Optical Receiver Miniaturization via Downsampling and Optical Filtering

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Optical receivers using polarization demultiplexing techniques for 100 GbE and 40 GbE optical modules in WDM systems have complex configurations, hindering miniaturization due to the need for high-speed electrical circuits and complex reception systems.

Innovation Solution

An optical receiver design that includes an interleaver, optical/electrical converters, a downsampler, a calculator, a level adjuster, and a discriminator to process polarization multiplexed signals, eliminating the need for high-speed processing and buffer memory, thereby reducing the circuit scale and enabling miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polarization demultiplexing techniques are used in optical receivers for 100 GbE and 40 GbE optical modules, then signal processing performance is improved, but device complexity increases and miniaturization is hindered

Engineering Contradiction:

Improvesignal processing performanceVSAvoidreception system configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex high-speed electrical circuits with a photonic crystal filter-based optical filtering system. The photonic crystal filter performs polarization demultiplexing through optical interference effects rather than electrical signal processing, eliminating the need for complex high-speed electronics and buffer memory while maintaining signal processing performance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using optical frequency domain filtering instead of time-domain electrical processing. The photonic crystal filter exploits wavelength-dependent transmission characteristics to separate polarization multiplexed signals, transforming the problem from high-speed electrical processing to optical spectral filtering.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high-speed electrical circuits operating at or above the baud rate are used for polarization demultiplexing, then signal processing capability is improved, but circuit scale increases and miniaturization becomes difficult

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidcircuit scale

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

The patent substitutes electrical signal processing circuits with an optical photonic crystal filter system. The filter performs polarization demultiplexing through optical interference, eliminating the need for high-speed electrical circuits operating at baud rate or above, thereby dramatically reducing circuit scale and enabling miniaturization.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If complex reception system configurations are used for polarization demultiplexing, then demultiplexing performance is improved, but manufacturing cost increases

Engineering Contradiction:

Improvedemultiplexing performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces complex reception system configurations with a compact photonic crystal filter-based optical filtering system. This integrated optical solution achieves polarization demultiplexing performance while simplifying the overall reception system, reducing component count, and lowering manufacturing costs through miniaturization.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 design allows for the miniaturization of optical receivers using polarization demultiplexing techniques, reducing manufacturing costs and maintaining effective signal processing performance.

Implementation Method 1

an interleaver configured to split the polarization multiplexed signal into two transmitted signals that are asymmetric in terms of a light transmission characteristic

Methodology Applied

Scientific EffectPhotonic crystal filtering: Photonic Crystal

Implementation Method 2

an optical/electrical converter configured to convert the transmitted signals resulting from the split into electrical signals

Methodology Applied

Scientific EffectOptical/electrical conversion: Photoelectric Effect

Data Source

PatentUS11689294B2Optical receiver

Publication Date: 2023.06.27 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

[Problem] An optical receiver using a polarization demultiplexing technique is miniaturized.[Solution] An optical receiver 100A for receiving a polarization multiplexed signal obtained by performing orthogonal polarization multiplexing on two optical signals. The optical receiver includes an IL 1 splitting the polarization multiplexed signal into two transmitted signals that are asymmetric in terms of a light transmission characteristic, O/Es 2a and 2b converting the transmitted signals resulting from the split into electrical signals, a downsampler 3 downsampling the electrical signals resulting from the conversion to generate low-speed digital signals, a calculator 4 calculating coefficients of a polarization separation matrix from the resultant low-speed digital signals, a level adjuster 5A adjusting, in accordance with the coefficients resulting from the calculation, signal levels of the electrical signals resulting from the conversion to generate a plurality of adjustment signals, adders 6Aa and 6Ab adding the generated adjustment signals to generate addition signals, and discriminators 7a and 7b restoring and extracting the two optical signals from the generated addition signals.