TUNABLE RF FILTER DEVICE USING OPTICAL WAVEGUIDES WITH DISPERSION SLOPES OF OPPOSITE SIGNS AND RELATED METHODS

• US 20130028551A1
• Filed: 07/25/2011
• Published: 01/31/2013
• Est. Priority Date: 07/25/2011
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: DeSALVO, Richard, Middleton, Charles
• Granted Patent: US 8,897,607 B2
• Time in Patent Office: Days
• US Class Current: 385/2
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/025 in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 1/035 in an optical waveguide structure
• CPC Class Codes: H03H 2/003 comprising optical fibre network elements optical elements per se G02B, G02F; transmission systems using light waves H04B10/00
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
• 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 tunable Radio Frequency (RF) filter device includes a tunable optical source configured to generate an optical carrier signal, and a modulator coupled to the tunable optical source and configured to modulate the optical carrier signal with an RF input signal. The tunable RF filter device may also include first and second optical waveguides coupled to the modulator and having first and second dispersion slopes of opposite sign, and an optical-to-electrical converter coupled to the first and second optical waveguides and configured to generate an RF output signal with a frequency notch therein based upon the tunable optical source.

Claims

1. A tunable Radio Frequency (RF) filter device comprising:

a tunable optical source configured to generate an optical carrier signal;

a modulator coupled to said tunable optical source and configured to modulate the optical carrier signal with an RF input signal;

first and second optical waveguides coupled to said modulator and having first and second dispersion slopes of opposite sign; and

an optical-to-electrical converter coupled to said first and second optical waveguides and configured to generate an RF output signal with at least one frequency notch therein based upon said tunable optical source.

2. The tunable RF filter device of claim 1 further comprising a controller coupled to said tunable optical source and configured to tune a frequency of the optical carrier signal over a desired frequency range.

3. The tunable RF filter device of claim 2 wherein said controller is configured to tune the frequency of the optical carrier signal to generate the RF output signal with the at least one frequency notch therein by causing interference between outputs of said first and second optical waveguides.

4. The tunable RF filter device of claim 2 wherein the first and second dispersion slopes intersect at a desired frequency point in the desired frequency range.

5. The tunable RF filter device of claim 1 wherein said optical-to-electrical converter comprises:

first and second optical detectors coupled respectively to said first and second optical waveguides; and

a combiner coupled to said first and second optical detectors.

6. The tunable RF filter device of claim 1 wherein said first and second optical waveguides comprise first and second optical fibers.

7. The tunable RF filter device of claim 1 wherein said tunable optical source comprises a tunable continuous wave laser.

8. The tunable RF filter device of claim 1 further comprising an antenna coupled to said modulator and configured to provide the RF input signal.

9. The tunable RF filter device of claim 1 wherein said modulator comprises a dual-output Mach-Zehnder modulator.

10. A tunable Radio Frequency (RF) filter device comprising:

a tunable optical source configured to generate an optical carrier signal;

a controller coupled to said tunable optical source and configured to tune a frequency of the optical carrier signal over a desired frequency range;

a modulator coupled to said tunable optical source and configured to modulate the optical carrier signal with an RF input signal;

first and second optical waveguides coupled to said modulator and having first and second dispersion slopes of opposite sign; and

an optical-to-electrical converter configured to generate an RF output signal with at least one frequency notch therein based upon said tunable optical source and comprising first and second optical detectors coupled respectively to said first and second optical waveguides, and a combiner coupled to said first and second optical detectors.

11. The tunable RF filter device of claim 10 wherein said controller is configured to tune the frequency of the optical carrier signal to generate the RF output signal with the at least one frequency notch therein by causing interference between outputs of said first and second optical waveguides.

12. The tunable RF filter device of claim 10 wherein the first and second dispersion slopes intersect at a desired frequency point in the desired frequency range.

13. The tunable RF filter device of claim 10 wherein said first and second optical waveguides comprise first and second optical fibers.

14. The tunable RF filter device of claim 10 wherein said tunable optical source comprises a tunable continuous wave laser.

15. The tunable RF filter device of claim 10 further comprising an antenna coupled to said modulator and configured to provide the RF input signal.

16. A method of Radio Frequency (RF) filtering comprising:

generating an optical carrier signal using a tunable optical source;

modulating the optical carrier signal with an RF input signal using a modulator coupled to the tunable optical source and first and second optical waveguides coupled to the modulator and having first and second dispersion slopes of opposite sign; and

generating an RF output signal with at least one frequency notch therein based upon the tunable optical source using an optical-to-electrical converter coupled to the first and second optical waveguides.

17. The method of claim 16 further comprising tuning a frequency of the optical carrier signal over a desired frequency range.

18. The method of claim 17 further comprising tuning the frequency of the optical carrier signal to generate the RF output signal with the at least one frequency notch therein by causing interference between outputs of the first and second optical waveguides.

19. The method of claim 17 wherein the first and second dispersion slopes intersect at a desired frequency point in the desired frequency range.

20. The method of claim 16 further comprising generating the optical carrier signal using a tunable continuous wave laser.

21. The method of claim 16 further comprising receiving the RF input signal with an antenna coupled to the modulator.