Abstract: Tunable spectral filter includes a Fabry-Pérot interferometer (FPI), at least three actuators, at least three respective spring elements, and at least three respective sensors. The FPI includes two optical elements each having a partially reflective surface, with an optical cavity defining an optical gap between the two surfaces. The actuators, spring elements and sensors are disposed along the periphery of the optical elements. Multi-wavelength incident light enters the first optical element toward the optical cavity. Each actuator applies a selective force to move the optical element surfaces relative to each other, as the respective spring element applies an opposing force, thereby establishing an optical gap width, while maintaining the optical element surfaces substantially in parallel.