Communications device with optical injection locking source and related methods

Patent metadata

Field	Value
Publication number	US-9859678-B2
Application number	US-201414494051-A
Country	US
Kind code	B2
Filing date	Sep 23, 2014
Priority date	Sep 23, 2014
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A communications device may include a remote device having a first E/O modulator to modulate an optical carrier signal with an input signal having a first frequency, an optical waveguide coupled to the remote device, and a local device coupled to the optical waveguide. The local device may include an optical source to generate the optical carrier signal, a second E/O modulator to modulate the optical carrier signal with a reference signal to generate a modulated reference signal, an OIL source coupled to the second E/O modulator and to amplify the modulated reference signal, and an O/E converter coupled to the OIL source and to generate an output signal including a replica of the input signal at a second frequency based upon the reference signal.

First claim

That which is claimed is:

1. A communications device comprising:
a remote device comprising
a first electro-optic (E/O) modulator configured to modulate an optical carrier signal with an input signal having a first frequency to generate a modulated optical carrier signal, and
an optical waveguide coupled to said remote device; and

a local device coupled to said optical waveguide and comprising
an optical source configured to generate the optical carrier signal,
a first band pass filter having an input configured to receive the modulated optical carrier signal for generating a modulated and filtered optical carrier signal,
a second E/O modulator configured to modulate the modulated and filtered optical carrier signal with a reference signal to generate a modulated reference signal,
an optical injection locking (OIL) source coupled to said second E/O modulator and configured to amplify the modulated reference signal, and
an O/E converter coupled to said OIL source and configured to generate an output signal comprising a replica of the input signal at a second frequency based upon the reference signal,
said first band pass filter having first and second outputs respectively coupled to said second E/O modulator and said 0/E converter.

2. The communications device of claim 1 wherein said second E/O modulator is configured to generate the modulated reference signal to comprise a plurality of harmonics; and wherein said OIL source is configured to amplify a selected harmonic from the plurality thereof.

3. The communications device of claim 1 wherein said first band pass filter is configured to pass a carrier frequency sideband; and wherein said local device comprises
a second band pass filter coupled downstream from said second E/O modulator and configured to pass a reference signal frequency sideband.

4. The communications device of claim 1 wherein the first frequency is less than the second frequency.

5. The communications device of claim 1 wherein the first frequency is greater than the second frequency.

6. The communications device of claim 1 wherein said O/E converter comprises:
first and second optical detectors coupled to said OIL source; and
a combiner coupled to said first and second optical detectors.

7. The communications device of claim 1 wherein said local device comprises an amplifier coupled between said optical source and said first and second E/O modulators.

8. The communications device of claim 1 wherein said local device comprises a local oscillator configured to generate the reference signal.

9. The communications device of claim 1 wherein said remote device further comprises an antenna coupled to said first E/O modulator.

10. A communications device comprising:
a remote device comprising
a first electro-optic (E/O) modulator configured to modulate an optical carrier signal with an input signal having a first frequency to generate a modulated optical carrier signal, and
an optical waveguide coupled to said remote device; and

a local device coupled to said optical waveguide and comprising
an optical source configured to generate the optical carrier signal,
a first band pass filter coupled downstream from said first E/O modulator and configured to pass a carrier frequency sideband, said first band pass filter having an input configured to receive the modulated optical carrier signal for generating a modulated and filtered optical carrier signal,
a second E/O modulator configured to modulate the modulated and filtered optical carrier signal with a reference signal to generate a modulated reference signal comprising a plurality of harmonics,
a second band pass filter coupled downstream from said second E/O modulator and configured to pass a reference signal frequency sideband,
an optical injection locking (OIL) source coupled to said second E/O modulator and configured to amplify a selected harmonic from the plurality thereof from the modulated reference signal, the selected harmonic being in the reference signal frequency sideband, and
an O/E converter coupled to said OIL source and configured to generate an output signal comprising a replica of the input signal at a second frequency based upon the reference signal,
said first band pass filter having first and second outputs respectively coupled to said second E/O modulator and said O/E converter.

11. The communications device of claim 10 wherein the first frequency is less than the second frequency.

12. The communications device of claim 10 wherein the first frequency is greater than the second frequency.

13. The communications device of claim 10 wherein said O/E converter comprises:
first and second optical detectors coupled to said OIL source; and
a combiner coupled to said first and second optical detectors.

14. The communications device of claim 10 wherein said local device comprises an amplifier coupled between said optical source and said first and second E/O modulators.

15. The communications device of claim 10 wherein said local device comprises a local oscillator configured to generate the reference signal.

16. The communications device of claim 10 wherein said remote device further comprises an antenna coupled to said first E/O modulator.

17. A communications method comprising:
generating an optical carrier signal with an optical source;
electro-optic (E/O) modulating, in a remote device with a first E/O modulator, the optical carrier signal with an input signal having a first frequency to generate a modulated optical carrier signal;
using a first band pass filter having an input to receive the modulated optical carrier signal for generating a modulated and filtered optical carrier signal;
E/O modulating, in a local device coupled to the remote device via an optical waveguide with a second E/O modulator, the modulated and filtered optical carrier signal with a reference signal to generate a modulated reference signal;
amplifying the modulated reference signal with an optical injection locking (OIL) source; and
generating with an O/E converter an electrical output signal comprising a replica of the input signal at a second frequency based upon the reference signal at the local device, the first band pass filter having first and second outputs respectively coupled to the second E/O modulator and the O/E converter.

18. The communications method of claim 17 wherein the modulated reference signal comprises a plurality of harmonics; and wherein the OIL source amplifies a selected harmonic from the plurality thereof.

19. The communications method of claim 17 further comprising:
using the first band pass filter to pass a carrier frequency sideband; and
using a second band pass filter to pass a reference signal frequency sideband.

20. The communications method of claim 17 wherein the first frequency is less than the second frequency.

21. The communications method of claim 17 wherein the first frequency is greater than the second frequency.

22. The communications method of claim 17 further comprising amplifying an output of the optical source.

23. The communications method of claim 17 further comprising generating the reference signal with a local oscillator.

Assignees

• Harris Corp

Inventors

• Middleton Charles
• Desalvo Richard
• Meredith Scott L
• Scheuter Peter S

Classifications

• H04B10/25758 Primary

  between a central unit and a single remote unit by means of an optical fibre · CPC title

• H01S5/0085 Primary

  for modulating the output, i.e. the laser beam is modulated outside the laser cavity · CPC title