A micro-demultiplexer of a coupled resonator optical waveguide composed of polystyrene microspheres is fabricated by a self-assembly technique in colloidal suspension on a lithographically patterned substrate. The spectrum of propagating light taken at the 60 degrees-branch (Point 2) shows sharper peaks than that taken at Point 1 while the spectrum taken at the 30 degrees-branch (Point 3) shows broader peaks.