The impact of particle defects in the free propagation region on the performance of an etched diffraction grating demultiplexer is analyzed in the present paper. Numerical simulations using a method of moment and a Green function method show that particle defects with some special sizes can result in a strong resonance with the incident wavelength and will produce a large scattering loss. © 2006.
Cao, X., Wang, D., & Li, K. (2006). Effect of particle defects on an Echelle grating demultiplexer. Optics Communications, 263(1), 12–16. https://doi.org/10.1016/j.optcom.2006.01.011