Nowadays, an important device called vertical cavity surface emitting laser is applied into optical interconnection more and more widely, it works at 850 nm and its output cross section is 50 μm×50 μm. In order to fit to this device, a muti-mode rib waveguide with a big cross section is needed. And the distance among chips needs longer the waveguide. A waveguide which is 21 cm long with a big section is fabricated through advancing the making technology and light can go through it successfully. A measurement system is also designed and the average wasting of the waveguide as 0.18 dB/cm is gotten which is verified through cutting-off method. Also, this system can be applied to adjusting the coupling of the waveguide input with invisible light.