Amplified spontaneous emission (ASE) in organic dye DCM doped PMMA and DCM doped PMMA/silica gel hybrid material planar waveguide are investigated. By controlling of the refractive index and the thickness of the waveguide, the ASE wavelength can be seleted in a wide range and wavelength tuning is realized. The tuning range can reach 30 nm. The method can be applied to the wide band tuning of solid-state tunable lasers and optical amplifiers.