Distributed Etched Diffraction Grating Demultiplexer With Flat-Top Insertion Loss Envelope

It is numerically shown that incorporation of a distributed Bragg reflector at the facets of an etched diffraction grating (EDG) can be used to tailor the output spectral response of the device. This technique is used to optimize the overall insertion loss envelope of a distributed etched diffraction grating (DEDG) demultiplexer to improve the output channel uniformity. Numerical results are presented for the transverse electric (TE) polarization, where a channel uniformity of 0.45 dB over 43-nm bandwidth is achieved. A finite-difference time-domain (FDTD) method in combination with perfectly matched layers (PMLs) and periodic boundary condition (PBC) is used to calculate the insertion loss envelope of device.