Craig W Hodgson

US Patent:

6365891, Apr 2, 2002

Filed:

Jun 29, 2000

Appl. No.:

09/606771

Inventors:

Craig W. Hodgson - Thousand Oaks CA
Jefferson L. Wagener - Charlottesville VA
Michel J. F. Digonnet - Palo Alto CA
H. John Shaw - Stanford CA

Assignee:

Board of Trustees of the Leland Stanford Junior University - Stanford CA

International Classification:

G01J 104

US Classification:

25022714, 25022719

Abstract:

The present invention significantly improves the signal to noise ratio (SNR) in a passive optical array comprising sensors located in rungs between a distribution bus and a return bus. Erbium-doped optical fiber amplifiers are included in the buses proximate to each rung coupling to offset the coupler splitting losses. The gains of the amplifiers are selected to offset losses due to the couplings. The overall SNR can be maintained without significant degradation even for large numbers of sensors. In one aspect of the present invention, the amplifiers are located along the distribution and return buses directly after the couplers, except for the last coupler. In a second aspect, the amplifiers are located directly before each coupler. The optical amplifiers preferably are made of short lengths of erbium-doped fiber spliced into the distribution and return buses. Improvements can be made to the SNR when the distribution bus coupling ratios are set at optimal values.

US Patent:

6507679, Jan 14, 2003

Filed:

May 13, 1999

Appl. No.:

09/311030

Inventors:

Craig W. Hodgson - Thousand Oaks CA
Donald A. Frederick - Simi Valley CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

G02B 600

US Classification:

385 12, 356478

Abstract:

An optical sensor architecture receives an input optical signal from a signal source and outputs a perturbed optical signal from at least one sensor to a receiver. An optical amplifier is positioned along a return fiber at an optical distance at least 10 kilometers from the receiver, with the optical amplifier amplifying the perturbed optical signal propagating to the receiver. If only one optical amplifier is used, the optical distance between the amplifier and the receiver may be between about 10 km and about 80 km, and an optical distance of between about 10 km and about 150 km may separate the sensor and the receiver. If additional optical amplifiers and dedicated pump distribution fibers are used, the optical distances may be correspondingly greater. Alternatively, increasing the number of sensors necessitates a reduction in the optical distance separating the sensors from shore.

US Patent:

6728165, Apr 27, 2004

Filed:

Oct 29, 1999

Appl. No.:

09/429048

Inventors:

John A. Roscigno - Stevenson Ranch CA
Craig W. Hodgson - Thousand Oaks CA
Donald A. Frederick - Simi Valley CA
William C. Knaack - West Hills CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

G01V 100

US Classification:

367 14, 367149, 181102, 3408547, 3408553, 3408555

Abstract:

A system for sensing subterranean acoustic waves emitted from an acoustic source includes a plurality of laser sources, a plurality of subterranean optical sensors, at least one optical detector, and electronics. The laser sources each emit light at a different frequency. The subterranean optical sensors receive the light and alter the light in response to the acoustic waves. The optical detector receives the altered light and outputs an electrical signal. The electronics receives the electrical signal and converts it into seismic data format. The hydrophone for sensing the acoustic signals is able to operate at pressures of at least 5,000 psi and temperatures of at least 130 degrees Celsius. A hydrophone may be housed in a cable having a diameter of less than about 1. 5 inches. The hydrophones sensor preferably includes a reference mandrel, two sensing mandrels, and a telemetry can, all of which are aligned in a coaxial, end-to-end configuration to reduce the profile of the hydrophone.

US Patent:

7054521, May 30, 2006

Filed:

Jun 9, 2004

Appl. No.:

10/864656

Inventors:

Craig W. Hodgson - Thousand Oaks CA, US
Donald A. Frederick - Woodland Hills CA, US

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

G02B 6/28
G02B 6/26
G01J 1/04
G01J 1/42

US Classification:

385 24, 385 15, 385 31, 385 39, 25022712, 25022714, 25022718, 25022727

Abstract:

Sensor arrays utilizing standard 1×2 couplers reduce the differences in the returned optical power levels by appropriate selection of the coupling ratios. Preferred embodiments are described that comprise 6 distribution fiber lines and 16 return fiber lines. One embodiment includes 16 sensor groups in which each sensor group has a dedicated return line. In another embodiment, 8 sensor groups are configured so that no two adjacent sensors have either a common distribution fiber line or a common return fiber line.

US Patent:

7083333, Aug 1, 2006

Filed:

Aug 29, 2003

Appl. No.:

10/652093

Inventors:

Craig W. Hodgson - Thousand Oaks CA, US

Assignee:

Intel Corporation - Santa Clara CA

International Classification:

G02B 6/36

US Classification:

385 79, 385 53, 385 76, 385 77, 385 78

Abstract:

Housings for use in optical packages, optical packages, and methods to manufacture the same are disclosed. A disclosed optical assembly includes a housing having a ferrule to receive an optical fiber; a lens; an annular mechanical interface; and a total internal reflection surface disposed between the ferrule and the lens to direct light between the ferrule and the lens. The example optical package also includes an optical element coupled to the mechanical interface of the housing to form a sealed chamber. The lens is disposed within the sealed chamber substantially in optical alignment with the optical element.

US Patent:

7773300, Aug 10, 2010

Filed:

Jan 8, 2007

Appl. No.:

11/650441

Inventors:

Craig Hodgson - Fairport NY, US
Turan Erdogan - Spencerport NY, US
Ligang Wang - Rochester NY, US

Assignee:

Semrock, Inc. - Rochester NY

International Classification:

G02B 1/10

US Classification:

359588, 359586

Abstract:

An optical filter is provided which includes a plurality of hard coating layers of alternating high and low refractive index provided on a substrate and has an associated first transmission band. The filter also includes at least one additional plurality of hard coating layers including high and low refractive index layers and Herpin equivalent layers sandwiched therebetween. The additional plurality of layers has an associated second transmission band that substantially coincides with the first transmission band, but provides additional blocking at wavelengths outside the first transmission band. Relatively wide transmission bands and high blocking over an extended range of wavelengths can be achieved such that the filter is suitable for use in multiphoton fluorescence systems.

US Patent:

8508849, Aug 13, 2013

Filed:

Jul 19, 2010

Appl. No.:

12/839040

Inventors:

Craig Hodgson - Fairport NY, US
Turan Erdogan - Spencerport NY, US
Ligang Wang - Rochester NY, US

Assignee:

Semrock, Inc. - Rochester NY

International Classification:

G02B 5/28

US Classification:

359589

Abstract:

An optical filter is provided which includes a plurality of hard coating layers of alternating high and low refractive index provided on a substrate and has an associated first transmission band. The filter also includes at least one additional plurality of hard coating layers including high and low refractive index layers and Herpin equivalent layers sandwiched therebetween. The additional plurality of layers has an associated second transmission band that substantially coincides with the first transmission band, but provides additional blocking at wavelengths outside the first transmission band. Relatively wide transmission bands and high blocking over an extended range of wavelengths can be achieved such that the filter is suitable for use in multiphoton fluorescence systems.

US Patent:

20010014192, Aug 16, 2001

Filed:

Apr 2, 2001

Appl. No.:

09/824119

Inventors:

Craig Hodgson - Thousand Oaks CA, US
Donald Frederick - Woodland Hills CA, US

International Classification:

G02B006/26

US Classification:

385/012000, 385/015000

Abstract:

Sensor arrays utilizing standard 1×2 couplers reduce the differences in the returned optical power levels by appropriate selection of the coupling ratios. Preferred embodiments are described that comprise 6 distribution fiber lines and 16 return fiber lines. One embodiment includes 16 sensor groups in which each sensor group has a dedicated return line. In another embodiment, 8 sensor groups are configured so that no two adjacent sensors have either a common distribution fiber line or a common return fiber line.