Fabry-perot interferometer having an increased spectral band

A Fabry-Perot interferometer comprising:

• a fixed mirror structure having a fixed mirror in a spectral region;
• and
• a movable mirror structure including a movable membrane oppositely spaced from the fixed mirror structure, the membrane having a movable mirror in the spectral region, wherein
• the membrane has a plurality of springs in a peripheral region outside the spectral region, the plurality of springs being arranged one inside the other around the spectral region,
• one of the fixed mirror structure and the membrane has a plurality of first electrodes in the peripheral region,
• the other of the fixed mirror structure and the membrane has at least one second electrode in the peripheral region,
• the plurality of first electrodes and the at least one second electrode are located opposite to each other to form a plurality of opposing electrode pairs arranged one inside the other around the spectral region,
• a number of the plurality of springs is equal to a number of the plurality of opposing electrode pairs,
• the plurality of springs has a first spring and a second spring located closer to a center of the membrane than the first spring in a direction from an outer edge of the membrane to the center of the membrane,
• a spring constant of the second spring is less than a spring constant of the first spring,
• the plurality of opposing electrode pairs has a first electrode pair and a second electrode pair,
• a first voltage is applied to the first electrode pair during a first period to generate a first electrostatic force,
• a second voltage is applied to the second electrode pair during a second period to generate a second electrostatic force, and
• the first period overlaps the second period so that the membrane is displaced during the overlapping period by both the first electrostatic force and the second electrostatic force.