Frank F Adams

US Patent:

6654391, Nov 25, 2003

Filed:

Mar 30, 2001

Appl. No.:

09/823908

Inventors:

Frank Adams - Los Altos CA

Assignee:

Lightwave Electronics - Mountain View CA

International Classification:

H01S 310

US Classification:

372 10, 372 12, 372 13, 372 25, 372 29021, 372 30, 372 70

Abstract:

An intracavity frequency converted, Q-switched laser and method for operating such laser to obtain high output power in secondary pulses at a converted frequency. The secondary pulses are generated by a intracavity frequency conversion element from primary pulses at the fundamental wavelength. In accordance with the invention, after the primary and secondary pulses are generated the Q-switch is turned back on before the gain is fully depleted in the generation of the primary pulse. In particular, the Q-switch is turned back on such that a certain amount of energy of the primary pulse is retained in the laser, but late enough so that a majority of the secondary pulse is out-coupled from the laser. The Q-switched laser is well-suited for use at pulse repetition rates larger than 1/ , where is an upper state lifetime (fluorescence lifetime) of the laser. Specifically, the laser can be operated at repetition rates of 10 kHz and higher, e. g.

US Patent:

6807203, Oct 19, 2004

Filed:

Dec 5, 2001

Appl. No.:

10/006786

Inventors:

Frank J. Adams - Los Altos CA

Assignee:

Lightwave Electronics Corporation - Mountain View CA

International Classification:

H01S 313

US Classification:

372 32, 372 28

Abstract:

Methods and apparatus for calibrating a frequency difference between two or more lasers over an extended frequency range as well as optical signal generators that employ such an apparatus or method are disclosed. The lasers are tuned in coordination with respect to one or more readily characterized narrow frequency ranges to characterize one or more tuning parameters of each of the lasers over the extended frequency range. The apparatus may include first and second tuning controllers respectively coupled to the first and second lasers, an optical coupler optically coupled to the first laser and the second laser, a frequency detector coupled to the optical coupler and a controller coupled to the frequency detector and the temperature controllers. The controller may include a processor and a memory containing processor executable instructions for calibrating the two lasers in accordance with the method described above. Such a frequency calibration apparatus may be incorporated with the lasers into a signal generator apparatus.

US Patent:

7352784, Apr 1, 2008

Filed:

Jul 20, 2004

Appl. No.:

10/896641

Inventors:

Frank J. Adams - Los Altos CA, US
Mark A. Arbore - Los Altos CA, US
Werner H. Wiechmann - San Jose CA, US

Assignee:

JDS Uniphase Corporation - Milpitas CA

International Classification:

H01S 3/04

US Classification:

372 34, 372 29011

Abstract:

Methods and apparatus for managing thermal loads on a laser gain medium and for boosting the output power of a diode pumped laser are disclosed. The short-term average pumping power to the gain medium is increased, to provide a burst of pumping energy to the laser gain medium. A subsequent short-term reduction in the average pumping power then allows the gain medium to cool to a desired state steady level. The average pumping power is then increased to maintain this steady state level until the next burst is desired. For example, a pulse of current may be applied to a laser diode at a first current level Ifor a first time interval Δt, where Iexceeds a nominal current value Iby an amount ΔI. The current to the laser diode is reduced to a second current level Ifor a second time interval Δt, where Iexceeds Iby an amount ΔI. To balance the thermal load on the diode an integral of ΔIover the time Δtis approximately equal in magnitude to an integral of ΔIover the time Δt.

US Patent:

7622912, Nov 24, 2009

Filed:

Jun 10, 2008

Appl. No.:

12/136698

Inventors:

Frank J. Adams - Los Altos CA, US
David L. Klein - Palo Alto CA, US

Assignee:

Sunpower Corporation - San Jose CA

International Classification:

G01R 31/28

US Classification:

3241581, 324142, 324107, 324117 H, 307 44, 307 45, 307 64

Abstract:

Power consumption at a site is monitored. An electrical load is connected to a power source by an electrical conductor. A fuel-less energy producing device is electrically connected to a junction along the electrical conductor. A current sensor is electromagnetically coupled to the electrical conductor at a sensing position between the power source and the junction to create a current sensor signal. Sensed current and voltage signals are produced from the current sensor signal. A sensed phase relationship between the sensed signals is determined and compared to a baseline phase relationship to determine the direction of current flow through the conductor. A power source signal, based on the current flowing through the conductor at the sensing position, is created. With some examples a Rogowski type differential current sensor is used. In some examples a single current sensor is used.

US Patent:

8160113, Apr 17, 2012

Filed:

Jul 21, 2009

Appl. No.:

12/506849

Inventors:

Frank J. Adams - Los Altos CA, US
Manuel J. Leonardo - San Francisco CA, US
David L. Klein - Palo Alto CA, US

Assignee:

Mobius Photonics, Inc. - Mountain View CA

International Classification:

H01S 3/10

US Classification:

372 25, 372 26, 372 29015, 372 29011, 372 2901

Abstract:

Output pulses from an optical system having a seed source and an optical amplifier coupled to the seed source may be controlled by controlling a power of a seed signal from the seed source. The seed signal may be varied between a minimum value and a maximum value in a way that the seed signal exhibits one or more pulse bursts. Each pulse burst may contain one or more pulses. During an inter-pulse period between successive pulses within a pulse burst or between successive pulse bursts, the power of the seed signal may be adjusted to an intermediate value that is greater than the minimum value and less than the maximum value. The intermediate value is chosen to control a gain in the optical amplifier such that a pulse or pulse burst that follows the period exhibits a desired behavior.

US Patent:

20050212357, Sep 29, 2005

Filed:

Mar 23, 2004

Appl. No.:

10/806686

Inventors:

Frank Adams - Edison NJ, US

International Classification:

B60T008/88

US Classification:

303122030, 18800111L

Abstract:

A vehicle brake having a brake monitoring and sensor system attached to a brake shoe of a brake assembly for monitoring of temperature and wear of a brake shoe lining of a vehicle. The vehicle brake monitoring and sensor system includes a brake assembly for frictional braking of a vehicle. The brake assembly includes a brake shoe lining having a brake shoe and a brake pad for frictional engagement with the brake assembly; and the brake shoe lining has first rivet openings with rivets therein, and has second rivet openings with no rivets therein. The vehicle brake monitoring system also includes a sensor system having a first sensing element and a second sensing element each connected to the brake shoe; the first sensing element is embedded in one or more of the first rivet openings with the rivets therein; and the second sensing element is embedded in one or more of the second rivet openings having no rivets therein. The first sensing element is for generating a first electrical signal in response to sensing changes in the temperature of the brake shoe generated by heat in the brake shoe and transmitted to one or more rivets in the first rivet openings. The second sensing element is for generating a second electrical signal in response to sensing a predetermined depth of wear of the brake pad. The vehicle brake monitoring and sensor system further includes a monitoring unit for processing the first and second electrical signals generated by the first and second sensing elements.

US Patent:

D2532751, Oct 30, 1979

Filed:

Nov 11, 1977

Appl. No.:

5/850859

Inventors:

Frank J. Adams - La Canada CA

International Classification:

D0708

US Classification:

D 7208

US Patent:

52260518, Jul 6, 1993

Filed:

Jun 4, 1991

Appl. No.:

7/710288

Inventors:

Melvin Chan - Daly City CA
Henry G. Plaessman - Mountain View CA
Frank Adams - San Leandro CA
William M. Grossman - Los Altos CA

Assignee:

Lightwave Electronics - Mountain View CA

International Classification:

H01S 313

US Classification:

372 30

Abstract:

Method and apparatus for stabilization of pulse energies produced by a continuously pumped, Q-switched, solid-state or gas laser, through control of the optical power delivered by an optical pump to the laser, in order to limit the energy emitted in any single laser pulse as a result of Q-switching. The laser pump is driven at full strength for a selected initial refresh time t. sub. r. If a Q-switch trigger signal is received by the laser before the elapsed time. DELTA. t has reached the refresh time t. sub. r, the laser emits a pulse with the reduced energy stored in the laser at that time. If the elapsed time reaches or exceeds the refresh time t. sub. r, the optical pump power subsequently delivered to the laser is reduced to a lower level, which may be time-dependent, that is sufficient to maintain the net energy stored in the laser at a predetermined value so that the energy in a subsequently emitted laser pulse does not exceed a selected limit. Numerous techniques for controlling the optical pump power delivered are disclosed.