad range of spectral wavelengths with high spectral resolution would increase the repertoire of chemicals that can be monitored. However, a portable unit will have limitations in meeting these requirements. Optical fibers can be employed for collecting and transmitting spectral signals from portable sensor heads (PSHs) to a sensitive central spectral analyzer. However, simultaneous detection by sensors in multiple PSHs needs to be differentiated for identifying individual PSHs. An optical encoding method is presented in this paper for use of a portable unit for highly sensitive measurement. The methodology is demonstrated through a simulation using MATLAB Simulink.