In this letter, we take advantage of the high coefficient of thermal expansion (CTE) of a chemically amplified, epoxy-based negative polymer (SU-8) to define a low-power consumption polymeric variable optical attenuator that combines the working principles of microoptoelectromechanical systems and photonic lightwave circuits. The SU-8 symmetric structure comprises a seismic mass and four mechanical beams. Three multimode waveguides are defined on this structure: two of them are located on the frame and the third one in the middle of the seismic mass. Aluminum is used as a heater electrode extending over two of the mechanical beams and part of the seismic mass. When a dc voltage is applied, the mechanical beams bend, resulting in a misalignment between the waveguides. Experimental results have shown a power consumption of 12 mW at 20 dB with a working wavelength of 633nm emitted from a light-emitting diode