A large-scale arrayed-waveguide grating with a 400-channel and 25GHz spacing using 1.55-Delta silica-based waveguides on a 6-inch Si wafer has been realised. Good demultiplexing properties have been obtained over the full C- and L-band range with an on-chip loss of 3.8 to 6.4dB and a far-end crosstalk of -30dB.