Michael J Marrone

US Patent:

49327836, Jun 12, 1990

Filed:

Jul 21, 1989

Appl. No.:

7/383390

Inventors:

Alan D. Kersey - Springfield VA
Michael J. Marrone - Severna Park MD

Assignee:

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

International Classification:

G01B 902

US Classification:

356345

Abstract:

An apparatus for minimizing polarization-induced signal fading in an interferometric fiber-optic sensor is disclosed. The apparatus includes an optical source for providing an input light beam, a polarization modulator for modulating the state of polarization of the input light beam into at least three states represented by mutually perpendicular polarization vectors on a Poincare Sphere. The apparatus further includes means for conveying the input light beam with the at least three mutually perpendicular modulated states of polarization to the fiber-optic sensor, the interferometric fiber-optic sensor being responsive to the input light beam with modulated polarization states for developing an interference pattern output, wherein the interference pattern output has at least three visibilities corresponding to the input states of polarization. A photodetector is responsive to the interference pattern output for developing an electrical signal having at least three amplitudes corresponding to the at least three states of polarization. An output circuit is responsive to the electrical photodetector signal for time-sampling the photodetector signal having three amplitudes corresponding to the at least three mutually perpendicular input states of polarization and selecting the one having maximum visibility.

US Patent:

54345014, Jul 18, 1995

Filed:

Apr 29, 1994

Appl. No.:

8/235842

Inventors:

Ronald D. Esman - Burke VA
Alan D. Kersey - Fairfax Station VA
Michael J. Marrone - Severna Park MD

Assignee:

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

International Classification:

G01R 3332

US Classification:

324 96

Abstract:

A sensor system includes a sensor head, an optical source, and a measurement apparatus. The sensor head includes a beamsplitter having first, second, third, and fourth ports, the beamsplitter being responsive to light selectively applied to the first, second and third ports for passing light of a first polarization state from the first port to the second port, for passing light of a second polarization state from the first port to the third port, for passing light of the second polarization state from the second port to the fourth port, and for passing light of the first polarization state from the third port to the fourth port. The optical source means provides light to the first port. The sensor head further includes a bidirectional polarimetric sensor responsive to polarized light output by the beamsplitter at the second and third ports and to an electromagnetic field applied to the polarimetric sensor for producing first polarized light at said third port and for producing second polarized light at said second port. The first and second polarized light have polarization states each of which varies as a function of the electromagnetic field and the polarization state of the light output by the beamsplitter at the other one of the second and third ports.

US Patent:

54404142, Aug 8, 1995

Filed:

Feb 2, 1990

Appl. No.:

7/473807

Inventors:

Alan D. Kersey - Springfield VA
Michael J. Marrone - Severna Park MD

Assignee:

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

International Classification:

G02B 530

US Classification:

359122

Abstract:

A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are evolved such that there are equal signal to reference power ratios on the beam splitter axes, subsequent detectors generate a constant, optimum amplitude signal without the need for weighting or decision circuits.

US Patent:

51042223, Apr 14, 1992

Filed:

Sep 18, 1990

Appl. No.:

7/584221

Inventors:

Alan D. Kersey - Springfield VA
Michael J. Marrone - Severna Park MD
Anthony Dandridge - Alexandria VA

Assignee:

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

International Classification:

G01B 902

US Classification:

356345

Abstract:

A system and method for minimizing polarization-induced phase noise in an interferometric fiber sensor is disclosed. The system includes an optical source of light; a single mode input fiber; means coupled between the optical source and the input fiber for scrambling the polarization state of the light from the optical source at a first frequency to effectively produce and pass depolarized light to the input fiber; an interferometric fiber sensor responsive to light from the input fiber for producing at its output an interference pattern proportional to a phase shift produced by a field being sensed by the interferometric fiber sensor; detection means responsive to the interference pattern for developing a photocurrent signal averaged over a period of time longer than the period of the first frequency; and demodulation means responsive to the photocurrent signal for producing an electrical output signal substantially proportional to the phase shift produced by the field being sensed by the interferometric sensor.

US Patent:

54790948, Dec 26, 1995

Filed:

Apr 24, 1995

Appl. No.:

8/427461

Inventors:

Ronald D. Esman - Burke VA
Alan D. Kersey - Fairfax Station VA
Michael J. Marrone - Severna Park MD

Assignee:

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

International Classification:

G01R 3332

US Classification:

324 96

Abstract:

A sensor system includes a sensor head, an optical source, and a measurement apparatus. The sensor head includes a beamsplitter having first, second, third, and fourth ports, the beamsplitter being responsive to light selectively applied to the first, second and third ports for passing light of a first input polarization state from the first port to the second port, for passing light of a second input polarization state orthogonal to the first input polarization state from the first port to the third port, and for collectively passing light of a first output polarization state and light of a second output polarization state orthogonal to the first output polarization state from the third port to the fourth port. The optical source means provides light to the first port. The sensor head further includes a bidirectional polarimetric sensor responsive to polarized light output by the beamsplitter at the second and third ports and to an electromagnetic field applied to the polarimetric sensor for producing first polarized light at said third port and for producing second polarized light at said second port.

US Patent:

59867841, Nov 16, 1999

Filed:

Dec 12, 1994

Appl. No.:

8/354931

Inventors:

Alan D. Kersey - Springfield VA
Michael J. Marrone - Severna Park MD
Anthony Dandridge - Alexandria VA

Assignee:

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

International Classification:

G02B 530

US Classification:

359122

Abstract:

A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are evolved such that there are equal signal to reference power ratios on the beam splitter axes, subsequent detectors generate a constant, optimum amplitude signal without the need for weighting or decision circuits.