The Charles Stark Draper Laboratory, Inc.

Richard E Stoner

Stephen P Smith

David M S Johnson

William P Kelleher

David L Butts

Joseph M Kinast

Brian P Timmons

Juha-Pekka J Laine

Matthew A Sinclair

Adam F Kelsey

Reinhardt Leon Willig

Tom P Thorvaldsen

Jennifer T Choy

Timothy J McCarthy

Justin M Brown

Jacques P Govignon

Nicole Pomeroy

Nancy Wu

Adam J Saltzman

Antonije Radojevic

Krish Kotru

A fiber optical sensor and methods for sensing a physical quantity such as rotation using the same. The sensor has an optical fiber supporting propagation of light that is configured as an interferometer. One or more segments of the optical fiber, where the segments may be non-contiguous, are poled in such a manner that a phase shift in light propagating through the fiber is created in response to application of a voltage to an electrode thereby inducing an electric field across a poled segment of the fiber. A phase modulator comprising multiple poled segments is additionally described. Applying phase-shifting effects differentially across poled segments of optical fibers of an array of optical fibers may also allow for steering an optical beam.

Segmented poled optical fiber for fiber optic sensor and phased array

Methods and apparatus that provide for inertial sensing. In one example, a method for inertial sensing includes trapping and cooling a cloud of atoms, applying a first beam splitter pulse sequence to the cloud of atoms, applying one or more augmentation pulses to the cloud of atoms subsequent to applying the first beam splitter pulse sequence, applying a mirror sequence to the cloud of atoms, applying a one or more augmentation pulses to the cloud of atoms subsequent to applying the mirror sequence, applying a second beam splitter pulse sequence to the cloud of atoms subsequent to applying the second augmentation pulse, modulating at least one of a phase and an intensity of at least one of the first and the second beam splitter pulse sequences, performing at least one measurement on the cloud of atoms, and generating a control signal based on the at least one measurement.

Atom interferometry in dynamic environments

An atomic interferometer and methods for measuring phase shifts in interference fringes using the same. The atomic interferometer has a laser beam traversing an ensemble of atoms along a first path and an optical components train with at least one alignment-insensitive beam routing element configured to reflect the laser beam along a second path that is anti-parallel with respect to the first laser beam path. Any excursion from parallelism of the second beam path with respect to the first is rigorously independent of variation of the first laser beam path in yaw parallel to an underlying plane.

Separated parallel beam generation for atom interferometry

An inertial measurement apparatus based on atom interferometry. In one example, the inertial measurement apparatus includes a vacuum chamber, first and second atom capture sites housed within the vacuum chamber, each of the first and second atom capture sites being selectively configured to trap and cool first and second atom samples of distinct atom species, an atom interferometry region disposed between the first and second atom capture sites, and first and second atom interferometers operating in the atom interferometry region, the first atom interferometer being configured to generate a first measurement corresponding to a common inertial input based on the first atom sample, and the second atom interferometer being configured to generate a second measurement corresponding to the same common inertial input based on the second atom sample.

Systems and methods for multiple species atom interferometry

Compact inertial measurement systems and methods based on atom interferometry. Certain examples provide a combination atomic accelerometer-gyroscope configured to recapture and cycle atom samples through atom interferometers arranged to allow the next measurement to use the atoms from the previous measurement. Examples of the apparatus provide inertial measurements indicative of rotation for different inertial axes by applying atom interferometry to a plurality of atom samples launched in opposite directions to allow for measurement of both acceleration and rotation rates. In some examples, the inertial measurement apparatus provide a combined atomic gyroscope and an atomic accelerometer in a compact six Degrees of Freedom (6 DOF) IMU.

Ring architecture for sequential operation of an atomic gyroscope

Methods and apparatus for providing coherent atom population transfer using coherent laser beam pairs in which the frequency difference between the beams of a pair is swept over time. Certain examples include a Raman pulse adiabatic rapid passage sweep regimen configured to be used as a beamsplitter and combiner in conjunction with an adiabatic rapid passage mirror sweep or a standard Raman mirror pulse in a 3-pulse interferometer sequence.

Adiabatic rapid passage atomic beamsplitter using frequency-swept coherent laser beam pairs

Methods and apparatus that provide for precise and continuously-controlled generation of hyperfine polarizations and coherences in samples of laser cooled atoms. In one example, coherent population trapping induced by Raman pulses with preselected parameters (such as phase and duration) is employed as a mechanism for producing well-controlled atomic coherences and polarizations. In one example, these coherences and polarizations are used to provide precision polarization references for normalization of polarization readout measurements, and/or to provide precision phase references for phase storage or phase comparison.

Methods and apparatus for controlled generation of hyperfine polarizations and coherences

A fluorescence detection system includes a photonic band gap structure. An internal surface of the photonic band gap structure defines a core region, and is coated with a film formed of conjugated polymer molecules. The core region is filled with a sample fluid or gas having a plurality of either chemical or biological analytes dispersed therein. An optical source generates excitation light directed to the sample fluid. In response, a binding event between a bacterium or chemical species in the fluid or gas and one or more of the conjugated polymer molecules generates a fluorescent signal whose wavelength falls within the photonic band gap. The fluorescent signal is guided through said core region by resonant reflections, and is guided onto a detector. A plurality of photonic band gap structures may be combined so as to form a biosensor array.

Fluorescence detection system including a photonic band gap structure

An optical accelerometer for detecting an acceleration of a proof mass includes a source of optical radiation for generating a pair of beams of output radiation. The pair of beams of optical radiation exerts radiation pressure on the proof mass, so as to maintain the proof mass in an equilibrium position along a sensing axis. A position detecting system detects a displacement from the equilibrium position of the proof mass along the sensing axis in response to an inertial force acting on the proof mass. A modulator adjusts the intensity of each one of the pair of beams, so as to restore the proof mass to the equilibrium position along the sensing axis. The difference in the adjusted intensities of each one of the pair of beams is representative of the acceleration, resulting from the inertial force, of the proof mass along the sensing axis.

Optically rebalanced accelerometer

The invention relates to a method and system for wavelength stabilization of a broadband optical source. The method and system are based on utilizing an optical power divider to generate two optical signals for each of the broadband source and a reference wavelength source. The difference in the power ratio of the two optical signals derived from the broadband source and the power ratio of the two optical signals derived from the reference wavelength source is determined. Because the power ratios are similarly affected by component aging and changes in environmental factors such as temperature and incident radiation, the difference in the power ratios can be used to adjust the wavelength of the broadband source so that its center wavelength is stabilized to the center wavelength of the reference source.

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Framingham, MA, United States of America

Richard E Stoner