Planar waveguide spatial heterodyne spectrometer

Design and simulations of a Fourier-transform planar waveguide spectrometer are presented in the context of space-born observations of water in the near infrared spectral region. Spatial heterodyning of an optical signal is realized by using arrayed waveguide structures which produce spectrally dependent interference fringes. The light spectrum is calculated using discrete spatial Fourier transformation of the fringes. The arrayed waveguides form a multi-aperture input which markedly increases the optical throughput (étendue) of the device compared to single-aperture spectrometers.