Ultra‐Low‐Crosstalk Silicon Arrayed‐Waveguide Grating (De)multiplexer with 1.6‐nm Channel Spacing

Abstract A silicon arrayed‐waveguide grating (AWG) with 1.6‐nm channel spacing is proposed and realized with high performances for dense wavelength‐division (de)multiplexing systems. For the present AWG, the arrayed waveguides are broadened uniformly to be far beyond the singlemode regime, so that random phase errors and propagation loss are minimized even without any additional requirement for the fabrication process. Particularly, Euler‐bends are introduced for the arrayed waveguides to shrink the device footprint and suppress any excitation of higher‐order modes. As an example, a 16 × 16 AWG (de)multiplexer is realized with a compact footprint of 600 × 800 µm 2 by using single‐etched 220‐nm‐thick silicon photonic waveguides. When using the fabricated AWG to demultiplex the channels launched from the central input port, the excess loss and the adjacent‐channel crosstalk of the central output port are ≈2.2 and ≈−31.7 dB, respectively. Such an AWG is one of the best among silicon implementations.