The subject of this dissertation is to fabricate a tunable filter for WDM applications using thin film filters (TFFs). The center-wavelength shift of the TFF was obtained by heating up the TFFs. To enhance the thermal effect on the wavelength shift of the filters, the thickness of the TFFs were reduced from 1 mm to a minims thickness of 150£gm. Si benches with etched V-grooves were fabricated for precision positioning of the TFFs after thinning. For a 200 £gm ¡Ñ 200 £gm devices, maximum wavelength shift of 1.248nm was obtained by heating up the filter to 250¢XC. In addition, the wavelength shift due to thinning the substrate of the filters is also discussed.