Arrayed Waveguide Grating (AWG) functioning as a demultiplexer is designed on SOI platform with rib waveguide
structure to be utilized in coarse wavelength division multiplexing-passive optical network (CWDM-PON) systems. Two
design approaches; conventional and tapered configuration of AWG was developed with channel spacing of 20 nm that
covers the standard transmission spectrum of CWDM ranging from 1311 nm to 1611 nm. The performance of insertion
loss for tapered configuration offered the lowest insertion loss of 0.77 dB but the adjacent crosstalk gave non-significant
relation for both designs. With average channel spacing of 20.4 nm, the nominal central wavelength of this design is
close to the standard CWDM wavelength grid over 484 nm free spectrum range (FSR).
A linear tapered double S-shaped arrayed waveguide grating (AWG) was designed as an alternative to a U-shaped AWG, and a complete transmission spectrum for 18 channels of coarse wavelength-division multiplexing (CWDM) was demonstrated. The silicon-on-insulator based AWG with a rib waveguide structure with a broad channel spacing of 20 nm was designed to serve as a multiplexer/demultiplexer. A beam propagation method modeling simulation under transverse electric mode polarization over a free spectrum range of 700 nm was used for the design process. The geometrical dimensions of the AWG rib structure were optimized to achieve the lowest reported insertion loss of 1.07 dB and adjacent crosstalk of −38.83 dB. The influence of different etching depths on the top Si layer of the AWG for a constant core width of 0.6 μm as well as birefringence effects were also investigated. A transmission spectrum response at the output port close to the standard CWDM wavelength grid range of 1271 to 1611 nm with an average channel spacing of 2485 GHz was obtained.