152 results about "Fourier transform spectrometers" patented technology

A Fourier Transform (FT) spectrometer apparatus uses multi-element MEMS (Micro-Electro-Mechanical-Systems) or D-MEMS (Diffractive Micro-Electro-Mechanical-Systems) devices. A polychromatic light source is first diffracted or refracted by a dispersive component such as a grating or prism. The dispersed beam is intersected by a multi-element MEMS apparatus. The MEMS apparatus encodes each spectral component thereof with different time varying modulation through corresponding MEMS element. The light radiation is then spectrally recombined as a single beam. The beam is further split into to a reference beam and a probe beam. The probe light is directed to a sample and then the transmitted or reflected light is collected. Both the reference beam and probe beam are detected by a photo-detector. The detected time varying signal is analyzed by Fourier transformation to resolve the spectral components of the sample under measurement.

A transform spectrometer implemented on a planar waveguide circuit (PLC), having an input optical signal waveguide carrying an input optical signal to be analyzed; a plurality of couplers, each connected to the input optical signal waveguide, and each including a coupler output for carrying a coupled optical signal related to the input optical signal. An array of interleaved, asymmetrical waveguide Mach-Zehnder interferometers (MZI) is formed on the PLC, each having at least one input MZI waveguide, each MZI input waveguide receiving a coupled optical signal from a respective coupler output; wherein at least some of the input MZI waveguides intersect in a common layer of the PLC, at an angle which allows their respective coupled optical signals to transmit without unacceptable attenuation. This arrangement improves spatial efficiency of the PLC, allowing more MZIs to be implemented, resulting in increased spectral resolution.

The invention relates to a Fourier transform spectrometer on a silicon substrate and a method for obtaining a reconstructed spectrum of a light source. The spectrometer comprises a waveguide input coupler, a cascade optical switch, a non-equal-arm sub-wavelength grating (SWG) waveguide pair and a germanium-silicon detector, and the cascade optical switch is connected through the non-equal-arm SWGwaveguide pair. A series of non-equal-arm Mach-Zehnder interferometer (MZI) arrays with different optical path differences are formed by adjusting an optical switch state gating optical path, a Fourier transform spectrometer based on spatial heterodyne coherence is realized, and a spectrum is reconstructed by using a compressed sensing algorithm. Compared with a traditional passive MZI array structure, the chip size can be effectively reduced, and the number of sampling points is increased; wherein the unequal-arm SWG waveguide pair can effectively improve the temperature stability of the chipand expand the working bandwidth. According to the invention, the application requirements of the Fourier transform spectrometer on miniaturization and portability can be met, and the problem that the spectrometer on the existing silicon substrate is generally sensitive to temperature can be solved.

A Micro-Electro-Mechanical Systems (MEMS) interferometer is implemented in a Fourier transform spectrometer, which includes a common housing containing the interferometer and a gas cell, possibly including a preconcentrator. The interferometer system includes an optical bench and at least two mirror structures, being patterned from one or more layers on the optical bench and erected to extend substantially perpendicularly to the bench to define two interferometer arms to provide a MEMS interferometer.