Alan Braun

US Patent:

7164699, Jan 16, 2007

Filed:

Jun 1, 2004

Appl. No.:

10/859553

Inventors:

Alan Michael Braun - Lawrenceville NJ, US
Joseph H. Abeles - East Brunswick NJ, US
Martin H. Kwakernaak - New Brunswick NJ, US
Viktor Borisovitch Khalfin - Hightstown NJ, US

Assignee:

Sarnoff Corporation - Princeton NJ

International Classification:

H01S 3/13

US Classification:

372 29022

Abstract:

A low-jitter optical pulse source including: a monolithic waveguide including a first section substantially perpendicular to a first facet and a second section being curved and substantially non-perpendicular to a second facet; and, an optical circulator coupled to the monolithic waveguide and forming a sigma cavity in combination with the monolithic waveguide, wherein the first facet forms a sole reflector for the sigma cavity.

US Patent:

7468637, Dec 23, 2008

Filed:

Apr 18, 2007

Appl. No.:

11/736657

Inventors:

Alan Michael Braun - Lawrenceville NJ, US
Joseph Hy Abeles - East Brunswick NJ, US
Winston Kong Chan - Princeton NJ, US
Martin Kwakernaak - New Brunswick NJ, US
Timothy James Davis - Columbus NJ, US

Assignee:

Sarnoff Corporation - Princeton NJ

International Classification:

H01S 1/06
H03L 7/26

US Classification:

331 941, 331 3

Abstract:

A chip scale atomic clock is disclosed that provides a low power atomic time/frequency reference that employs direct RF-interrogation on an end-state transition. The atomic time/frequency reference includes an alkali vapor cell containing alkali atoms, preferably cesium atoms, flex circuits for physically supporting, heating, and thermally isolating the alkali vapor cell, a laser source for pumping alkali atoms within the alkali vapor cell into an end resonance state by applying an optical signal along a first axis, a photodetector for detecting a second optical signal emanating from the alkali vapor cell along the first axis, a pair of RF excitation coils for applying an RF-interrogation signal to the alkali atoms along a second axis perpendicular to the first axis, a pair of bias coils for applying a uniform DC magnetic field along the first axis, and a pair of Zeeman coils for applying a Zeeman interrogation signal to the alkali atoms and oriented and configured to apply a time-varying magnetic field along the second axis through the alkali vapor cell. Another flex circuit is used for physically supporting the laser source, for heating the laser source, and for providing thermal isolation of the laser source. The laser source can be a vertical cavity surface emitting laser (VSCEL).

US Patent:

7852163, Dec 14, 2010

Filed:

Nov 19, 2008

Appl. No.:

12/273852

Inventors:

Alan Michael Braun - Lawrenceville NJ, US
Joseph Hy Abeles - East Brunswick NJ, US
Winston Kong Chan - Princeton NJ, US
Martin Kwakernaak - New Brunswick NJ, US
Timothy James Davis - Columbus NJ, US

Assignee:

Sarnoff Corporation - Princeton NJ

International Classification:

H01S 1/06
H03L 7/26

US Classification:

331 941, 331 3

Abstract:

A chip scale atomic clock is disclosed that provides a low power atomic time/frequency reference that employs direct RF-interrogation on an end-state transition. The atomic time/frequency reference includes an alkali vapor cell containing alkali atoms, preferably cesium atoms, flex circuits for physically supporting, heating, and thermally isolating the alkali vapor cell, a laser source for pumping alkali atoms within the alkali vapor cell into an end resonance state by applying an optical signal along a first axis, a photodetector for detecting a second optical signal emanating from the alkali vapor cell along the first axis, a pair of RF excitation coils for applying an RF-interrogation signal to the alkali atoms along a second axis perpendicular to the first axis, a pair of bias coils for applying a uniform DC magnetic field along the first axis, and a pair of Zeeman coils for applying a Zeeman interrogation signal to the alkali atoms and oriented and configured to apply a time-varying magnetic field along the second axis through the alkali vapor cell. Another flex circuit is used for physically supporting the laser source, for heating the laser source, and for providing thermal isolation of the laser source. The laser source can be a vertical cavity surface emitting laser (VSCEL).

US Patent:

7902927, Mar 8, 2011

Filed:

Jun 18, 2009

Appl. No.:

12/487400

Inventors:

Timothy Davis - Columbus NJ, US
Sterling McBride - Princeton NJ, US
Alan Braun - Lawrenceville NJ, US
William Happer - Princeton NJ, US

Assignee:

SRI International - Menlo Park CA

International Classification:

H03L 7/26
H03L 1/02
H03B 17/00

US Classification:

331 3, 331 941, 331176

Abstract:

The present invention provides a system and method for achieving a calibration-free primary atomic clock standard operating at the 0-0 transition free-atom frequency, thus creating a primary frequency standard, with attributes that include scalable to chip-scale dimensions and power consumption.

US Patent:

20050265407, Dec 1, 2005

Filed:

May 16, 2005

Appl. No.:

11/130038

Inventors:

Alan Braun - Lawrenceville NJ, US
Peter Delfyett - Geneva FL, US

International Classification:

H01S003/10

US Classification:

372030000

Abstract:

A compact signal source including: a semiconductor-based, pulsed optical energy source for providing a series of pulses at a given frequency; a selector being optical fiber coupled to the pulsed optical energy source and for down-selecting the pulses to a lower frequency; a stretcher being optical fiber coupled to the selector and for temporally stretching the selected pulses; at least one semiconductor-based optical amplifier being optical fiber coupled to the stretcher and for amplifying the selected pulses; a compressor being optical fiber coupled to the at least one semiconductor-based amplifier and for temporally compressing the amplified, stretched, selected pulses; and, a portable housing containing the pulsed optical energy source, stretcher, at least one semiconductor-based optical amplifier and compressor.

US Patent:

20090059980, Mar 5, 2009

Filed:

Mar 17, 2008

Appl. No.:

12/050152

Inventors:

Alan M. Braun - Lawrenceville NJ, US
Joseph H. Abeles - East Brunswick NJ, US

International Classification:

H01S 3/098

US Classification:

372 3801

Abstract:

Embodiments of the invention are directed to an atomic-based frequency reference that includes an architecture that eliminates the need for local oscillator components and instead is implemented with a “photonic local oscillator,” that provides for a relatively low power consumption, compact, atomic clock/frequency reference. Such a system is based on a laser cavity which contains an alkali-vapor-cell within the laser cavity. The laser cavity is designed to oscillate in two or more optical wavelengths, with the frequency difference of these lasing wavelengths equal to the atomic hyperfine resonance frequency. Embodiments of the system can include relatively few elements, namely: a) an optical gain element with an emission band centered at the atomic absorption band; b) collimating optics; c) an atomic vapor cell; and d) a cavity end mirror. Optionally, specific polarization optics may be used depending on the specifics of the optical pumping.