Research Progress on On‐Chip Fourier Transform Spectrometer

Abstract

A Fourier transform spectrometer (FTS) is recognized as a highly precise analytical instrument for analyzing the constituent elements of matter in the fields of physics, chemistry, aerospace, and so on. With the emergence and development of miniaturized and portable devices in numerous scientific and technological fields, there has been an urgent need for on-chip FTSs due to their benefits of small size, portability, low energy consumption, and robustness. However, the small size of on-chip FTSs hinders the acquisition of a large optical path difference, resulting in a low resolution of the spectrometer. In addition, the sampler spacing is not sufficiently small to satisfy Nyquist's sampling theorem, directly influencing the bandwidth of the spectrometer. Therefore, studies have been performed to investigate the trade-off between the reduced size and performance of spectrometers. This paper aims to systematically review the progress in on-chip FTSs, especially in on-chip static FTSs, including spatially modulated, temporally modulated, and space-time comodulated FTSs, from the aspects of theories, implementations, and performance indicators. Finally, the paper ends with a discussion of the challenges and a view of the prospective development of this exciting field.

Tunable Fabry-Pérot interferometer integrated in a silicon waveguide of an on-chip optical platform for long infrared wavelengths

“…The development of very small size and low-cost spectrometers for the infrared wavelength range that are suitable for a great variety of use cases is in the focus of many publications [1][2][3][4]. Modular approaches with the integration of components like waveguides, bends and couplers on one single chip are reported [5,6].…”

“…supplied by Hamamatsu), Hadamard transform spectrometers, MEMS-based Fourier transform spectrometers, Fabry-Pérot interferometer (FPI) based spectrometers, and spectrometers with linear optical filters and multi spectral sensors. In the development towards single chip spectrometers mainly MEMS-based Fourier transform spectrometers are on focus [2,10,11,12] followed by in-plane FPIs [13]. Such FPI filters are of particular interest because of their high integration potential.…”

Planar photonic chips with tailored dispersion relations for high-efficient spectrographic devices

“…To improve the spectral resolution, the narrow slits are always used in these instruments, which will block some portions of the light beam and then the optical signals cannot be efficiently used. The free spectral region of these high-resolution spectrometers is also much narrow, which increases the difficulties for measured the unambiguous wavelengths 12,13,14,15,16,17,18,19 . The triangular prism working as a light-splitting element has attract continuously attention since the first demonstration of refraction and dispersion in this prism, which was performed by British physicist Sir Isaac Newton in the late 1600s 20 .…”

Broadband and High-Resolution Integrated Spectrometer Based on a Tunable FSR-Free Optical Filter Array

“…Another challenge lies in inevitable fabrication imperfections for the large-scale filter array, which is crucial for small channel spacing. Fourier transform spectrometers (FTSs) can provide a higher signal-to-noise ratio compared to the conventional integrated spectrometers due to the higher received optical power or the Fellgett’s advantage. − The working principle of the FTS technique is to generate a time-domain interferogram of the input signal by modulating the optical path length within an interferometer, followed by the reconstruction of the optical spectrum via a Fourier transform. However, there are several drawbacks of the FTSs, including high power consumption, large driving voltage, long measurement time, and relatively large footprint.…”