HIGH PERFORMANCE COMPACT RF RECEIVER FOR SPACE FLIGHT APPLICATIONS

• US 20150132005A1
• Filed: 11/14/2013
• Published: 05/14/2015
• Est. Priority Date: 11/14/2013
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Karras, Thomas W., Paolella, Arthur, Robertson, Stephen V., Sroga, Jeffrey T.
• Granted Patent: US 9,413,471 B2
• Time in Patent Office: Days
• US Class Current: 398/115
• CPC Class Codes: H04B 10/90 Non-optical transmission systems, e.g. transmission systems employing non-photonic corpuscular radiation
• CPC Class Codes: H04B 2210/006 Devices for generating or processing an RF signal by optical means

Abstract

A compact photonic radio frequency receiver system includes a laser source that is configured to generate laser light Radio frequency (RF) and local oscillator (LO) input ports may receive RF and LO signals, respectively. One or more miniature lithium niobate waveguide phase modulators may be coupled to the laser source to receive the RF and LO signals and to modulate the laser light with the RF and LO signals in a first and a second path, and to generate phase-modulated laser lights including an RF-modulated light signal and an LO-modulated light signal. A first and a second miniature filter may be coupled to the miniature lithium niobate waveguide to separate a desired spectral band in the phase-modulated laser light of the first path and to facilitate wavelength locking of the laser light of the second path. An optical combiner may combine output laser lights of the first and second filters

Claims

1. A compact photonic radio frequency receiver system for space and airborne applications, the system comprising:

a laser source configured to generate laser light;

radio frequency (RF) and local oscillator (LO) input ports configured to receive RF and LO signals, respectively;

one or more centimeter scale or smaller waveguide phase modulators coupled to the laser source and configured to receive the RF and LO signals and to modulate the laser light with the RF and LO signals in a first and a second path and to generate phase-modulated laser lights including an RF-modulated light signal and an LO-modulated light signal; and

a first and a second centimeter scale or smaller filters coupled to the centimeter scale or smaller waveguide phase modulators, the first centimeter scale or smaller filter configured to separate a desired spectral band in the phase-modulated laser light of the first path and the second centimeter scale or smaller filter configured to pass a first portion of the LO-modulated light signal for heterodyne purposes and to reflect a second portion of the LO modulated signal to facilitate wavelength locking of the laser light of the second path; and

an optical combiner configured to combine output laser lights of the first and second filters.

2. The system of claim 1, further comprising a millimeter scale optical switch array coupled to the optical combiner and configured to switch multiple channels of the modulated and filtered laser lights from one or more receivers to one or more destinations including one or more detectors.

3. The system of claim 2, further comprising a millimeter scale balanced detector coupled to the optical switch array and configured to perform a heterodyne process by down converting the RF-modulated and filtered light signal using the LO-modulated and filtered light signal and to recover a radio frequency output with a desired downlink frequency component.

4. The system of claim 1, wherein the laser source comprises a millimeter scale semiconductor distributed feedback laser, and wherein the phased-modulated laser lights comprise an uplink frequency component, a data component, and an LO component

5. The system of claim 1, wherein the first centimeter scale or smaller filter comprises a millimeter scale optical RF multi-pole filter and is configured to separate a desired spectral band in the phase-modulated laser light of the first path by filtering a desired downlink frequency component from all other components of the phase-modulated laser lights.

6. The system of claim 5, wherein the optical RF multi-pole filter comprises a monolithic assembly of millimeter scale multiple free standing whispering gallery mode resonators.

7. The system of claim 5, wherein the optical RF multi-pole filter comprises an assembly of photo-lithographically formed resonators on a single chip or multiple chips.

8. The system of claim 5, wherein the optical RF multi-pole filter comprises one of an assembly of Fabry-Pé

rot filters or a fiber Bragg grating filter configured so as to fit in a volume of 1 cm scale.

9. The system of claim 1, wherein the second centimeter scale or smaller filter comprises a millimeter to centimeter scale optical LO filter and is configured to separate a desired spectral band in the phase-modulated laser light of the second path by filtering a desired wavelength component from other components of the phase-modulated laser lights, wherein the optical LO filter comprises one of a single-pole or notch filter, and wherein the desired wavelength component comprises at least one of a primary carrier wavelength or a corresponding LO side-band.

10. The system of claim 9, wherein the optical LO filter comprises a monolithic assembly of millimeter scale free standing whispering gallery mode resonators.

11. The system of claim 9, wherein the optical LO filter comprises one of an assembly of photo-lithographically formed resonators on a single chip or multiple chips, an assembly of Fabry-Pé

rot filters, or a fiber Bragg grating filter configured to fit in a volume of 1 cm scale.

12. The system of claim 1, wherein each of the centimeter scale or smaller waveguide phase modulators comprises a lithium niobate waveguide phase modulator.

13. The system of claim 1, wherein the optical switch array comprises one of silicon waveguide-based or lithium niobate Mach Zehnder Interferometers or silicon based photonic crystals.

14. The system of claim 1, wherein each centimeter scale or smaller waveguide phase modulator comprises smaller than two cm lithium niobate waveguide phase modulators and is operable at frequencies up to and beyond 100 GHz.

15. The system of claim 14, wherein each centimeter or smaller scale waveguide phase modulator is formed with silicon, indium phosphide or other semiconductor waveguides and is operable at frequencies up to and beyond 100 GHz.

16. The system of claim 15, wherein each centimeter scale or smaller waveguide phase modulator is operable at frequencies up to and beyond 100 GHz.

17. The system of claim 15, wherein the centimeter or smaller scale waveguide phase modulator comprises a low loss modulator with a watt level or greater optical power handling capability.

18. The system of claim 1, further comprising free space micro-optics configured to transport optical signals between at least some of the laser source, the centimeter or smaller scale waveguide phase modulator, an optical RF multi-pole filter, an optical switch array, and a detector, and wherein the free space micro-optics further comprise millimeter scale optics.

19. The system of claim 1, further comprising high contrast gratings configured to transport optical signals between at least some of the laser source, the centimeter or smaller scale waveguide phase modulator, an optical RF multi-pole filter, an optical switch array, and a detector.

20. The system of claim 1, further comprising polymer based self-forming waveguides configured to transport optical signals between at least two of the laser source, the centimeter or smaller scale waveguide phase modulator, an optical RF multi-pole filter, an optical switch array, and a detector.

21. The system of claim 1, further comprising fiber-based waveguides configured to transport optical signals between at least two of the laser source, the cm or smaller scale waveguide phase modulator, an optical RF multi-pole filter, an optical switch array, and a detector.

22. A method of using photonics in a space borne or airborne radio frequency (RF) communication or electronic warfare (EW) system, comprising:

using one or more centimeter or smaller scale lithium niobate waveguide phase modulators to phase-modulate an RF signal including a data component received from an uplink source to an optical carrier to generate an RF-modulated light signal;

using the one centimeter or smaller scale lithium niobate waveguide modulators to phase-modulate a local oscillator (LO) signal to the optical carrier to generate an LO-modulated light signal;

filtering using, millimeter to centimeter scale optical filters, the RF-modulated and the LO-modulated light signals; and

processing the RF-modulated light signal and the LO-modulated light signal to recover a downlink frequency component and generating a downlink signal including the data component.

23. The method of claim 22, further comprising combining and switching filtered RF-modulated and the LO-modulated light signal.

24. The method of claim 22, further comprising using free space micro-optics to transport the optical carrier between at least some modules of a plurality of modules including the one or more lithium niobate waveguide phase modulators and modules that perform the steps of filtering and processing, and wherein the free space micro-optics comprise millimeter scale optics.

25. The method of claim 22, further using high contrast gratings to transport the optical carrier between at least two modules of a plurality of modules including the lithium niobate waveguide phase modulator and modules that perform the steps of, filtering, and processing.

26. The method of claim 22, further comprising using optical fibers to transport the optical carrier between at least two modules of a plurality of modules including the lithium niobate waveguide phase modulator and modules that perform the steps of filtering, and processing.

27. A compact photonic radio frequency receiver system for space flight applications, the system comprising:

a laser source chip configured to generate a carrier laser light;

one or more miniature lithium niobate waveguide phase modulators coupled to the laser source and configured to modulate the carrier laser light with an RF and a local oscillator (LO) signal and to generate phase-modulated laser lights; and

miniature optical filters coupled to the one or more miniature lithium niobate waveguides and configured to separate a desired spectral band in the phase-modulated laser lights and to facilitate wavelength locking of the carrier laser light, the miniature filters comprising an optical RF multi-pole filter;

a miniature optical switch array coupled to the miniature optical filters and configured to switch multiple channels of modulated and filtered laser lights; and

a miniature detector coupled to the optical switch array and configured to perform a heterodyne process by mixing the RF-modulated light signal and the LO-modulated light signal and to recover a radio frequency output of a desired downlink frequency component.