Optical signal processing systems and methods for amplification and/or attenuation

• US 8,103,175 B1
• Filed: 07/17/2008
• Issued: 01/24/2012
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Kowalczyk, Anthony C., Enoch, Michael
• Primary Examiner(s): CURS, NATHAN M
• Application Number:
  US12/175,411
• Time in Patent Office: 1,286 Days
• Field of Search: 398/85, 398/115, 398/200, 359/334
• US Class Current: 398/200
• CPC Class Codes: H04B 10/25759 Details of the reception of RF signal or the optical conversion before the optical fibre
• CPC Class Codes: H04B 2210/006 Devices for generating or processing an RF signal by optical means

Abstract

An optical signal processing system is provided that includes a first light modulator for receiving, placing information on a first optical signal, and for producing a second optical signal. The second optical signal includes a desired signal portion and an undesired signal portion. The optical signal processing system includes a second light modulator that tunes a first optical pump signal to a Brillouin frequency that is less than, but corresponding to, a frequency of the undesired signal portion. The optical signal processing system includes a light conductor configured to receive as a first input the second optical signal and as a second input the first optical pump signal tuned to the Brillouin frequency. The optical signal processing system causes the first optical pump signal tuned to the Brillouin frequency to induce a Stimulated Brillouin Scattering effect at the light conductor to attenuate the undesired signal portion.

Claims

1. An optical signal processing system, comprising:

a first light modulator configured to receive a first optical signal, the first light modulator configured to place information on the first optical signal, and the first light modulator configured to produce, from at least the first optical signal and the information, a second optical signal comprising a first signal portion that is desired (a “

desired signal portion”

) and a second signal portion that is not desired (an “

undesired signal portion”

);

a second light modulator configured to tune a first optical pump signal to a Brillouin frequency that is less than, but corresponding to, a frequency of the undesired signal portion;

a light conductor configured to receive as a first input the second optical signal and as a second input the first optical pump signal tuned to the Brillouin frequency, wherein the optical signal processing system is configured to cause the first optical pump signal tuned to the Brillouin frequency to induce a Stimulated Brillouin Scattering effect at the light conductor and is configured to attenuate the undesired signal portion;

a splitter configured to receive the first optical signal and to send the first optical signal to the first light modulator and to the second light modulator;

an isolator configured to receive the second optical signal, to send the second optical signal to the light conductor, and to isolate the light conductor from the first light modulator;

a first radio frequency generator configured to generate a first radio frequency signal; and

a first bias control unit configured to generate a first bias control signal, wherein the second light modulator is configured to receive the first radio frequency signal, the first bias control signal, and the first optical signal, and to produce the first optical pump signal.

2. The optical signal processing system of claim 1, further comprising:

a third light modulator configured to tune a second optical pump signal to a second Brillouin frequency that is more than, but corresponding to, a frequency of the desired signal portion,

wherein the light conductor is further configured to receive the second optical pump signal tuned to the second Brillouin frequency, and

wherein the optical signal processing system is configured to cause the second optical pump signal tuned to the second Brillouin frequency to induce a Stimulated Brillouin Scattering effect in the light conductor and is configured to amplify the desired signal portion.

3. The optical signal processing system of claim 1, wherein the information is derived from a second radio frequency signal.

4. The optical signal processing system of claim 1, wherein the light conductor is of a length between ½

of a kilometer and 30 kilometers.

5. The optical signal processing system of claim 1, further comprising:

a processor,

wherein the second light modulator is configured to selectively tune the first optical pump signal based on an input received from the processor.

6. The optical signal processing system of claim 2, further comprising:

a processor,

wherein the third light modulator is configured to selectively tune the second optical pump signal based on an input from the processor.

7. The optical signal processing system of claim 1, wherein a power level of the first optical pump signal is less than a Brillouin threshold power.

8. The optical signal processing system of claim 2, wherein a power level of the second optical pump signal is less than a Brillouin threshold power.

9. The optical signal processing system of claim 1, wherein the optical signal processing system is configured to attenuate the undesired signal portion within a frequency bandwidth of tens of MHz or less.

10. The optical signal processing system of claim 2, wherein the optical signal processing system is configured to amplify the desired signal portion within a frequency bandwidth of tens of MHz or less.

11. The optical signal processing system of claim 1, further comprising an antenna, wherein the first light modulator is configured to receive a radio frequency input from the antenna.

12. The optical signal processing system of claim 1, further comprising:

a first amplifier configured to receive the first optical pump signal from the second modulator and to amplify the first optical pump signal;

a circulator configured to receive the first optical pump signal from the first amplifier, to route the first optical pump signal to the light conductor, and to route an output of the light conductor to a detector; and

a detector configured to receive the output of the light conductor and to detect information in the output of the light conductor.

13. The optical signal processing system of claim 1, further comprising:

a second radio frequency generator configured to generate a second radio frequency;

a second bias control unit configured to generate a second bias control signal;

a third light modulator configured to receive the second radio frequency, the second bias control signal, and the first optical signal, and to create a second optical pump signal from the second radio frequency, the second bias control signal, and the first optical signal,

wherein the light conductor is configured to receive the second optical pump signal.

14. The optical signal processing system of claim 1, wherein the light conductor comprises an end and an opposing end, the end of the light conductor configured to receive the first input, and one of the end and the opposing end of the light conductor configured to receive the second input.

15. The optical system of claim 2, wherein the light conductor comprises an end and an opposing end, the end of the light conductor configured to receive the first input;

and the opposing end of the light conductor configured to receive the second input.

16. The optical signal processing system of claim 1, wherein

the second light modulator is configured to tune a second optical pump signal to a second Brillouin frequency that is more than, but corresponding to, a frequency of the desired signal portion,

the light conductor is configured to receive the second optical pump signal tuned to the second Brillouin frequency and the second optical signal, and

the optical signal processing system is configured to cause the second optical pump signal to induce a Stimulated Brillouin Scattering effect at the light conductor and is configured to amplify the desired signal portion.

17. An optical signal processing method, comprising:

sending, by a splitter, a first optical signal to a first light modulator and to a second light modulator;

modulating, by the first light modulator, the first optical signal with information to produce a second optical signal, the second optical signal comprising a first signal portion that is desired and a second signal portion that is not desired;

generating, by a first radio frequency generator, a first radio frequency signal;

generating, by a first bias control unit, a first bias control signal;

receiving, by the second light modulator, the first radio frequency signal, the first bias control signal, and the first optical signal;

producing, by the second light modulator, a first optical pump signal based on the first radio frequency signal, the first bias control signal, and the first optical signal;

tuning, by the second light modulator, the first optical pump signal to a Brillouin frequency that is less than, but corresponding to, a frequency of the second signal portion that is not desired;

isolating, by an isolator, a light conductor from the first light modulator;

receiving, at the light conductor, the second optical signal as a first input;

receiving, at the light conductor, the first optical pump signal as a second input;

inducing a Stimulated Brillouin Scattering effect in the light conductor utilizing the first optical pump signal; and

attenuating the second signal portion that is not desired.

18. The optical signal processing method of claim 17, further comprising:

tuning a second optical pump signal to a Brillouin frequency that is more than, but corresponding to, a frequency of the first signal portion that is desired;

receiving, at the light conductor, the second optical pump signal as a third input;

inducing a Stimulated Brillouin Scattering effect in the light conductor utilizing the second optical pump signal; and

amplifying the first signal portion that is desired.

19. The optical signal processing method of claim 17, further comprising:

receiving the first optical signal prior to the step of the modulating; and

receiving a second radio frequency signal comprising the information prior to the modulating,

wherein a power level of the first optical pump signal is less than a Brillouin threshold power.