Integrated photonics device for continuous phase-controlled active beam steering and forming

• US 10,534,110 B2
• Filed: 01/09/2018
• Issued: 01/14/2020
• Est. Priority Date: 01/09/2018
• Status: Active Grant

• Current Assignee: Precision Optical Technologies Incorporated
• Original Assignee: Precision Optical Transceivers Inc.
• Inventors: Tennant, Bryce, Adams, Donald
• Primary Examiner(s): Phan, Hanh
• Application Number:
  US15/865,779
• Publication Number:
  US 20190212472A1
• Time in Patent Office: 735 Days
• Field of Search: 398115, 398116, 398117, 398141, 398158, 398159, 398162, 398188, 398135, 398136, 398137, 398138, 398139, 398201, 398187, 398186, 398 66, 398 68, 398 72, 342375, 342368, 342373, 342372, 342374
• CPC Class Codes: G02B 1/005 made of photonic crystals or photonic band gap materials photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295
• CPC Class Codes: G02B 5/28 Interference filters
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/3526 the optical element being a lens
• CPC Class Codes: G02B 6/354 Switching arrangements, i.e. number of input/output ports and interconnection types
• CPC Class Codes: G02F 1/3136 of interferometric switch type
• CPC Class Codes: H01Q 3/2676 Optically controlled phased array
• CPC Class Codes: H01Q 5/22 RF wavebands combined with non-RF wavebands, e.g. infrared or optical
• CPC Class Codes: H04B 10/25752 Optical arrangements for wireless networks
• CPC Class Codes: H04B 10/50 Transmitters
• CPC Class Codes: H04Q 11/0003 Details

Abstract

An RF transmit signal is modulated onto an optical carrier to form a transmit modulated optical carrier (TMOC). The TMOC is split into N transmit modulated optical subcarriers (TMOS). Each TMOS is respectively processed in one of N transmit optical channels (TOCs). In each TOC, RF antenna beam steering operations are performed by optical tuning the TMOS to selectively control a phase difference between the optical carrier and the optical sideband. A different selected phase difference can be applied in each TOC. The TMOS from each of the N TOCs is then processed to obtain N RF signals for driving an antenna array. In the receive direction, M received RF signals from M antenna elements are modulated respectively onto M optical subcarriers to form M receive modulated optical subcarriers (RMOS). RF antenna beam steering operations are performed by optical tuning the RMOS.

Claims

1. A method for controlling a phased array antenna system, comprising:

modulating an RF transmit signal onto an optical carrier to form a transmit modulated optical carrier (TMOC) comprised of the optical carrier and an optical sideband;

splitting the TMOC into N transmit modulated optical subcarriers (TMOS), where N is an integer value greater than 1;

respectively processing each TMOS in one of N transmit optical channels (TOCs);

in each TOC, performing RF antenna beam steering operations by optical tuning the TMOS to selectively control a phase difference between the optical carrier and the optical sideband;

processing the TMOS from each of the N TOCs to obtain N RF signals, each having a controlled phase attribute as a result of the optical tuning; and

communicating the N RF signals respectively to N antenna elements which comprise an antenna array;

wherein a phase adjustment that is applied to each TMOS is selectively coordinated so as to control a boresight direction of a composite antenna transmit beam produced by the N antenna elements when excited by the N RF signals.

2. The method according to claim 1, further comprising in each TOC, performing RF antenna beam forming operations by optically tuning the TMOS to selectively control an amplitude of the RF signal applied to each of the N antenna elements.

3. The method according to claim 2, further comprising receiving in each of the N TOCs a channel amplitude control signal applicable to a respective one of the N transmit optical channels and specifying an amplitude adjustment to be applied using the optical tuning.

4. The method according to claim 1, wherein the phase difference between the optical carrier and the optical sideband of each said TMOS is controlled in the TOC using a phase control ring.

5. The method according to claim 4, wherein the phase difference between the optical carrier and the optical sideband of each said TMOS is controlled in the TOC using a switchable delay element.

6. The method according to claim 1, further comprising:

modulating M received RF signals from M antenna elements respectively onto M optical subcarriers to form M receive modulated optical subcarriers (RMOS), each comprised of a receive optical subcarrier signal and a receive optical sideband signal, where M is an integer value greater than 1;

processing one of the RMOS respectively in each of M receive optical channels (ROCs); and

in each ROC, performing RF antenna beam steering operations by optical tuning the RMOS to selectively control a phase difference as between the receive optical carrier signal and the receive optical sideband signal.

7. The method according to claim 6, further comprising adjusting a phase of the receive optical carrier signal in each of the M ROCs so as to match a phase of the receive optical carrier signal in each other of the M ROC.

8. The method according to claim 7 further comprising optically combining the M RMOS to form a receive modulated optical carrier (RMOC).

9. The method according to claim 8, further comprising communicating the RMOC to a photodetector to extract a combined receive RF signal.

10. The method according to claim 6, further comprising selectively coordinating the phase difference that is applied in each of the M RMOS so as to control a boresight direction of a composite antenna receive beam produced by the N antenna elements.

11. A method for controlling a phased array antenna system, comprising:

modulating an RF transmit signal onto an optical carrier to form a transmit modulated optical carrier (TMOC) comprised of the optical carrier and an optical sideband;

splitting the TMOC into N transmit modulated optical subcarriers (TMOS), where N is an integer value greater than 1;

respectively processing each TMOS in one of N transmit optical channels (TOCs);

in each TOC, performing RF antenna beam steering operations by optical tuning the TMOS to selectively control a phase difference between the optical carrier and the optical sideband;

receiving in each TOC a channel phase control signal applicable to a respective one of the TMOS, the phase control signal determining a phase adjustment to be applied to the TMOS using the optical tuning;

processing the TMOS from each of the N TOCs to obtain N RF signals, each having a controlled phase attribute as a result of the optical tuning; and

communicating the N RF signals respectively to N antenna elements which comprise an antenna array.

12. A beam steering system, comprising:

a control processor;

a transmit path module (TPM) configured for receiving as an input a transmit modulated optical carrier (TMOC) comprised of an optical carrier and an RF modulated optical sideband;

an optical splitter in which the TMOC is split into N transmit modulated optical subcarriers (TMOS), where N is an integer value greater than 1; and

a plurality of N transmit optical channels (TOCs), each respectively comprising

a plurality of optical tuning elements configured optical tuning one of the N TMOS to selectively control a phase difference between the optical carrier and the RF modulated optical sideband comprising the TMOS; and

a photodetector configured to extract from the TMOS an RF subcarrier signal in which the signal phase has been selectively modified by the optical tuning;

wherein the control processor is configured to selectively independently control the phase difference applied to the TMOS in each of the N TOCs to coordinate antenna beam steering when a plurality of the RF subcarrier signals are communicated to antenna elements comprising an antenna array.

13. The beam steering system according to claim 12, wherein the phase difference between the optical carrier and the optical sideband of each said TMOS is controlled in the TOC using a phase control ring.

14. The beam steering system according to claim 13, wherein the phase difference between the optical carrier and the optical sideband of each said TMOS is controlled in the TOC using a switchable delay element.

15. The beam steering system according to claim 13, further comprising

a receive path module (RPM) comprised of M receive optical channels (ROCs), each ROC configured for receiving as an input a receive RF signal from a corresponding one of M receive antenna element of an antenna array, and where M is an integer greater than 1;

wherein each ROC is comprised of

an optical modulator configured for modulating the receive RF signal onto a receive optical carrier to form a receive modulated optical subcarrier (RMOS) comprised of an optical carrier and an RF modulated optical sideband;

a plurality of optical tuning elements configured to optical tune the RMOS so as to selectively control a phase difference between the optical carrier and the RF modulated optical sideband comprising the RMOS; and

a phase matching element configured to facilitate a phase match of the optical carrier of the RMOS to each other of the M RMOS.

16. The beam steering system according to claim 15, wherein the RPM is further comprised of an optical combiner coupled to each ROC and configured to combine the M RMOS and thereby produce a single receive modulated optical carrier (RMOC) as an output.

17. The beam steering system according to claim 16, further comprising a photodetector configured to extract from the RMOC an RF signal.

18. The beam steering system according to claim 16, wherein the control processor is further configured to selectively independently control the phase difference applied in each of the M ROC to coordinate receive beam antenna steering.

19. The beam steering system according to claim 12, wherein at least one of the plurality of optical tuning elements is configured to selectively control an amplitude of the TMOS;

and

wherein the control processor is further configured to selectively independently control the amplitude of each TMOS to coordinate antenna beam forming.

20. A method for controlling a phased array antenna system, comprising:

modulating M received RF signals from M antenna elements respectively onto M optical subcarriers to form M receive modulated optical subcarriers (RMOS), each comprised of a receive optical subcarrier signal and at least one receive optical sideband signal, where M is an integer value greater than 1;

processing one of the RMOS respectively in each of M receive optical channels (ROCs);

in each ROC, performing RF antenna beam steering operations by optical tuning the RMOS to selectively control a phase difference as between the receive optical subcarrier signal and the receive optical sideband signal; and

controlling a phase of the receive optical subcarrier signal in each of the M ROCs so as to match a phase of the receive optical subcarrier signal in each other of the M ROC.

21. The method according to claim 20, further comprising optically combining the M RMOS after matching the phases of the M RMOS so as to form a receive modulated optical carrier (RMOC).

22. The method according to claim 21, further comprising communicating the RMOC to a photodetector to extract a combined receive RF signal.

23. The method according to claim 22, further comprising performing RF antenna beam forming operations in each ROC by optically tuning the RMOS to selectively control an amplitude of the RMOS.

24. A method for controlling a phased array antenna system, comprising:

modulating M received RF signals from M antenna elements respectively onto M optical subcarriers to form M receive modulated optical subcarriers (RMOS), each comprised of a receive optical subcarrier signal and at least one receive optical sideband signal, where M is an integer value greater than 1;

processing one of the RMOS respectively in each of M receive optical channels (ROCs);

in each ROC, performing RF antenna beam steering operations by optical tuning the RMOS to selectively control a phase difference as between the receive optical subcarrier signal and the receive optical sideband signal;

receiving in each ROC a channel phase control signal applicable to a respective one of the RMOS, the phase control signal specifying a phase difference adjustment to be applied to the RMOS using the optical tuning; and

optically combining the M RMOS after matching the phases of the M RMOS so as to form a receive modulated optical carrier (RMOC).

25. The method according to claim 24, further comprising selectively coordinating the phase difference that is applied to each of the M RMOS so as to control a boresight direction of a composite antenna receive beam produced by the M antenna elements.