Polarization Beam Splitter Rotator Structure for TE TM Mode Purification

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Solution Overview

Problem

Optical devices in fiber optic telecommunications often introduce errors due to inefficiencies in splitting and rotating TE and TM polarization modes, leading to suboptimal performance and increased costs.

Innovation Solution

A polarization beam splitter-assisted polarization rotator-polarization beam combiner structure that splits, rotates, and recombines TE and TM modes to separate and purify the primary modes, reducing error components and enhancing homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a polarization beam splitter is used to split TE and TM modes, then the polarization modes can be manipulated independently, but error components are introduced due to inefficient splitting

Engineering Contradiction:
Improveindependent manipulation of polarization modesVSAvoidsignal error components
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts and removes error components from the optical signal using a second polarization beam splitter. The system separates the desired polarization modes from the error components introduced by the first beam splitter, effectively taking out the harmful elements from the signal path.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Polarization rotators are introduced as intermediary devices between the beam splitters to rotate the polarization states of error components, enabling their separation from the main signal. This intermediary action facilitates the removal of error components through the second beam splitter.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a polarization rotator is used to rotate polarization modes, then the modes can be redirected, but error components are introduced due to inefficient rotation

Engineering Contradiction:
Improvepolarization mode redirectionVSAvoidsignal error components
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts error components generated by the polarization rotator using the second polarization beam splitter. By rotating the error components to different polarization states and separating them, the system removes these harmful elements while preserving the main signal.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system implements a feedback mechanism where error components are continuously identified, rotated to appropriate states, and removed. This closed-loop approach ensures that polarization errors are actively managed and eliminated from the signal path.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If polarization modes are split and rotated, then independent manipulation is achieved, but the device complexity increases

Engineering Contradiction:
Improveindependent polarization manipulationVSAvoidoptical structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the optical system into distinct functional modules: a first polarization beam splitter for initial separation, polarization rotators for state modification, and a second polarization beam splitter for error removal. This segmentation allows independent optimization of each component while achieving overall system functionality.

Inventive Principle:
Principle #1Segmentation

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

The solution effectively purifies the optical signal by separating undesired polarization errors, resulting in a highly purified primary output with only second-order error modes remaining, thereby improving the performance and reducing costs associated with polarization sensitivity.

Implementation Method 1

Light is a vector field that has two primary and orthogonal polarization states or vector directions. Generally, the polarization states are referred to as the S and P polarizations in free space optics, or the TE (Transverse Electric) and TM (Transverse Magnetic) modes of optical waveguides.

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

An apparatus and method for substantially removing the error components of an optical signal from the primary orthogonal components

Methodology Applied
Scientific EffectPolarization rotation: Polarisation

Data Source

PatentEP2232316B1Polarization beam splitter-polarization rotator structure
Publication Date: 2016.02.17 INFINERA CORP
  • EP2232316B1 patent drawingFigure 1
  • EP2232316B1 patent drawingFigure 2~3
  • EP2232316B1 patent drawingFigure 4

AI summary

A polarization beam splitter-polarization rotator-polarization beam combiner optical structure comprising a pair of polarization rotators having a polarization beam splitter associated with the input ends of the two polarization rotators, and a polarization beam combiner associated with output ends of the two polarization rotators, and a method of purifying a light signal comprising TE and TM modes by disassociating the primary TE and TM modes from first order splitter and rotation error components.