The use of fiber-optic sensors in conjunction with florescence spectroscopy has found many uses in biochemistry, immunoassays, closed-aquaculture systems and other applications. However, the use of in situ fluorescence measurement during filed tests has been hampered by the physical limitations of spectrometers related to their size, weight and stability. To fulfill the need of a compact and portable spectrometer compatible with fiber- optic sensors in detection/analysis of fluorescence spectrum, American Research Corporation of Virginia proposes a novel fiber- optic Fourier-transform spectrometer (FOFTS) having no moving parts. Optical-path difference is achieved by the use of electrically addressed phase modulators in one of the Mach- Zehnder interferometric beam paths. This design provides rapid scanning, light weight and cost-effectiveness without compromising the performance of the spectrometer. The technical objectives of the Phase I program include selection of optical components for a fiber-optic interferometer, evaluation of methods to achieve optical-phase modulation, calibration of optical-phase modulators using laser and broadband light sources and acquisition of families of fluorescence data.
