Phase change detection in optical signals

Patent metadata

Field	Value
Publication number	US-2019319714-A1
Application number	US-201916377927-A
Country	US
Kind code	A1
Filing date	Apr 8, 2019
Priority date	Apr 12, 2018
Publication date	Oct 17, 2019
Grant date	—

Abstract

Optical signal receivers and methods are provided that include multiple optical resonators, each of which receives a portion of an arriving optical signal. Various of the optical resonators are tuned or detuned from a carrier wavelength, and produce an intensity modulated output signal in response to modulation transitions in the arriving optical signal. A detector determines phase transitions in the arriving optical signal, by analyzing the intensity modulation output signals from the optical resonators, and distinguishes between differing phase transitions that result in a common final state of the arriving optical signal.

First claim

What is claimed is:

1 . An optical signal receiver comprising:
a first optical resonator configured to receive an arriving optical signal, and to emit first output optical signal energy in response to receiving the arriving optical signal; a second optical resonator configured to receive the arriving optical signal, and to emit second output optical signal energy in response to receiving the arriving optical signal; and a detector configured to determine a phase transition in the arriving optical signal based upon a transient response in at least one of the first output optical signal energy and the second output optical signal energy.

2 . The optical signal receiver of claim 1 wherein the detector is further configured to distinguish a magnitude and a direction of the phase transition, and to uniquely identify the magnitude and direction of the phase transition from among a set of candidate phase transitions, the set of candidate phase transitions being a set of phase transitions that result in a common final state of the arriving optical signal.

3 . The optical signal receiver of claim 1 wherein the detector is further configured to distinguish phase transitions of 360° or greater.

4 . The optical signal receiver of claim 1 wherein each of the first and second optical resonators is an etalon having two semi-reflective surfaces configured to at least partially trap optical signal energy by reflecting a portion of the optical signal energy impinging upon each of the semi-reflective surfaces.

5 . The optical signal receiver of claim 1 further comprising a third optical resonator configured to receive the arriving optical signal and to emit third output optical signal energy in response to receiving the arriving optical signal, wherein the detector is configured to determine the phase transition based at least in part upon a comparison between at least two of the first output optical signal energy, the second output optical signal energy, and the third output optical signal energy.

6 . A method of detecting information encoded in an optical signal, the method comprising:
receiving a portion of the optical signal at each of a plurality of optical resonators; analyzing a respective output optical signal from each of the plurality of optical resonators; and determining a phase transition in the optical signal based on one or more variations in intensity level of one or more of the output optical signals.

7 . The method of claim 6 wherein determining the phase transition includes uniquely identifying a magnitude and a direction of the phase transition from among a set of candidate phase transitions, the set of candidate phase transitions being a set of phase transitions that result in a common final state of the arriving optical signal.

8 . The method of claim 6 wherein determining the phase transition includes distinguishing phase transitions of 360° or greater.

9 . The method of claim 6 wherein each of the plurality of optical resonators is an etalon having two semi-reflective surfaces, and further comprising:
producing the respective output optical signal from each of the plurality of optical resonators by resonating optical signal energy inside each of the plurality of optical resonators by reflecting a portion of the optical signal energy impinging upon each of the semi-reflective surfaces.

10 . A method of transmitting information, comprising:
providing an optical signal with an initial state having an initial phase and an initial amplitude; modulating the optical signal from the initial state to a final state through a first phase transition having a first amount of change in phase and a first direction of change in phase to represent a first information symbol; and modulating the optical signal from the initial state to the final state through a second phase transition having a second amount of change in phase and a second direction of change in phase to represent a second information symbol, the second information symbol being different from the first information signal.

Assignees

• Raytheon Co

Inventors

• Kowalevicz Andrew
• Graceffo Gary M
• Dolgin Benjamin P

Classifications

• H04B10/11

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B10/615

  Arrangements affecting the optical part of the receiver · CPC title

• H04B10/612 Primary

  for optical signals modulated with a format different from binary or higher-order PSK [X-PSK], e.g. QAM, DPSK, FSK, MSK, ASK · CPC title

• H04B10/677 Primary

  for differentially modulated signal, e.g. DPSK signals · CPC title

• H04B10/5561

  Digital phase modulation · CPC title