This paper gives a brief review of the limiting spectral characteristics of planar demultiplexers, taking into account crosstalk. The characteristics of volume demultiplexers are investigated and exhibited, using as an example a demultiplexer based on a concave diffraction grating.
Yu. V. Bazhanov, S. N. Markov, K. N. Kostenko, and M. Ya. Yakovlev, "Demultiplexers based on diffraction gratings and their limiting characteristics," J. Opt. Technol. 73, 445-448 (2006)