Integrated Coherent Optical Receiver Circuit for Pol Mux DQPSK Signals

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Solution Overview

Problem

Current optical receiver systems for polarization multiplexed differential quadrature phase-shift keying (Pol Mux DQPSK) signals are complex, require multiple substrates, and lack a compact integrated design, which complicates manufacturing, increases costs, and reduces reliability.

Innovation Solution

A coherent optical receiver circuit with integrated components on a common substrate, featuring a polarization demultiplexer, optical hybrid circuits, and demultiplexing and delay circuitry, which demultiplexes and processes Pol Mux DQPSK signals efficiently, using polarization beam splitters and arrayed waveguide gratings to separate and delay optical signals by wavelength without electrical conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If optical receiver components are provided on multiple substrates, then manufacturing flexibility is maintained, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvenumber of substratesVSAvoidmanufacturing complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent integrates multiple optical receiver components (polarization demultiplexer, optical hybrid circuits, demultiplexing and delay circuitry) onto a single common substrate. This merging of previously separate components into one integrated photonic circuit reduces the number of substrates from multiple to one, thereby reducing device complexity while simplifying manufacturing processes and lowering costs.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If optical receiver components are integrated on a common substrate, then manufacturing is simplified and costs are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidintegration precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs photonic integration techniques that replace traditional mechanical assembly of discrete optical components with monolithic integration on a common substrate. This approach uses semiconductor fabrication processes to create waveguides, couplers, and other optical structures directly on the substrate, thereby simplifying manufacturing while managing precision requirements through standardized fabrication processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If discrete components are used in optical receivers, then component replacement is easier, but system reliability decreases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidcomponent replacement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

By integrating multiple optical components onto a single common substrate, the patent creates a unified photonic circuit where components cannot be individually replaced but function as a coordinated system. This integration improves reliability by eliminating connection interfaces between separate components and reducing alignment errors, while the entire integrated circuit can be replaced as a single unit if needed.

Inventive Principle:
Principle #5Merging (Combining)

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 provides a compact, reliable, and cost-effective optical receiver that simplifies manufacturing and improves data processing efficiency for high-data-rate WDM systems by integrating all necessary components on a single substrate, enhancing the receiver's ability to handle Pol Mux DQPSK signals and other modulation formats.

Implementation Method 1

polarization beam splitters and arrayed waveguide gratings to separate and delay optical signals by wavelength

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

arrayed waveguide gratings to separate and delay optical signals by wavelength

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

convert the optical signals into electrical signals

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2446309B1Optical receiver integrated on a substrate
Publication Date: 2015.07.29 INFINERA CORP
  • EP2446309B1 patent drawingFigure 1
  • EP2446309B1 patent drawingFigure 2
  • EP2446309B1 patent drawingFigure 3

AI summary

A coherent optical receiver circuit (100) is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate (110). Further integration is achieved by incorporating various optical demultiplexer (112) designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals.