A thermally tuneable, wide FSR switch, based on integrated-optic micro-ring resonators is described. This wavelength-selective switch allows high ON/OFF ratios combined with small dimensions. Furthermore allows the structure for a wide Free Spectral Range, since multiple resonators are used. This switch can be used in WDM filter arrays for a transceiver in an access network. Measurements of the thermal behaviour of a single resonator confirm the switching capability of the switch
