Signal-to-noise characteristics of photodiode array fourier transform spectrometers

The signal-to-noise characteristics of two configurations of photodiode array Fourier transform spectrometers are compared with that of a conventional grating spectrograph using an identical photodiode array. One configuration uses a Sagnac-type common path triangle interferometer, the other uses a stationary tilted mirror Michelson interferometer. While the common path triangle configuration has the property that the resolving power is independent of the field position, theS/N for both is reasonably comparable to the grating spectrograph.