A silicon based optical waveguide with 1.5% refractive index difference is used for data center interconnect on wavelength-division multiplexing chip. A 4-channel chip with same side， small size and low loss is designed and fabricated for data center transmitter. The size of the chip is 6.6 mm×2.2 mm， the minimum insertion loss is less than 2.33 dB， the 1 dB bandwidth is more than 11.35 nm， the polarization dependent loss is less than 0.14 dB， and the wavelength accuracy deviation is less than 0.38 nm. The optical performance can meet the wavelength-division multiplexing commercial specifications of the data center optical interconnect.