Receiver Optical Sub-Assembly Ground Filtering for Crosstalk Isolation

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Solution Overview

Problem

Existing receiver optical sub-assemblies in optical communication networks face significant challenges in reducing electromagnetic crosstalk, particularly in complex electromagnetic radiation environments, which affects signal sensitivity and system performance.

Innovation Solution

The implementation of a receiver optical sub-assembly that includes a photodiode, a trans-impedance amplifier, and multiple filter components strategically connected to ground and power terminals to filter out electromagnetic crosstalk signals, forming independent signal loops and utilizing direct and alternating current grounding to enhance anti-electromagnetic interference performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the receiver optical sub-assembly is placed in a complex electromagnetic radiation environment to meet network throughput requirements, then the network bandwidth and data transmission capability are improved, but electromagnetic crosstalk interference increases and signal sensitivity deteriorates

Engineering Contradiction:

Improvenetwork throughputVSAvoidelectromagnetic crosstalk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces filter components as intermediary elements between the trans-impedance amplifier and the external ground. These filter components act as mediators that selectively block electromagnetic crosstalk signals while allowing legitimate signal frequencies to pass through, thereby protecting the receiver optical sub-assembly from harmful electromagnetic interference in high-throughput network environments

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The grounding system is segmented into multiple independent paths: a first ground terminal directly connected to external ground for DC grounding, and a second ground terminal connected through filter components for AC grounding. This segmentation allows different frequency components to be handled separately, effectively isolating electromagnetic crosstalk from the sensitive photodiode and trans-impedance amplifier circuits

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If traditional grounding methods are used in the receiver optical sub-assembly, then the structure is simple and easy to manufacture, but anti-electromagnetic interference performance is insufficient

Engineering Contradiction:

Improvegrounding structure simplicityVSAvoidanti-electromagnetic interference performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The grounding system is divided into multiple independent ground terminals (first ground terminal and second ground terminal) with different connection methods. The first ground terminal provides direct DC grounding for stability, while the second ground terminal uses filter components for AC signal filtering. This segmented approach maintains manufacturing simplicity while significantly improving electromagnetic interference rejection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different grounding strategies are applied to different parts of the circuit: the first ground terminal uses direct connection for low-frequency stability, while the second ground terminal uses filter components for high-frequency noise rejection. This local differentiation of grounding quality allows each part to be optimized for its specific frequency range without complicating the overall manufacturing process

Inventive Principle:

Principle #3Local quality

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 configuration effectively reduces electromagnetic crosstalk interference, improving the sensitivity and reliability of the receiver optical sub-assembly by isolating and absorbing crosstalk signals across all signal paths, thereby enhancing the overall anti-electromagnetic interference performance.

Implementation Method 1

a photodiode configured to convert an optical signal into an electrical signal

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

The first filter component can filter out an electromagnetic crosstalk signal from a ground

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Data Source

PatentUS11848710B2Receiver optical sub-assembly, bi-directional optical sub-assembly, optical module, and optical network device

Publication Date: 2023.12.19 HUAWEI TECH CO LTD

AI summary

This application provides a receiver optical sub-assembly, a bi-directional optical sub-assembly, and an optical network device to improve anti-electromagnetic crosstalk performance of the receiver optical sub-assembly. The receiver optical sub-assembly includes: a photodiode, a trans-impedance amplifier, and a first filter component. The photodiode is configured to convert an optical signal into an electrical signal, a positive electrode of the photodiode is connected to an input terminal of the trans-impedance amplifier, and a negative electrode of the photodiode is configured to connect to a power supply. The trans-impedance amplifier is configured to amplify the electrical signal output by the photodiode, a power terminal of the trans-impedance amplifier is configured to connect to a power supply, and a first ground terminal of the trans-impedance amplifier is configured to connect to an external ground.