Optical MIMO Receiver Using Stokes Vector Measurements

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In optical communication systems using polarization-division multiplexing (PDM), the polarization modes tend to undergo random and unpredictable rotations and losses due to stress in the glass fiber, ambient temperature changes, and other non-idealities, leading to signal mixing at the receiver.

Innovation Solution

The implementation of an optical multiple-input-multiple-output (MIMO) receiver that performs demultiplexing based on measured Stokes parameters, using a Stokes measurement apparatus to generate measurements which are then used by an optical MIMO demultiplexer to generate demultiplexed output light signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If polarization-division multiplexing is used to increase communication capacity, then communication capacity and photon efficiency are improved, but polarization modes undergo random rotations and losses causing signal mixing

Engineering Contradiction:

Improvecommunication capacityVSAvoidsignal integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where Stokes parameter measurements are continuously fed back to adjust the MIMO demultiplexer weights, enabling adaptive compensation of polarization mode rotations and losses in real-time

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the demultiplexer weights based on measured Stokes parameters to adapt to varying polarization conditions, transforming the fixed demultiplexer into a reconfigurable system that tracks polarization fluctuations

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If Stokes parameter measurements are performed at the full signal bandwidth, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

ImproveStokes parameter measurement accuracyVSAvoidreceiver complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the measurement task by using a lower-bandwidth Stokes measurement apparatus to capture polarization state information, which is then processed to generate control signals for the MIMO demultiplexer, separating the measurement function from the full-speed signal processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary approach where Stokes parameters serve as a compressed representation of polarization state, allowing the system to infer full polarization information from reduced-bandwidth measurements through mathematical relationships

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a lower bandwidth Stokes measurement apparatus is used, then device complexity is reduced, but the ability to track fast polarization changes deteriorates

Engineering Contradiction:

Improvemeasurement apparatus complexityVSAvoidpolarization tracking speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The system performs preliminary Stokes parameter measurements at reduced bandwidth to establish baseline polarization state information, which is then used to initialize or guide faster MIMO demultiplexer operations, preparing the system in advance for rapid polarization changes

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively unmixes the signals at the receiver, improving signal integrity and communication capacity by accurately tracking polarization fluctuations and adapting the demultiplexing process accordingly.

Implementation Method 1

a Stokes measurement apparatus configured to generate measurements of Stokes parameters

Methodology Applied

Scientific EffectStokes parameters measurement:

Implementation Method 2

multiplexing techniques (such as polarization-division multiplexing (PDM)) can increase communication capacity and/or photon efficiency by multiplexing different signals over different channels (e.g., different polarization modes on the same carrier frequency)

Methodology Applied

Scientific EffectPolarization-division multiplexing: Polarisation

Data Source

PatentUS20250184009A1Optical multiple-input-multiple-output (MIMO) receiver using stokes vector measurements

Publication Date: 2025.06.05 ALOE SEMICONDUCTOR INC

AI summary

An optical multiple-input-multiple-output (MIMO) receiver includes an input port configured to receive input light; a Stokes measurement apparatus configured to generate measurements of Stokes parameters; an optical MIMO demultiplexer configured to generate a plurality of demultiplexed output light signals based on (i) the input light and (ii) the measurements of the Stokes parameters generated by the Stokes measurement apparatus; and a plurality of output ports configured to output the plurality of demultiplexed output light signals generated by the optical MIMO demultiplexer. In particular, the Stokes measurement apparatus is connected to the optical MIMO demultiplexer in a parallel arrangement.