Optical conversion system and method with multiple phase processing

Patent metadata

Field	Value
Publication number	US-9356704-B1
Application number	US-201313963899-A
Country	US
Kind code	B1
Filing date	Aug 9, 2013
Priority date	Aug 9, 2013
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A photonic processor can include a first input for a phase-modulated optical pulse signal, a second input for an optical reference signal, and a plurality of states. Each stage is configured to receive the phase-modulated optical pulse signal and a phase-delayed version of the optical reference signal. The phase-delayed version is phase-delayed in accordance with a phase position of the stage. Each stage is comprised of a reference path, a signal path, a coupler and a balanced photo detector. The coupler receives the phase-modulated optical pulse signal and provides as stage phase-modulated optical pulse signal to the signal path. The signal path is coupled to a first input of the balanced photo detector. The coupler also receives the phase-delayed version and provides a stage optical reference signal to the reference path. The reference path is coupled to a second input of the detector. The detector provides an electronic output signal corresponding to a phase relationship.

First claim

What is claimed is:

1. A photonic processor, comprising:
a first input configured to receive a phase-modulated optical pulse signal;
a second input configured to receive an optical reference signal;
a plurality of stages, each stage being configured to receive the phase-modulated optical pulse signal and a phase-delayed version of the optical reference signal, the phase-delayed version of the optical reference signal being phase-delayed in accordance with a phase position of the stage, wherein each stage is comprised of:
a reference coupler;
a phase delay;
a signal coupler;
a reference source path;
a signal source path;
a reference path;
a signal path, wherein the signal coupler is coupled to the signal path, to the signal source path and to a signal source path of the next stage, and wherein the reference coupler is coupled to the reference path, to the phase delay and to a reference source path of the next stage, wherein the phase delay is coupled to the reference coupler of the preceding stage;
a directional coupler coupled to the reference coupler and the signal coupler and used to interferometrically combine the phase-modulated optical pulse signal and the phase-delayed version of the optical reference signal for the stage; and
a balanced photo detector coupled to the directional coupler, wherein the balanced photo detector provides an electronic output signal corresponding to a phase relationship of the phase-delayed version of the optical reference signal and the phase-modulated optical pulse signal for the stage;

a first stage having a variable phase delay, the first stage being provided before the plurality of stages; and
a second stage being after the first stage and before the plurality of stages, wherein a reference signal received by an optical coupler in the second stage has a same phase as a reference signal received by an optical coupler in the first stage.

2. The photonic processor according to claim 1 , wherein the phase delay in each stage provides an equal phase delay.

3. The photonic processor according to claim 2 , wherein the balanced photo detector is at least one pair of photo diodes.

4. A photonic processor, comprising:
a first input configured to receive a phase-modulated optical pulse signal;
a second input configured to receive an optical reference signal; and
a first set of a plurality of stages, each stage of the first set being configured to receive the phase-modulated optical pulse signal and a phase-delayed version of the optical reference signal, the phase-delayed version of the optical reference signal being phase-delayed in accordance with a phase position of each stage among the first set of stages, wherein each stage of the first set is comprised of:
a reference path;
a signal path;
a directional coupler coupled to the reference path and the signal path and used to interferometrically combine the phase-modulated optical pulse signal and the phase-delayed version of the optical reference signal;
a balanced photo detector coupled to the directional coupler, wherein the balanced photo detector provides an electronic output signal corresponding to a phase relationship of the phase-delayed version of the optical reference signal and the phase-modulated optical pulse; and

a second set of a plurality of stages, each stage of the second set being configured to receive the phase-modulated optical pulse signal and a version of the optical reference signal, wherein each stage of the second set is comprised of:
a reference path;
a signal path;
a directional coupler coupled to the reference path and the signal path and used to interferometrically combine the phase-modulated optical pulse signal and the version of the optical reference signal; and
a balanced photo detector coupled to the directional coupler, wherein the balanced photo detector provides an electronic output signal corresponding to a phase relationship of the version of the optical reference signal and the phase-modulated optical pulse signal;

wherein the second set of stages comprises a first stage having a variable phase delay serving to eliminate spurious phase variations in the signal paths and the reference paths, and a second stage, wherein the version of the optical reference signal received by the second stage has a same phase as the version of the optical reference signal received by the first stage.

5. The photonic processor according to claim 4 , wherein the second stage of the second set of stages is disposed after the first stage of the second set of stages and before the first set of stages.

6. A method of multi-phase processing, the method comprising:
receiving a phase-modulated optical pulse signal from a first optical coupler at a plurality of stages;
receiving a respective phase-delayed version of an optical reference signal from a second optical coupler at the plurality of stages, the respective phase-delayed version of the optical reference signal being phase-delayed in accordance with a phase position of the stage by an optical phase-delay element, wherein an input to the second optical coupler of at least one of the plurality of stages is coupled to an output of the phase-delay element of the preceding stage;
receiving a first reference signal at a first stage having a variable phase delay, the first stage being provided before the plurality of stages;
receiving a second reference signal at a second stage being after the first stage and before the plurality of stages, wherein the second reference signal is received by an optical coupler in the second stage and has a same phase as the first reference signal received by an optical coupler in the first stage;
combining and comparing the respective phase-delayed version of the optical reference signal with the phase-modulated optical pulse signal for the plurality of stages at each stage using a directional coupler and a pair of photo diodes in each stage; and
providing an electronic output signal corresponding to a phase relationship of the phase-delayed optical reference signal and the phase-modulated optical pulse signal at each stage of the plurality of stages.

7. The method according to claim 6 , wherein the optical coupler at each stage provides the respective phase-delayed version for the stage to the directional coupler and provides an output phase delayed signal to a next stage, the output phase delayed signal having a lower power level than an output phase delayed signal from a preceding stage, wherein the power level of the respective phase-delayed version for each stage is equal.

8. The method according to claim 7 , wherein the electronic output signal is provided as a thermometer output indicating a phase position of the phase-modulated optical pulse signal.

9. The method according to claim 6 , wherein each optical phase delay element is equal in phase delay.

10. A multiphase photonic processor, comprising:
a phase modulator configured to receive an electronic radio frequency signal and an optical clock signal and to provide a phase-modulated optical signal on a first signal path, wherein the optical clock signal is provided on a second signal path;
a first directional coupler;
a first signal optical coupler for providing a first level of power of the phase-modulated optical signal to a first input of the first directional coupler;
a first reference optical coupler for providing a version of the optical clock signal to a second input of the first directional coupler;
a first balanced photodetector having a first input coupled to a first output of the first directional coupler and a second input coupled to a second output of the first directional coupler;
a second directional coupler;
a second signal

Assignees

• Rockwell Collins Inc

Inventors

• Zanoni Raymond
• King Oliver S
• Chen Wenlu
• Jepsen Kim S
• Cullen Thomas J

Classifications

• G02F7/00 Primary

  Optical analogue/digital converters · CPC title

• H04B10/61

  Coherent receivers · CPC title

• H04B10/63

  Homodyne {, i.e. coherent receivers where the local oscillator is locked in frequency and phase to the carrier signal} · CPC title

• H04B10/60 Primary

  Receivers · CPC title