Pressure sensor. The sensor includes a deformable diaphragm responsive to applied pressure and a rigid beam mounted to move as the diaphragm deforms. The rigid beam includes a mirrored surface for receiving light from and reflecting light into an optical fiber thereby forming a Fabry-Perot cavity to detect changes in the position of the rigid beam. The rigid beam further includes inter-digital fingers extending from the mirrored surface and moving with the rigid beam with respect to fixed inter-digital fingers to create a change in electrical charges in the fingers to detect changes in the position of the rigid beam thereby providing two measures of rigid beam displacement which are measures of pressure. In a preferred embodiment, the optical fiber is a single mode optical fiber.