Long-pulse-width variable-wavelength chirped pulse generator and method

• US 10,408,676 B2
• Filed: 10/03/2016
• Issued: 09/10/2019
• Est. Priority Date: 10/01/2015
• Status: Active Grant

• Current Assignee: National Security Technologies LLC
• Original Assignee: Mission Support And Test Services, LLC (Jacobs Solutions, Inc.)
• Inventors: Capelle, Gene A., Frayer, Daniel K.
• Primary Examiner(s): Tumebo, Tsion
• Application Number:
  US15/284,399
• Publication Number:
  US 20170122806A1
• Time in Patent Office: 1,072 Days
• Field of Search: 36221714
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/08086 Multiple-wavelength emission
• CPC Class Codes: H01S 3/094034 the pumped medium being a dye
• CPC Class Codes: H01S 3/094076 Pulsed or modulated pumping H01S3/1024 takes precedence
• CPC Class Codes: H01S 3/213 including an organic dye

Abstract

A device for creating an optic pulse with different wavelengths separated by time. A pump laser is configured to output energy to a dye cell which, responsive to the energy, outputs an optic pulse. Mirrors direct the optic pulse away from the dye cell towards a spectrograph. The spectrograph has an input and two or more outputs. The spectrograph receives and converts the optic pulse to a wavelength separated optic signal presented on the two or more outputs. A first optic cable has an input end and an output end. The input end receives a first output from the spectrograph. A second optic cable has an input end and an output end. The input end receives a second output from the spectrograph. The second optic cable is a different length than the first optic cable to establish a time shift between the signals exiting the first and second cable.

Claims

1. A device for creating an optic pulse with different wavelengths separated by time comprising:

a pump laser configured to output an energy pulse;

a dye cell configured to receive the energy pulse from the pump laser and output a wideband optic pulse comprising a range of wavelengths;

one or more mirrors configured to direct the wideband optic pulse away from the dye cell;

a spectrograph having an input and two or more outputs, the spectrograph configured to receive the wideband optic pulse from the dye cell after reflection by the one or more mirrors on the input and convert the optic pulse to a wavelength separated optic signal that are presented on the two or more outputs;

a first optic cable having an input end and an output end, the input end configured to receive a first output from the spectrograph;

a second optic cable having an input end and an output end, the input end configured to receive a second output from the spectrograph, the second optic cable having a different length than the first optic cable;

a coupler configured to combine the light signal from the output end of the first optic cable and the second optic cable to a single path; and

an iris configured to receive the combined light signal and illuminate a scene of interest with the combined light source.

2. The device of claim 1 further comprising:

one or more lenses configured to focus the energy from the pump laser to the dye cell; and

one or more lenses configured to focus the output of the dye cell to the spectrograph.

3. The device of claim 1, wherein the second optic cable is 1.5 meters or more longer than the first optic cable.

4. The device of claim 1 further comprising additional optic cables having an input end and an output end, the input end configured to receive an additional output from the spectrograph, the additional optic cables having a different length than the first optic cable and the second optic cable.

5. The device of claim 1 wherein the output end of the first optic cable and the output end of the second optic cable are contained in one or more SMA connectors.

6. The device of claim 1 wherein the coupler is a large core fiber arranged to accept the first output from the first optic cable and second output from the second optic cable.

7. The device of claim 1 wherein the energy from the pump laser is a 10 ns pulse width at 532 nm wavelength.

8. The device of claim 6 further comprising a fiber core size larger than a slit width of the spectrograph.

9. A device for creating a chirped optic pulse defined as an optic pulse with different wavelengths separated by time comprising:

a pulse generator configured to output an optic pulse, the optic pulse comprising a multiple wavelength pulse;

a wavelength dispersive device having an input and two or more outputs, the wavelength dispersive device configured receive the optic pulse on the input and convert the optic pulse to at least one wavelength separated optic signal that is presented on the two or more outputs;

a first optic cable having a first optic cable input and a first optic cable output, the first optic cable input configured to receive a first output from the wavelength dispersive device and present a first optic cable output signal from the first optic cable output;

a second optic cable having an second optic cable input and a second optic cable output, the second optic cable input configured to receive a second output from the wavelength dispersive device and present a second optic cable output signal from the first optic cable output, the second optic cable having a different length than the first optic cable, thereby causing a time shift in the second optic cable output signal as compared to the first optic cable output signal;

a fiber core configured to combine the first optic cable output signal and the second optic cable output signal onto a single core to create a combined light signal; and

an iris configured to receive the combined light signal and illuminate a scene of interest with the combined light source.

10. The device of claim 9 further comprising one or more lenses configured to focus the energy from the pump laser and one or more lenses configured to focus the output of the dye cell.

11. The device of claim 9 wherein the second optic cable is 1.5 meters or more longer than the second optic cable.

12. The device of claim 9 wherein the energy from the pump laser is a 10 ns pulse width at 532 nm wavelength.

13. The device of claim 9 further comprising a fiber core size larger than a slit width of the spectrograph.

14. The device of claim 9 wherein the wavelength dispersive device is a spectrograph and the pulse generator generates a multiband pulse.

15. A method for generating a chirped optic pulse comprising:

generating laser pulse, the laser pulse including two or more wavelengths;

receiving the laser pulse at a wavelength dispersive device, the wavelength dispersive device spreading the laser pulse into at least a first output having a first wavelength and a second output having a second wavelength;

receiving the first optic output on a first optic path;

receiving the second optic output on a second optic path, the second optic path having a different length than the first optic path; and

outputting a first path output from the first optic path and a second path output from the second optic path to a coupler configured to combine the first path output and the second path output to create a combined light signal; and

providing the combined light signal to an iris configured to receive the combined light signal and illuminate a scene of interest with the combined light source.

16. The method of claim 15 wherein the generating a laser pulse comprises providing exciting energy to a dye cell and responsive to the exciting energy, the dye cell outputting the laser pulse.

17. The method of claim 15 further comprising combining the first path output and the second path output onto a single fiber.

18. The method of claim 15 wherein the wavelength dispersive device comprises a spectrograph.

19. The method of claim 15 wherein the first optic path and the second optic path comprise optic fibers.