0~1.7 [��m] band. For example, a spectrometer at the visible band may cost more than $2,000, while one at 1.55 [��m] may cost ten times higher [6].In spatial fringe formation, the scanning of the OPD of the processing interferometer is achieved by the use of a charge-coupled-device (CCD) array in order to detect the spatial interference fringes formed in the so-called ��electronically-scanned�� arrangement [7]. Reference [7, 3] used a Michelson interferometer with one of its two mirrors being slightly tilted to form the spatially distributed interference fringes. Computer simulations of reference [3] showed that the misidentification rate of central fringe was almost ��zero�� and the resolution of 1/400 fringe was obtained at 26 [dB] SNR.

Experiments in reference [7] have demonstrated a repeatability of 0.

02K within a 1K temperature range and the repeatability of 0.6K within a 100K temperature range for absolute temperature measurement. One of the main difficulties with the use of these configurations is the so-called spatial ��mis-overlapping ‘ of the beams, i.e. the cross-section of one beam cannot be exactly overlapped on that of the other [7]. As a result, the effective scanning range of the system will be reduced over what may otherwise be achieved.In temporal fringe formation, the adjustment of the OPD of the processing interferometer may be achieved by the use of sophisticated methods such as a piezoelectric transducer (PZT) to produce a ��mechanically-scanned�� interferometer [8] and OPD of the processing interferometer is scanned to match to that of the sensing interferometer.

Since the measurement is achieved by the comparison of the values of the OPDs of the two interferometers, this technique is immune to wavelength and power fluctuation induced noise. This technique also yields a high resolution Carfilzomib and a large dynamic range [9]. Reference Drug_discovery [10] showed that the fringe visibility out of white light sensor system, comprised of a sensing FFPI operating in the reflective mode and a reference FFPI operating in the transmissive mode, depends on the sensor (absolute) temperature. One drawback, however, is that fringe visibility is varying along the envelope of interferogram and fringe visibility gets reduced towards the outer region of interferogram.

This can limit the temperature range of operation, and thus be a drawback in some applications. Reference [11] proposed a white light interferometer using a bulk Michelson interferometer and two FFPIs (sensing FFPI and reference FFPI) and reported that 0.0025 fringe (0.013 K) of accuracy and dynamic range of room temperature to 1073K were obtained.