Wavelength division multiplexers/demultiplexers and variable optical attenuators(VOAS) are key devices used in optical communication systems. In order to get their monolithic integrated chip with simple fabrication process and fast time response, and considering the possibility of it to integrate with other different optical devices, a 16-channel 200 GHz arrayed waveguide grating(AWG) multiplexer/demultiplexer was monolithically integrated with electro-absorption variable optical attenuators on a silicon-on-insulator (SOI) platform. The on-chip loss was less than 7 dB and the crosstalk was less than -22 dB. The power consumption of the electro-absorption VOA is 572.4 mW(106 mA, 5.4 V) at 20 dB attenuation. Besides, the device provides fast optical power attenuation, and in a 0-5 V square voltage, the rising/falling time of the VOA is 50.5 ns and 48 ns, respectively.