Novel layout for reflective arrayed waveguide gratings based on Sagnac   loop reflectors with custom spectral response
  A novel layout for a reflective Arrayed Waveguide Grating is presented in this paper. The device consists of one half of a regular AWG where each arm waveguide in the array is terminated with a phase shifter and a Sagnac loop reflector. The theoretical model to describe and design the spectral response of this device is derivated. By individually adjusting the phase shifter and Sagnac reflectivity in each arm, this layout allows for tailoring the spectral response of the AWG. Design cases of Silicon-on-Insulator AWG devices with Gaussian and flattened response are provided. 
Bernardo Gargallo and Pascual Mu\~noz
physics.optics