A 16-channel arrayed waveguide grating （AWG） with an 800 GHz channel spacing in the O-band has been developed and fabricated based on silica planar lightwave circuit （PLC） technology. By extending the wavelength allocation from 8 channels to 16 channels as specified in IEEE 802.3bs， we increased the number of channels and boosted transmission capacity to meet the 1.6 Tbps and higher-speed signal transmission requirements for future data centers. Through optimizing the AWG structure， it has achieved insertion loss （IL） better than -1.61 dB， loss uniformity below 0.35 dB， polarization-dependent loss （PDL） below 0.35 dB， adjacent channel crosstalk under -20.05 dB， ripple less than 0.75 dB， center wavelength offset under 0.22 nm and 1 dB bandwidth exceeding 2.88 nm. The AWG has been successfully measured to transmit 53 Gbaud 4-level pulse amplitude modulation （PAM4） signal per channel and the total transmission speed can reach 1.6Tbps and above.