Mark Douglas Weber

US Patent:

7218402, May 15, 2007

Filed:

Dec 4, 2003

Appl. No.:

10/727473

Inventors:

Stephen John Brosnan - San Pedro CA, US
Mark Ernest Weber - Hawthorne CA, US

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

G01B 11/02

US Classification:

356484

Abstract:

A hybrid optical/electronic wavefront sensor includes an electro-acoustical device used to upshift an optical reference signal. An optical test signal and the frequency upshifted optical reference signal are optically heterodyned to create a signal having a frequency equivalent to the beat frequency of the two signals, for example, the RF driving frequency of the Bragg cell. The optically heterodyned signal is then converted by way of a detector to an electronic signal having the same phase as the optical test signal. The output of the detector is a sinusoidal signal having the same phase as the phase of the optical test signal. This signal is filtered by way of an AC filter and mixed with a second clock signal, for example, a clock signal that is offset in frequency from the electro-acoustical drive signal by a frequency, for example, between 100 kHz and 1 MHz. These two signals are mixed by way of a mixer. The low frequency product of the mixer is passed by way of a filter and converted to a square wave by way of a comparator.

US Patent:

20130105674, May 2, 2013

Filed:

Mar 13, 2012

Appl. No.:

13/419054

Inventors:

Gregory D. Goodno - Los Angeles CA, US
Mark E. Weber - Hawthorne CA, US

Assignee:

Northrop Grumman Systems Corporation - Falls Church VA

International Classification:

G01J 1/04
G02F 1/01

US Classification:

25022711, 250225

Abstract:

A multichannel polarization stabilizer including a mixing device responsive to a sample beam and a reference beam that provides an in-phase signal including the mixed sample beam and reference beam having a relative phase of 0 and a quadrature phase signal including the mixed sample beam and reference beam having a relative phase of 90. The stabilizer also includes a photodetector responsive to the quadrature phase signal that converts the quadrature phase signal to a quadrature phase electrical signal. A polarization demultiplexer circuit receives the quadrature phase electrical signal and measures the amplitude of a frequency tone in the sample beam and provides a polarization amplitude signal. A polarization controller receives the polarization amplitude signal and controls the reference beam to maximize the polarization amplitude signal.