Organic nonlinear optical materials have stimulated much interest for their large nonresonant nonlinearities

high-speed response

ease of fabrication and low cost. There are a number of different ways to fabricate polymer channel waveguides

such as reactive ion etching and groove filling etc. This paper reports a simple technique of UV photobleaching which can be used to prepare ridge channel waveguide with DANS (4-dimethylamino-4'nitro-stlibene)-PMMA (polymethyl methacrylate) side-chain polymer film. UV photobleaching is an attractive method for fabricating polymer optical waveguides because the process is simple and exposure time can be adjusted easily

so as to control the refractive index changes of the polymer film. The corresponding main technique is discussed in the paper. The complicated photochemical reaction will happen when DANS-PMMA side-chain polymer film is exposed to the high pressure Hg lamp. We can notice that both the refractive index and the thickness of the DANS-PMMA film are reduced after photobleaching. This process is usually called UV photobleaching of the polymer film. For DANS-PMMA film

we have processed a series of UV photobleaching experiments. Under appropriate UV photobleaching condition

combined with metal covered technique

a new type of DANS-PMMA polymer ridge waveguide was prepared. First

the Al film was deposited on the surface of DANS-PMMA film and formed pattern of waveguide by photolithography and etching. Second

the sample was exposed to the high pressure Hg lamp for some time. Then

the new type of ridge waveguide is formed. Besides

the technique does not require photolithography or etching on polymer film

so very flat waveguide side walls can be formed. With the microscope we can observe the perfect shape of the DANS-PMMA ridge waveguide.The smooth walls of the ridge waveguide are helpful to reducing the scattering losses and improving the quality of the waveguide. The experiment proved that UV photobleaching process depended on time

distance and temperature of bleaching. The rate of UV photobleaching will increase when environment temperature is risen.