Multi-beam optical phased array

Patent metadata

Field	Value
Publication number	US-10944477-B2
Application number	US-201916458911-A
Country	US
Kind code	B2
Filing date	Jul 1, 2019
Priority date	Jun 29, 2018
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

An optical phased array, includes, in part, K beam processors each adapted to receive a different one of K optical signals and generate N optical signals in response. The difference between the phases of optical signals a LM and a L(M+1) is the same for all Ms, where M is an integer ranging from 1 to N−1 defining the signals generated by a beam processor, and L is an integer ranging from 1 to K defining the beam processor generating the K optical signals. The transmitter further includes, in part, a combiner adapted to receive the N×K optical signals from the K beam processors and combine the K optical signals from different ones of the K beam processors to generate N optical signals. The transmitter further includes, in part, N radiating elements each adapted to transmit one of the N optical signals.

First claim

What is claimed is:

1. An optical phased array transmitter comprising:
K beam processors, each beam processor adapted to receive a different one of K optical signals and generate N optical signals in response wherein a difference between phases of optical signals a LM and a L(M+1) is the same for all Ms, where M is an integer ranging from 1 to N−1 defining the signals generated by a beam processor, and L is an integer ranging from 1 to K defining the beam processor generating K optical signals;
a combiner adapted to:
receive the N×K optical signals from the K beam processors; and
combine K optical signals from different ones of the K beam processors to generate N optical signals; and
N radiating elements each adapted to radiate one of the N optical signals.

2. The optical phased array transmitter of claim 1 wherein a difference between phases of each pair of associated optical signals generated by the same beam processor is a same.

3. The optical phased array transmitter of claim 2 further comprising:
a splitter adapted to generate the K optical signals from a received optical signal.

4. The optical phased array transmitter of claim 2 wherein each of the K optical signals has a different wavelength.

5. The optical phased array transmitter of claim 2 wherein each beam processor comprises:
a modulator adapted to modulate an amplitude and/or phase of the optical signal the beam processor receives.

6. The optical phased array transmitter of claim 5 wherein each beam processor further comprises:
a plurality of splitters adapted to split the modulated optical into N optical signals.

7. The optical phased array transmitter of claim 6 wherein each beam processor further comprises:
a plurality of phase shifters each adapted to shift a phase of one of the N optical signals.

8. The optical phased array transmitter of claim 6 wherein each beam processor further comprises:
a plurality of optical signal measurement units each adapted to receive and convert a portion of one of the N optical signals to an electrical signal.

9. The optical phased array transmitter of claim 8 wherein each optical signal measurement unit comprises a photo-detector adapted to generate an electrical signal in response to a voltage that is turned on and off during different time periods.

10. The optical phased array transmitter of claim 6 wherein each beam processor further comprises:
a plurality of optical signal measurement units each adapted to receive and combine a portion of a different pair of N optical signals and convert the combined signal to an electrical signal.

11. The optical phased array transmitter of claim 6 wherein each beam processor further comprises a plurality of optical signal measurement units each comprising:
a first optical signal coupler adapted to receive a portion of a first one of the N optical signals;
a first splitter adapted to split the portion of the first optical signal into third and fourth optical signals;
a second optical signal coupler adapted to receive a portion of a second one of the N optical signals;
a second optical splitter adapted to split the portion of the second optical signal into fifth and sixth optical signals;
a phase shifter adapted to shift the phase of the fifth optical signal by a first value to generate a seventh optical signal;
a first optical signal combiner adapted to combine the third and sixth optical signals to generate an eight optical signal;
a second optical signal combiner adapted to combine the fourth and seventh optical signals to generate a ninth optical signal;
a first photo-detector adapted to convert the eight optical signal into a first electrical signal; and
a second photo-detector adapted to convert the ninth optical signal into a second electrical signal.

12. The optical phased array transmitter of claim 11 wherein the first value is defined by 90°.

13. The optical phased array transmitter of claim 12 further comprising:
a processing unit configured to determine a phase of the first optical signal relative to the phase of the second optical signal from the first and second electrical signals.

14. The optical phased array transmitter of claim 13 wherein said processing unit is further configured to determine an amplitude of the first optical signal relative to an amplitude of the second optical signal from the first and second electrical signals.

15. The optical phased array transmitter of claim 6 wherein said beam processor comprises N optical signal measurement units each adapted to receive and convert a portion of one N optical signals to an electrical signal.

16. The optical phased array transmitter of claim 15 wherein N/2 optical signal measurement units are disposed along either lower or upper branches of the plurality of splitters.

17. The optical phased array transmitter of claim 16 wherein output signals of the measurement units at each split level of the plurality of splitters are coupled to one another.

18. The optical phased array transmitter of claim 6 wherein each beam processor further comprises:
a plurality of amplitude controllers each adapted adjust an amplitude of one of the N optical signals.

19. An optical phased array receiver comprising:
K optical receive elements;
K optical signal splitters each associated with one of the K optical receive elements and adapted to split an optical signal received by the associated receive elements into N optical signals;
a phase shifter network responsive to the N×K optical signals supplied by the optical signal splitters and adapted to shift phases of at least a subset of the N×K optical signals, said phase shifter network supplying, in response, N groups of associated output optical signals each comprising K optical signals selected from a different one of the K optical signal splitters;
N optical signal combiners each adapted to combine the K optical signals of a different one of the N groups to generate a combined signal.

20. The optical phased array receiver of claim 19 wherein a difference between phases of each pair of associated optical signals supplied by the phase shifter network is a same.

21. The optical phased array receiver of claim 20 further comprising:
N photodetectors each adapted to convert a different one of the N combined signals into a current signal.

22. The optical phased array receiver of claim 21 further comprising:
a processor adapted to form an image of an object using the N current signals.

23. The optical phased array receiver of claim 19 further comprising:
K optical gain stages each adapted to amplify a different one of the K optical signals received by the K optical receive elements.

24. The optical phased array receiver of claim 19 further comprising:
An amplitude control network responsive to the N×K optical signals supplied by the optical signal splitters and adapted to adjust amplitudes of at least a subset of the N×K optical signals, said amplitude control network supplying, in response, the N groups of associated output optical signals each comprising the K optical signals selected from a different one of the K optical signal splitters.

25. An optical phased array receiver comprising:
K optical receive elements;
K optical signal splitters each associated with one of the K optical receive elements and adapted to split an optical signal received by the associated receive element into N optical signals;
a first

Assignees

• California Inst Of Techn

Inventors

• Fatemi Seyed Mohammadreza
• Khachaturian Aroutin
• Hajimiri Seyed Ali

Classifications

• G02F1/292 Primary

  by controlled diffraction or phased-array beam steering (controlled diffraction for optical switching G02F1/31) · CPC title

• H04B10/40 Primary

  Transceivers · CPC title

• H04B10/572

  Wavelength control · CPC title

• H04B10/61

  Coherent receivers · CPC title