A tunable Fabry-Perot filter (8, 118, 218, 318, 418) includes substrates (10, 12) with parallel generally planar facing principal surfaces (14, 16) including spaced apart facing reflective surface regions (20, 22) that are at least partially reflective over a wavelength range and define an optical gap (Gopt) therebetween. At least one substrate of the pair of substrates is light transmissive over the selected wavelength range to enable optical coupling with the optical gap. Electrodes (24, 26) are disposed on the facing principal surfaces of the substrates. The electrodes on the facing principal surfaces of the substrates are define an electrode gap therebetween such that electrical biasing of the electrodes simultaneously modifies the optical and electrode gaps.