We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 10 channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refractive index.
Two structures have been designed for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array : One is a seamless joint between the AWGs output waveguide and the photodiode; the other one has a shallow trench between the AWGs top cladding layer and the photodiode p-doped layer. The simulation results show that the photodiodes have quantum efficiencies as high as 87% and 64%, respectively, at 1.55µm wavelength.