Michael A Krainak

US Patent:

8547531, Oct 1, 2013

Filed:

Sep 1, 2010

Appl. No.:

12/873373

Inventors:

Michael A. Krainak - Fulton MD, US

Assignee:

The United States of America as represented by the Administrator of the National Aeronautics Space Administration - Washington DC

International Classification:

G01C 3/08

US Classification:

356 401, 356 301, 356 41, 356 501, 356 51

Abstract:

Disclosed is an apparatus and method for imaging a target area. Light is emitted from a device and separated into individual rays of light. These rays are then directed to a target area where they are reflected and returned to a receiving device. The time of flight for the individual rays of light is calculated to determine the range and shape of objects in the target area.

US Patent:

61887056, Feb 13, 2001

Filed:

May 15, 1998

Appl. No.:

9/079383

Inventors:

Michael A. Krainak - Eldersburg MD
Gary L. Duerksen - Lanham MD

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

H01S 5068
H01S 5065

US Classification:

372 32

Abstract:

Fiber Bragg grating coupled light sources can achieve tunable single-frequency (single axial and lateral spatial mode) operation by correcting for a quadratic phase variation in the lateral dimension using an aperture stop. The output of a quasi-monochromatic light source such as a Fabry Perot laser diode is astigmatic. As a consequence of the astigmatism, coupling geometries that accommodate the transverse numerical aperture of the laser are defocused in the lateral dimension, even for apsherical optics. The mismatch produces the quadratic phase variation in the feedback along the lateral axis at the facet of the laser that excites lateral modes of higher order than the TM. sub. 00. Because the instability entails excitation of higher order lateral submodes, single frequency operation also is accomplished by using fiber Bragg gratings whose bandwidth is narrower than the submode spacing. This technique is particularly pertinent to the use of lensed fiber gratings in lieu of discrete coupling optics.

US Patent:

20210306072, Sep 30, 2021

Filed:

Mar 11, 2021

Appl. No.:

17/199316

Inventors:

- Greebelt MD, US
Michael Krainak - Fulton MD, US

International Classification:

H04B 10/112
H04B 10/50

Abstract:

A method, system, and apparatus are disclosed for a free-space communication optical terminal comprising an optical telescope (or telescopes) for bidirectional communication and navigation, a pointing and tracking system for transmission and reception of narrow optical beams, and a modem.

US Patent:

20180058935, Mar 1, 2018

Filed:

Aug 25, 2016

Appl. No.:

15/246870

Inventors:

- Washington DC, US
MICHAEL A. KRAINAK - Fulton MD, US
Diego Janches - Tracys Landing MD, US
Sarah L. Jones - Bowie MD, US
Branimir Blagojevic - Ellicott City MD, US

International Classification:

G01J 5/10
H01S 3/0941
H01S 3/16
H01S 3/30
H01S 3/08
H01S 3/06
H01S 3/117
H01S 3/04
H01S 3/13
H01S 3/00
G01N 21/39
G01S 17/88

Abstract:

The present invention relates an apparatus and method for measuring range-resolved atmospheric sodium temperature profiles using a space-based Lidar instrument, including a diode-pumped Q-switched self-Raman c-cut Nd:YVOlaser with intra-cavity frequency doubling that could produce multi-watt 589 nm wavelength output. The c-cut Nd:YVOlaser has a fundamental wavelength that is tunable from 1063-1067 nm. A continuous wave narrow linewidth diode laser is used as an injection seeder to provide single-frequency grating tunable output around 1066 nm. The injection-seeded self-Raman shifted Nd:VOlaser is tuned across the sodium vapor Dline at 589 nm. In one embodiment, a space-qualified frequency-doubled 9 Watt at 532 nm wavelength Nd:YVOlaser, is utilized with a tandem interference filter temperature-stabilized fused-silica-etalon receiver and high-bandwidth photon-counting detectors.

US Patent:

20170082491, Mar 23, 2017

Filed:

Jun 23, 2016

Appl. No.:

15/190727

Inventors:

- Washington DC, US
MOLLY E. FAHEY - WASHINGTON DC, US
MICHAEL A. KRAINAK - FULTON MD, US

International Classification:

G01J 3/45
G02B 5/28
G01J 3/26
G02B 5/122

Abstract:

Systems, methods, and devices may provide an optical scheme that achieves simultaneous wavelength channels and maintains the resolution and luminosity of an etalon. Various embodiments may provide a method to optically recirculate the light reflected from the etalon back through the same etalon at new angles. Various embodiments create an etalon spectrometer based on angular dispersion without moving parts and without losing the light that is not initially transmitted. Various embodiments may provide a spectrally-resolved receiver and/or transmitter. Various embodiments may provide a system including a retro-reflector, a detector or transmitter array, and an etalon disposed between the retro-reflector and the detector or transmitter array, wherein the retro-reflector is configured to redirect light reflected by the etalon back to the etalon at a different angle of incidence than an original angle of incidence on the etalon of the light reflected by the etalon.