Abstract: In an apparatus and method for operating an apparatus having a mobile part which is movable on a movement plane and has a measuring unit, and a measuring body which is set apart from the movement plane and from the plane parallel to the movement plane that includes the measuring unit, for example, and is situated as far as possible from the movement plane, the measuring unit is adapted to determine the distance between the measuring body and the measuring unit in a normal direction to the movement plane, and the measuring body is shaped such that in the projection of the measuring body perpendicular onto the plane, e.g., the projection surface, an individual distance value is bijectively allocated to the, or to the plurality of, partial surface regions of the projection surface, which particularly do not overlap one another.

Abstract: A scanner controller has an acceleration/deceleration computation unit configured to perform an acceleration/deceleration control for an instructed speed and controls a laser output power depending on the instructed speed and a result of the acceleration/deceleration control. This scanner controller further has a robot deceleration rate computation/determination unit configured to externally output information on a speed after being subjected to the acceleration/deceleration control.

Abstract: In various embodiments a spectrometer is provided. The spectrometer may include a first mirror unit which is semitransparent for electromagnetic radiation of at least one wavelength or wavelength range; and a second mirror unit having a first area and a second area facing the first mirror unit, wherein at least a part of the first area and the second area are spaced apart from the first mirror unit, wherein the first area is at least partially reflective for the electromagnetic radiation of at least one wavelength or wavelength range, wherein the second area includes at least a part of a photodetector, and wherein the photodetector is configured to detect the electromagnetic radiation of at least one wavelength or wavelength range.

Abstract: A light measurement device comprising an optical sensor that includes a tunable interference filter and a detecting section detecting light passed through the tunable filter, a storing section that stores a first correlation data and a second correlation data, and a CPU that obtains amount of the light by controlling the optical sensor based on the first correlation data and a second correlation data.

Abstract: An optical filter includes fixed substrate, a movable substrate opposed to the fixed substrate, a first reflection film provided on a surface of the fixed substrate facing the movable substrate, a second reflection film provided on the movable substrate and opposed to the first reflection film across a gap, a first electrode formed to cover the first reflection film and to extend beyond an outer circumference of the first reflection film, and a second electrode provided on a surface of the movable substrate facing the fixed substrate and opposed to a part of the first electrode, and the first electrode is formed of a light-transmissive material, and the first electrode and the second reflection film are electrically connected at the same potential.

Abstract: An apparatus and method for estimating a parameter of interest using values of a beam property from two or more electromagnetic beams that both pass through at least part of an optical displacement device. The apparatus may include a Fabry-Perot interferometer, a collimated light source, and a detection array. At least one mirror of the interferometer may be operably coupled to an element receiving an external stimulus, such as pressure, force, and/or acceleration. The method includes using the apparatus.

Abstract: The instant disclosure describes an optical device for the interferometric analysis of the surface condition of an object, including: a light source; an optical fiber capable of receiving the incident light wave and transmitting said wave to the object; a detector capable of detecting a combination between a light wave reflected by the optical fiber and a light wave returned by the object; and in which the optical fiber has a free end in the shape of a cone, with a vertex angle of between 15 and 25 degrees, the tip of the cone having dimensions of less than 50×50 nm, and the tip of the cone being placed, while in use, at a distance of between 5 and 50 ?m from the surface of the object.

Abstract: Device and method for acquiring position with a confocal Fabry-Perot interferometer. In a general aspect, the device for acquiring position may include an arrangement for acquiring position where the acquiring arrangement has a confocal Fabry-Perot interferometer. In another general aspect, a method for acquiring position may include generating an interference pattern dependent on a position of an object by a confocal Fabry-Perot interferometer; detecting the interference pattern to obtain a measuring signal; and evaluating the measuring signal.

Abstract: A non-energy dissipating, curvature sensing device senses curvature variation of a sample and comprises an outer layer, an inner layer and at least one spacer. The outer layer is flexible, transparent material and has a shape. The inner layer is flexible, transparent material, has a shape corresponding to the shape of the outer layer, is positioned under the outer layer and is thicker and harder than the outer layer. At least one spacer is positioned between the outer layer and the inner layer and creates space between the outer layer and the inner layer. A non-energy dissipating, curvature sensing method is also disclosed.

Abstract: An optical filter according to the invention includes: first and second substrates opposed to each other; first and second reflecting films provided to the first and second substrates; first and second bonding films provided to the first and second substrates; and first and second barrier films disposed on surfaces of the first and second reflecting films, wherein the first barrier film has a transmittance of ozone lower than a transmittance of ozone the first reflecting film has, and the second barrier film has a transmittance of ozone lower than a transmittance of ozone the second reflecting film has. Accordingly, the reflecting films are protected from ozone or ultraviolet radiation during the manufacturing process of the optical filter and thereby the optical filter characteristics is prevented from being deteriorated.

Abstract: A method of manufacturing an optical filter according to the invention includes the steps of forming a first bonding film in a first bonding area of a first substrate provided with a first reflecting film, forming a second bonding film in a second bonding area of a second substrate provided with a second reflecting film, irradiating the first bonding area with ozone or an ultraviolet ray using a first mask member, irradiating the second bonding area with ozone or an ultraviolet ray using a second mask member, and bonding the first bonding film and the second bonding film to each other to bond the first substrate and the second substrate to each other, thereby protecting the reflecting films from ozone or ultraviolet radiation to prevent the reflecting films from being deteriorated in the manufacturing process.

Abstract: Apparatus, methods, and other embodiments associated with measuring multiple Fabry-Perot gaps to determine environmental parameters are described herein. In one embodiment, a system for measuring environmental parameters includes an optical fiber, a first reflective surface, a second reflective surface, a third reflective surface, and a light source. The first reflective surface is positioned proximate to a first end of the optical fiber. The second reflective surface is positioned to form a first Fabry-Perot gap between the first reflective surface and the second reflective surface. The third reflective surface is positioned to form a second Fabry-Perot gap between the second reflective surface and third reflective surface. The light source provides light to the optical fiber, wherein the optical fiber delivers light from the light source to the first Fabry-Perot gap and the second Fabry-Perot gap and the optical fiber receives reflected light from the first Fabry-Perot gap and the second Fabry-Perot gap.

Abstract: A method for forming a structure comprising multiple parallel surfaces having a precise separation is disclosed. Precise separation and parallelism of the surfaces is achieved through the use of an adhesive mixture that comprises a plurality of spacers having a dimension substantially equal to the desired separation.

Abstract: Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.

Abstract: An apparatus and method for analyzing biological cells and other particles using an external laser cavity. Microfluidic channels contain and transport biological cells to be analyzed. A laser diode provides light for cell analysis. An external cavity is provided between one surface of the laser diode and a mirror opposite thereto. A microlens set focuses the light on only one cell as it passes through the external cavity. The presence of the cell in the external cavity gives a weak feedback toward the laser diode. The emission frequency and the output power of the laser are both functions of the length of the external cavity. Therefore, the variation of cavity length can be deduced from these parameters, where the variation is caused by changing the refractive index or size of the cell in the cavity.

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: An optical displacement sensor is disclosed comprising a beam splitter having two optically coupled and mechanically coupled optically resonant cavities. The respective cavity lengths of the optically resonant cavities are functions of an environmental stimulus. By virtue of the optically coupled optically resonant cavities, the output of the beam splitter is less sensitive to input wavelength variation yet retains high sensitivity to the environmental stimulus.

Abstract: A pressure measurement system and method are described. The system uses a tunable laser and a Fabry-Perot sensor with integrated transducer. A detector senses the light modulated by the Fabry-Perot sensor. A signal conditioner, which can be located up to 15 km away, then uses the detector signal to determine the displacement of the diaphragm, which is indicative of pressure exerted against the diaphragm. Use of a temperature sensor to generate a signal, fed to the signal conditioner, to compensate for temperature is also contemplated.

Abstract: An interferometric sensing arrangement includes an interferometric sensor having an optical path length that varies depending on one or more physical parameters to be measured using the interferometric sensor. One or more light sources are used to generate light at three or more predetermined different fixed wavelengths. In a preferred example embodiment, four fixed wavelength lasers are used to generate light at four predetermined different fixed wavelengths. An optical coupler couples the multiple wavelength light to the interferometric sensor, and a detector measures an amplitude response of an interferometric signal produced by the interferometric sensor. A controller determines the optical path length based on the measured amplitude response.

Abstract: An apparatus and method for detecting multiple beams from a beamsplitter is disclosed. Some embodiments of the present invention are particularly well-suited for use in microphones, high-sensitivity pressure sensors, vibration sensors, and accelerometer applications. Some embodiments of the present invention generate a differential electrical output signal that is based on multiple detected optical signals. The differential output signal is generated in response to an environmental stimulus, such as a pressure differential or incident acoustic energy. In accordance with the illustrative embodiment, an optical displacement sensor redirects the transmitted beam back through the optically-resonant cavity with an angular offset. Due to the angular offset, the redirected beam (i.e., retransmitted beam) transits the cavity with an intra-cavity path length that corresponds to substantially full transmittance of the retransmitted beam in the absence of the environmental stimulus.

Abstract: A device to measure a fluid pressure comprises a pressure sensing element 10 and a pressure readout element 20. The pressure sensing element 10 comprises a cavity 11 capped by a flexible membrane 13, the cavity having a length d that varies with the fluid pressure P1 applied on the flexible membrane 13. The pressure readout element 20 comprises a light source 24 for providing an incident beam of a determined wavelength range directed towards the cavity and an optical spectral analyzer 25 for measuring a power spectrum of a return beam reflected by the cavity, and processing means 27 for determining the cavity length d and the fluid pressure P1 based on the power spectrum.

Abstract: A feedback-control circuit for color calibration of a diffraction light device includes at least one diffractive light device (DLD) having a gap distance defined by opposing plates, at least one sensor configured to convert light modulated by the DLD device into a light signal indicative of the gap, a controller configured to calculate a voltage correction value based on a difference between the gap as indicated by the light signal and a designer-specified gap value and being further configured to apply a corrected voltage corresponding to the voltage correction value to the DLD device.

Abstract: Micron-scale displacement measurement devices having enhanced performance characteristics are disclosed. One embodiment of a micron-scale displacement measurement device includes a phase-sensitive reflective diffraction grating for reflecting a first portion of an incident light and transmitting a second portion of the incident light such that the second portion of the incident light is diffracted. The device can further include a mechanical structure having a first region and a second region, the mechanical structure positioned a distance d above the diffraction grating and forming a wall of a cavity, the second portion of the incident light is reflected off of the first region of the structure such that an interference pattern is formed by the reflected first portion and the reflected second portion of the incident light. The device can further include an orifice formed in the cavity to provide for the passage of air between the inside and outside of the cavity.

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: A pressure measurement system and method are described. The system uses a tunable laser and a Fabry-Perot sensor with integrated transducer. A detector senses the light modulated by the Fabry-Perot sensor. A signal conditioner, which can be located up to 15 km away, then uses the detector signal to determine the displacement of the diaphragm, which is indicative of pressure exerted against the diaphragm. Use of a temperature sensor to generate a signal, fed to the signal conditioner, to compensate for temperature is also contemplated.

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: Disclosed herein are methods and apparatus for testing interferometric modulators. The interferometric modulators may be tested by applying a time-varying voltage stimulus and measuring the resulting reflectivity from the modulators.

Abstract: An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

Abstract: A broadband light source with a sufficiently long coherence length is impinged on the optical cavity. The broadband laser light reflects from the first and second surfaces of the cavity. The two light beams, either reflected or transmitted, are phase shifted from one another by an amount proportional to the optical path length of the cavity and inversely proportional to the wavelength of the light (4?nd/?) The two light beams interfere with each other and form a modulated light beam that has a spectrum approximately like the laser's broadband spectrum multiplied by a cosine with a frequency 4?nd/?. The modulated light beam is coupled to a spectrometer that measures the intensity of the light as a function of wavelength over a range of wavelengths. The Fourier transform of the spectrum contains a peak that is related to the OPL and is located at 2*n*d where n*d is the OPL.

Abstract: Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.

Abstract: Integrated spectroscopy systems are disclosed. In some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources. The tunable source combines one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon. The advantages associated with the use of the tunable etalon are that it can be small, relatively low power consumption device. For example, newer microelectrical mechanical system (MEMS) implementations of these devices make them the size of a chip. This increases their robustness and also their performance. In some examples, an isolator, amplifier, and/or reference system is further provided integrated.

Abstract: A method for calibrating a display device comprises controlling an applied voltage to at least one fabry-perot interferometer pixel through a plurality of switches. The at least one fabry-perot interferometer pixel has a top and a bottom plate defining a gap therebetween wherein the at least one fabry-perot interferometer pixel produces a selected output color in response to the applied voltage. The method further includes controlling a test voltage to the at least one fabry-perot interferometer pixel through the plurality of switches during a calibration sequence to determine a gap capacitance in the at least one fabry-perot interferometer. The gap capacitance represents the relative position of the top plate with respect to the bottom plate.

Abstract: A sensor and method for using the same is disclosed. The sensor includes an optical cavity defined by first and second mirrors that have a spacing therebetween that varies in response to a force applied to the sensor and to a control voltage. The sensor has a drive circuit that measures light leaving an output port that samples light in said cavity and applies the control voltage to the optical cavity such that the spacing between the mirrors remains at a predetermined value independent of the force, the control voltage determining an output signal that provides a measurement of the force applied to the optical cavity. In one embodiment, the first mirror is fixed to the second mirror by a spring mechanism that causes the first mirror to move away from the second mirror, and the control voltage causes the first mirror to move toward the second mirror.

Abstract: This invention relates to an optical displacement sensor element, e.g. for use in a pressure sensor or a microphone, comprising two essentially flat surfaces being separated by a cavity being defined by a spacer, the distance between the surfaces being variable thus providing a displacement sensitive Fabry-Perot interferometer. Both of said surfaces are at least partially reflective, and in that said first surface is provided with at least one optical detector, and one of surfaces being provided on an at least partially transparent material.

Abstract: The present invention provides a relatively simple etalon testing system and process for measuring cavity error of etalons to high precision. It works equally well on solid and air-spaced designs. This invention should be a great aid in the manufacture of high performance etalons, separating out the geometric and reflectivity finesses. The present invention permits measurement of etalon spacings to an accuracy of better than ?/1000 (i.e., about 63 picometers [6.3×10?11 m] when using a HeNe test laser). In a preferred process an etalon under examination is mounted on a rotational stage illuminated with a collimated beam from a HeNe laser. Reflections from the etalon are imaged on a screen to produce interference fringes which are monitored by a CCD camera. The etalon is then pivoted about an axis perpendicular to the laser beam and images of the interference patterns are recorded periodically to produce a plot of intensity vs. pivot angle over a pivot range sufficient to include at least one extinction cycle.

Abstract: A method for calibrating an interferometer uses an actuator adapted to control an optical gap in response to application of an electrical signal. The interferometer is illuminated with a beam of light having a predetermined substantially monochromatic wavelength, oriented at a first predetermined angle of incidence, and light reflected from the interferometer at a second predetermined angle is detected while varying an electrical signal applied to the actuator, thereby establishing a calibrated relationship between the applied electrical signal and an optical path length of the interferometer.

Abstract: A method of tuning a resonant cavity of an FP (Fabry-Perot) interferometer in a DLD (diffractive light device) MEMS (microelectromechanical system) device, wherein the FP interferometer has a top plate and a bottom plate, and wherein the method comprises; using first and second electromechanical transducers to independently change a distance between the top and bottom plates of the FP interferometer.

Abstract: The method for making the fiber optic Fabry-Perot sensor includes securing an optical fiber to a substrate, and forming at least one gap in the optical fiber after the optical fiber is secured to the substrate to define at least one pair of self-aligned opposing spaced apart optical fiber end faces for the Fabry-Perot sensor. Preferably, an adhesive directly secures the at least one pair of optical fiber portions to the substrate. The opposing spaced apart optical fiber end faces are self-aligned because the pair of optical fiber end portions are formed from a single fiber which has been directly secured to the substrate. Also, each of the self-aligned spaced apart optical fiber end faces may be substantially rounded due to an electrical discharge used to form the gap. This results in integral lenses being formed as the end faces of the fiber portions.

Abstract: Apparatus and methods are provided for measuring a selected optical behavior of a tunable opto-electric device by using the electrical characteristics of the opto-electronic device. The benefit of the present invention is the elimination or reduction in complexity of optical wavelength reference hardware that is currently required for wavelength referencing and locking. Accordingly, the present invention reduces the cost and complexity of the optical packaging of tunable opto-electronic telecommunication components. Furthermore, the present invention also significantly simplifies optical and electronic design of system level products with tunable opto-electronic devices.

Abstract: A tunable optical filter including at least one deformable membrane actuator. The actuator may include an array of a thousand or millions of individual actuator cells for strength and mechanical robustness. The deformable membrane actuator including a first primary substrate having a first optical portion, an electrically conductive and deformable membrane, an electrically conductive primary substrate electrode and a membrane support structure. The substrate electrode and the membrane support structure are disposed on or adjacent to the first primary substrate, the deformable membrane being supported by the membrane support structure, and a second substrate having a second optical portion. The second substrate is supported by a load support structure disposed on one surface of the deformable membrane and is located a distance from the first substrate.

Abstract: An etalon has at least one transparent plate, wherein the transparent plate consists of lithium tantalate single crystal, an etalon has at least one transparent plate, wherein the transparent plate consists of lithium niobate single crystal and a method for producing an etalon, which includes at least growing a single crystal of lithium tantalate or lithium niobate by the Czochralski method, producing a transparent plate from the single crystal and producing an etalon from the transparent plate. There are provided etalons of thin type showing high thermal stability.

Abstract: A wavelength stabilized laser module is provided which is so configured as to be simplified and smaller in size and is capable of emitting semiconductor laser light whose wavelength is stablized with high accuracy. The wavelength stablized laser module includes a semiconductor laser, a substrate, a lens to convert emitted semiconductor laser light to parallel luminous flux, a first photoelectric converter to receive a part of the parallel luminous flux and to convert it to electric signals, a filter to receive a part of the parallel luminous flux, a second photoelectric converter to receive light transmitted through the filter and to convert it to electric signals, wherein a control signal to be used for stabilization obtained by computations of electric signals fed from the converters is fed back to the semiconductor laser device and/or the substrate so that said semiconductor laser is able to stably emit laser light having a reference wavelength to be used as a target for stabilization.

Abstract: An accelerometer is based upon the monolithic integration of a Fabry-Perot interferometer and a p+n silicon photosensor. Transmission of light through a Fabry-Perot interferometer cavity is exponentially sensitive to small displacements in a movable mirror due to an applied accelerating force. The photosensor converts this displacement into an electrical signal as well as provides for additional amplification. Because the interferometer and photosensor are monolithically integrated on a silicon substrate, the combination is compact and has minimal parasitic elements, thereby reducing the accelerometer's noise level and increasing its signal-to-noise ratio (SNR).

Abstract: A detunable Fabry-Perot interferometer, and method of tuning a Fabry-Perot interferometer are provided. The Fabry-Perot interferometer includes a first mirror, a second mirror oriented with respect to the first mirror so as to define a Fabry-Perot cavity therebetween, and an actuator configured to adjust a resonant wavelength of the Fabry-Perot cavity by varying a gap between the first and second mirrors, wherein the actuator is configured to selectively maintain the first and second mirrors in a substantially non-parallel relationship while the resonant wavelength of the Fabry-Perot interferometer is varied. The detunable Fabry-Perot interferometer can be employed in a multiplexer of a telecommunications system, as provided.

Abstract: Thin film filters have been a basic building block of many wavelength division multiplexed (WDM) systems providing the means by which a signal, defined by a center wavelength, can be separated from a group of WDM signals. In an effort to maintain the same performance over a range of operating temperatures, thin film filters have been coated onto specially designed substrates, which expand and contract with the change in temperature to counteract the effects that the temperature change has on the thin film filters. Unfortunately, only very few materials provide the necessary thermal expansion characteristics to counteract the shift in center wavelength. Moreover, the application of a force onto only one side of the filter causes the thin film filter to bend or curve. Accordingly, the present invention solves the aforementioned problems by providing a thin film filter sandwiched between a substrate and a superstrate, which apply equal forces to each side of the filter.

Abstract: The present invention discloses a Fabry-Perot optical filter device, which includes a Fabry-Perot element for allowing a light to pass through and optically filtering the light at least twice, and at least one reflecting element for reflecting the light passed through the Fabry-Perot element back to the same Fabry-Perot element during the at least two optical filtering. The Fabry-Perot optical filter device further includes an input terminal used to import the light into the Fabry-Perot optical filter device, and an output terminal used to export the light after the at least two optical filtering.

Abstract: A transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor and a method used for integrity monitoring of structures and measuring strain and temperature are provided. The transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor includes first single-mode optical fiber and second single-mode optical fiber, laser device, and optical detector. The first single-mode optical fiber is inserted into an end of a capillary quartz-glass tube and the second single-mode optical fiber is inserted into the other end of the capillary quartz-glass tube. Air gap is formed between the first single-mode optical fiber and the second single-mode optical fiber in the capillary quartz-glass tube. Gap length of the air gap changes in response to magnitude and direction of transformation of the capillary quartz-glass tube. The laser device launches light into an end of the first single-mode optical fiber.

Abstract: A method and an instrument are provided for checking and adjusting the accuracy of an alignment device which transmits a collimated (e.g. laser) light beam that serves as an alignment reference. That beam generator defines a precise reference for purposes of alignment of various other forms of apparatus, often over great distance. The checking and adjusting instrument (which is totally passive) provided by this invention is precisely attached to the alignment device, temporarily, and receives the reference beam of light from the device. The instrument displays an indication of misalignment of the beam, and also aids in correcting same.

Abstract: An accelerometer is based upon the monolithic integration of a Fabry-Perot interferometer and a p+n silicon photosensor. Transmission of light through a Fabry-Perot etalon is exponentially sensitive to small displacements in a movable mirror due to an applied accelerating force. The photosensor converts this displacement into an electrical signal as well as provides for additional amplification. Because the interferometer and photosensor are monolithically integrated on a silicon substrate, the combination is compact and has minimal parasitic elements, thereby reducing the accelerometer's noise level and increasing its signal-to-noise ratio (SNR).

Abstract: A tunable optical cavity constructed from a fixed mirror and a movable mirror is disclosed. A circuit applies an electrical potential between first and second electrically conducting surfaces thereby adjusting the distance between the fixed and movable mirrors. The fixed mirror and the moveable mirror are positioned such that the mirrors form the opposite ends of the optical cavity. The distance between the fixed mirror and the moveable mirror is a function of the applied electrical potential. The thermally induced vibrations are reduced by utilizing an electrical feedback circuit that measures the distance between the mirrors. The feedback circuit dynamically changes the potential between the substrate and the support member so as to reduce fluctuations in the cavity resonance frequency.