RLC Filter Synthesis for Electronic Dispersion Compensation

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Solution Overview

Problem

Current optical transceivers face challenges with high power consumption and cost due to the need for dispersion compensation in long-distance optical transmission, particularly with direct modulated laser (DML) based systems, which suffer from optical dispersion and chirp-related signal degradation.

Innovation Solution

The implementation of an electronic dispersion compensation (EDC) device using passive electronic components such as resistors, inductors, and capacitors in the optical receiver to mitigate optical dispersion effects, allowing for cost-effective and power-efficient signal compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If DML based optical transceivers are used for long distance transmission, then cost and power consumption are reduced, but optical dispersion and chirp cause signal degradation

Engineering Contradiction:
Improvepower consumptionVSAvoidsignal quality
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

An electronic dispersion compensation (EDC) device is introduced as an intermediary component in the optical receiver. This EDC device includes a compensating RLC filter that compensates for the signal degradation caused by optical dispersion and chirp, thereby improving signal quality without requiring expensive EML sources

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the electrical parameters (impedance, frequency response) of the received optical signal by passing it through a compensating RLC filter. The filter is designed with specific inductance, resistance, and capacitance values to counteract the dispersion effects and restore signal integrity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If EML is used for long distance transmission, then signal quality is improved, but cost increases

Engineering Contradiction:
Improvesignal qualityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

An electronic dispersion compensation (EDC) device is introduced as an intermediary component in the optical receiver. This EDC device includes a compensating RLC filter that compensates for the signal degradation caused by optical dispersion and chirp, thereby improving signal quality without requiring expensive EML sources

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a cost-effective DML source combined with a relatively simple EDC circuit (comprising basic RLC components) as an alternative to expensive EML sources. This approach achieves acceptable signal quality over long distances at a lower cost

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Length of stationary object

If dispersion compensation is implemented without EDC, then device complexity is reduced, but transmission distance is limited

Engineering Contradiction:
Improvetransmission distanceVSAvoidsystem complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameters (impedance, frequency response) of the received optical signal by passing it through a compensating RLC filter. The filter is designed with specific inductance, resistance, and capacitance values to counteract the dispersion effects and restore signal integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

An electronic dispersion compensation (EDC) device is introduced as an intermediary component in the optical receiver. This EDC device includes a compensating RLC filter that compensates for the signal degradation caused by optical dispersion and chirp, thereby improving signal quality without requiring expensive EML sources

Inventive Principle:
Principle #24Intermediary (Mediator)

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 EDC device effectively reduces transmission errors over long distances by compensating for optical dispersion, improving bit error rate performance and extending transmission distances while maintaining low power consumption and cost-effectiveness.

Implementation Method 1

the velocity of an electromagnetic wave depends on the wavelength, that is, the phase velocity varies based on frequencies

Methodology Applied
Scientific EffectOptical dispersion: Dispersion (of waves)

Implementation Method 2

a residual data-dependent phase modulation accompanying a desired intensity modulation

Methodology Applied
Scientific EffectChirp:

Implementation Method 3

Electronic dispersion compensation methods and implementations using RLC filter synthesis

Methodology Applied
Scientific EffectRLC filter synthesis: Filter (electronic)

Data Source

PatentEP3430745B1Electronic dispersion compensation methods and implementations using RLC filter synthesis
Publication Date: 2022.05.04 OE SOLUTIONS AMERICA
  • EP3430745B1 patent drawingFigure 1
  • EP3430745B1 patent drawingFigure 2A~2B
  • EP3430745B1 patent drawingFigure 3

AI summary

A method and apparatus for compensating optical dispersion over an optical fiber are provided in fiber optic communications to increase a transmission distance by overcoming the optical dispersion caused by wavelength changes of light sources and dispersion effects of a fiber. In one implementation, the present technology may be implemented in the form of a RLC passive microwave filter with no extra power consumption. By way of example, an optical receiver may include a photodiode operable to receive an optical signal and produce an electrical signal, a transimpedance amplifier (TIA) operable to receive the electrical signal and produce a first amplified signal, and an electronic dispersion compensation (EDC) device operable to receive the first amplifier signal from the TIA and compensate or reduce the effects of optical dispersion on the received electrical signal.