Scott C Rashleigh

US Patent:

44202580, Dec 13, 1983

Filed:

Oct 23, 1981

Appl. No.:

6/314298

Inventors:

William K. Burns - Alexandria VA
Scott C. Rashleigh - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01C 1964
G01B 902

US Classification:

356350

Abstract:

A fiber-optic gyroscope designed to operate at maximum sensitivity by suping two equal-intensity input beams with a specific phase difference to the gyroscope optical coupler. When the coupler outputs into the gyroscope optical fiber coil are of equal intensity, reciprocity requires the gyroscope to operate at quadrature. This device is realized by splitting a laser beam into two paths with a phase shifter in one of the paths to control the phase shift and thereby the intensity of the beams, and coupling the light from these paths into a fiber optic coil via a four-port 3dB coupler.

US Patent:

45360880, Aug 20, 1985

Filed:

Sep 17, 1982

Appl. No.:

6/419257

Inventors:

Scott C. Rashleigh - Alexandria VA
Samuel J. Petuchowski - Bethesda MD

International Classification:

G01B 902

US Classification:

356351

Abstract:

A polarimetric Fabry-Perot sensor comprising a source of coherent polarized light, an optical cavity, preferably an optical fiber, capable of supporting two independent modes of that light and coated with partially reflecting material on both ends, a sensing element for detecting the external field that differentially affects the two modes, and means for measuring interference between the two modes.

US Patent:

44423500, Apr 10, 1984

Filed:

Aug 17, 1981

Appl. No.:

6/293589

Inventors:

Scott C. Rashleigh - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01B 1116

US Classification:

250227

Abstract:

A sensor is provided for sensing or detecting the presence of an environmental field condition such as acceleration, temperature change, magnetic or acoustic fields. The field is sensed by interference between two mutually orthogonal polarized eigenmodes in a single monomode optical fiber which may be disposed either linearly or wound on a mandrel made of compliant material for sensing an acoustic field, or made of magnetostrictive material for sensing a magnetic field. Polarized light propagated through the optical fiber is detected at its outlet independent of environmentally induced low frequency variations whereby the sensor may be maintained at quadrature and maximum sensitivity.

US Patent:

44914130, Jan 1, 1985

Filed:

Apr 22, 1982

Appl. No.:

6/370755

Inventors:

Scott C. Rashleigh - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01C 1964
G01B 902

US Classification:

356350

Abstract:

A Sagnac rotation sensing interferometer that uses a Mach-Zehnder interferometer to provide incident light beams that counter-propagate through an optical-fiber loop. The Sagnac interferometer operates at maximum sensitivity for zero rotation rates when the Mach-Zehnder is adjusted so that the intensities of the incident light beams are equal. By peiodically varying the position of a mirror in the Mach-Zehnder the interferometer is switched into and out of quadrature so that the amplitude of the interferometer output signal is modulated at frequency f. sub. o. Phase sensitive detection at 2f. sub. o or multiples thereof reduces the background noise level several orders of magnitude below the level for dc operation.

US Patent:

46662553, May 19, 1987

Filed:

Jun 12, 1986

Appl. No.:

6/873488

Inventors:

Henry F. Taylor - Alexandria VA
Scott C. Rashleigh - Alexandria VA
Joseph F. Weller - Fort Washington MD
Kiyoshi Nosu - Yokosuka, JP

Assignee:

Sachs/Freeman Associates, Inc. - Bowie MD

International Classification:

G02B 530
G02B 626
G02B 602
G02F 101

US Classification:

350371

Abstract:

An acousto-optic frequency shifter in which two cylindrical acoustic resonators driven 90. degree. out of phase from one another are placed around a birefringent, single-mode optical fiber approximately three-quarters of a polarization beat length apart. The resonators interact with optical radiation propagating in one of two polarization modes of the fiber, the first to cross-couple two sidebands into the other polarization mode, and the second to suppress one of the sidebands in the cross-coupled mode and enhance the other, thereby creating a single sideband signal completely within the fiber.

US Patent:

45395195, Sep 3, 1985

Filed:

Apr 23, 1982

Appl. No.:

6/371203

Inventors:

Reinhard Ulrich - Buchholz, DE
Scott C. Rashleigh - Alexandria VA

Assignee:

Max-Planck-Gesellschaft zur Forderung der Wissenschaften e.V.

International Classification:

G01R 3300
G01R 1900

US Classification:

324117R

Abstract:

In order to measure the intensity of an electric current utilizing the Faay effect, an optical path which is exposed to a magnetic field generated by the current is marked by an optical fiber which is laid in a number of windings in the shape of a coil. In order to minimize the disruptive effect of, for instance, elliptical eigen-birefringence of the fiber, or birefringence caused by the laying of the fiber on the zero point and the calibration factor of the device, the end of the optical fiber which is away from the input point is provided with a reflection unit which reflects back into the fiber the light which arrives there with the same polarization state with which it arrived at the reflection unit. A polarization measurement unit is used to record the polarization state of light flux which, after having traversed the optical fiber a total of twice, again emerges at the input point. The current intensity can then be derived from the change in the polarization state compared to the light which was input into the optical fiber at the input point.

US Patent:

44954115, Jan 22, 1985

Filed:

Oct 27, 1982

Appl. No.:

6/437098

Inventors:

Scott C. Rashleigh - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01D 534

US Classification:

250227

Abstract:

A fiber optic sensor for detecting and/or measuring a physical quantity varying at any frequency from a maximum desired frequency down to zero frequency with minimum disturbance from environmentally induced perturbations. A first highly birefringent optical fiber is positioned longitudinally adjacent to a second equally birefringent fiber. Each fiber has orthogonally disposed fast and slow axes. The fibers are oriented such that their fast axes are perpendicular to each other. When subjected to stress caused by a physical quantity acting on the fibers through a transducer, the birefringence of each of the two fibers is asymmetrical altered thereby rotating the states of polarization of coherent light signals passing through the two fibers in a common direction. Environmental perturbations symmetrically alter the birefringence of each of the fibers thereby rotating the states of polarization of the light signals in opposite directions. The states of polarization of the light signals emanating from the two fibers are detected and combined such that the changes due to the physical quantity enhance each other while the changes due to environmental perturbations are cancelled.

US Patent:

44680902, Aug 28, 1984

Filed:

Jul 20, 1981

Appl. No.:

6/284791

Inventors:

Reinhard Ulrich - 2110 Buchholz, DE
Scott Rashleigh - Alexandria VA

International Classification:

G02B 5172

US Classification:

350 9630

Abstract:

A fiber optical arrangement for the transmission, in a manner preserving its polarization, of light of a linear polarization state using an optical fiber having a linear birefringence of an amount sufficient to provide extensive decoupling of the polarization-degenerate modes of oscillation of the light that can propagate within the fiber. The amount of linear birefringence. beta. required for decoupling these modes of oscillation is achieved by winding the optical fiber in an elastically extended condition upon a winding form and fixing it thereon in this elastically extended state, the linear birefringence. beta. =. beta. sub. tc +. beta. sub. b being preferably three times greater than the intrinsic birefringence. beta. sub. i of the optical fiber. The fiber optical arrangement may be used within an interferometer for measuring pressures or, if mounted to rotate, within a Sagnac interferometer also for the exact measurement of rotations and rates of angular displacements.