A
spectrometer that provides the ability to combine the advantages of
high resolution, compactness, ruggedness, and low-
power consumption of Fabry-Perot (FP) tunable filter
spectrometer, with the multi-channel
multiplexing advantage of FT and / or
grating /
detector array. The key concept is to design and operate a tunable FP filter in a multiple-order condition. This filter is then followed by a “low-resolution” fixed
grating, which disperses the filtered n-order
signal into a preferably matched N-element
detector array for
parallel detection. The
spectral resolution in this
system is determined by the FP filter, which can be designed to have
very high resolution. The N-order
parallel detection scheme reduces the total integration or
scan time by a factor of N to achieve the same
signal to
noise ratio (SNR) at the same resolution as the single channel tunable filter method. This design is also very flexible, allowing
spectrometer systems with appropriate order N to thereby optimize the
system performance for
spectral resolution and scan integration time. In addition to the significant reduction in scan integration time, there are two other advantages to this approach. The first, because the FP tunable filter is designed and operated under n-orders, the fabrication tolerances of the FP filter cavity and operating conditions are significantly loosened.