The next figure shows the principle of operation for this device. This is an intensity-type sensor in which light is coupled into the waveguide film from either edge. Principle of operation of the cantilever beam. The light in the channel guides is confined in-plane by the refractive index profile of the fillms and guided around the surface by etched ridges in the film which have been patterned by photolithography. Beam deflection is determined optically by a decr ease in the light coupled between the two separated waveguides.
Maximum coupling occurs when the two channel guides are aligned.
Small displacements on the order of a few hundred angstroms should be detectable. This solution is h eated to boiling and the wafers are soaked in this for 10 minutes. The wafers are then rinsed in DI water again, and then blown dry with a nitro gen gun. The initial oxidation is done in a lab furnace at 1100 degrees C, in a wet ambient. The bubbler is cleaned with DI water and HF acid and then filled with DI water.