Jammer-suppressed photonic-enabled RF link

Patent metadata

Field	Value
Publication number	US-10404381-B1
Application number	US-201715803533-A
Country	US
Kind code	B1
Filing date	Nov 3, 2017
Priority date	Mar 17, 2016
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A radio frequency (RF) link includes a link transmitter that includes a data modulator for modulating a data waveform together with an RF carrier, a photonic encoder coupled to the data modulator, and a transmitter antenna for transmitting an RF signal, wherein the RF signal comprises an output of the photonic encoder, and a link receiver including a receiver antenna for receiving the RF signal, a first laser source, a photonic limiter coupled to the first laser source and to the receiving antenna, a photonic decoder coupled to the photonic limiter, a photo-receiver coupled to the photonic decoder, and a demodulator coupled to the photo-receiver for demodulating an output of the photo-receiver with the RF carrier to form a data output.

First claim

What is claimed is:

1. A receiver for an RF link that receives an RF signal and an interferer signal, the receiver comprising:
an optical modulator;
a photonic limiter coupled to the optical modulator; and
a photonic decoder coupled to the photonic limiter;
wherein the optical modulator modulates an optical carrier with the RF signal and with the interferer and produces modulation sidebands associated with the RF signal and modulation sidebands associated with the interferer;
wherein the photonic limiter attenuates modulation sidebands associated with the interferer by a greater amount than the photonic limiter attenuates the modulation sidebands associated with the RF signal; and
wherein the photonic decoder phase modulates the attenuated modulation sidebands associated with the interferer to spread energy of the attenuated modulation sidebands associated with the interferer over a first bandwidth, and phase modulates the attenuated modulation sidebands associated with the RF signal to spread energy of the attenuated modulation sidebands associated with the RF signal over a second bandwidth, wherein the second bandwidth is narrower than the first bandwidth.

2. The receiver of claim 1 wherein the photonic limiter comprises:
at least one optical waveguide configured to reflect light as a result of stimulated Brillouin scattering; and
wherein the stimulated Brillouin scattering attenuates modulation sidebands associated with the interferer by a greater amount than the stimulated Brillouin scattering attenuates the modulation sidebands associated with the RF signal.

3. The receiver of claim 1 wherein the photonic decoder comprises:
a 1 to N splitter coupled to the photonic limiter;
N first optical delays, wherein the nth first optical delay has a value derived from n×ΔT, where ΔT is a code-chip interval;
wherein a time-staggered serial-to-parallel conversion achieved by the 1×N splitter and the N first optical delays enable simultaneous extraction of a subset of N successive code-chips out of a total of M code-chips in an encoded waveform, and wherein the nth first optical delay views an (m+n) th code-chip of a code-chip waveform;
N second optical delays, wherein the nth second optical delay has a value that is an inverse of a time-delay code for a (m+n) th chip of the code chip waveform; and
a photo-receiver.

4. The receiver of claim 3 :
wherein each first optical delay of the N first optical delays in the photonic decoder is coupled to the 1 to N splitter;
wherein the nth second optical delay of the N second optical delays is coupled to the nth first optical delay of the N first optical delays; and
wherein the N second optical delays are coupled to the N to 1 combiner and wherein an output of the N to 1 combiner is coupled to the photo-receiver.

5. The receiver of claim 3 further comprising:
a code match detect circuit coupled to the photo-receiver; and
a code select controller coupled to the code match detect circuit and to the N second optical delays.

6. The receiver of claim 3 :
wherein the N second optical delays of the photonic decoder are coupled to the 1 to N splitter;
wherein the nth second optical delay of the N second optical delays is coupled to the nth first optical delay of the N first optical delays;
wherein a N to 1 combiner is coupled to the N first optical delays; and
wherein an output of the N to 1 combiner is coupled to the photo-receiver.

7. The receiver of claim 3 wherein the photo-receiver of the photonic decoder comprises:
a photodetector; and
a RF bandpass filter.

8. The receiver of claim 3 wherein the photo-receiver of the photonic decoder comprises:
N photo-detectors, wherein the nth photo-detector is coupled to the nth second optical delay of the N second optical delays;
N preamplifiers, wherein the nth preamplifier is coupled to the nth photo-detector; and
a summing amplifier coupled to each of the N preamplifiers.

Assignees

• Hrl Lab Llc

Inventors

• Yap Daniel

Classifications

• H04B10/00 Primary

  Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication · CPC title

• H04B2210/006

  Devices for generating or processing an RF signal by optical means · CPC title

• H04B10/2575

  Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier · CPC title

• H04B10/503

  Laser transmitters · CPC title

• H04B10/697 Primary

  Arrangements for reducing noise and distortion · CPC title