Optical Host-Module Interface FIR Tuning for Signal Integrity

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Solution Overview

Problem

Existing communication systems face challenges in optimizing electrical interfaces between host devices and optical modules for advanced signal integrity, particularly in high-bandwidth applications like PAM4 50G, due to varying channel conditions and the need for precise tuning of FIR filters and other transmitter parameters.

Innovation Solution

A method and system that optimizes the electrical interface by iteratively testing different FIR filter settings at the host transmitter, leveraging the module's signal integrity measurement capabilities to determine the best configuration, using techniques such as Signal-to-Noise Ratio (SNR), Pulse Response, or Machine Learning, and utilizing the Common Management Interface Specification (CMIS) for communication and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual calibration with a golden receiver is performed at manufacturing time, then signal integrity is optimized, but manufacturing complexity and time increase

Engineering Contradiction:

Improvesignal integrityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically testing different FIR filter settings and selecting the optimal configuration based on measured signal quality, eliminating the need for manual calibration with golden receivers at manufacturing time

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The optimal FIR filter settings are determined and stored in lookup tables during manufacturing, allowing the system to quickly retrieve pre-determined optimal settings during operation without performing complex calibration procedures

Inventive Principle:

Principle #10Preliminary action

2Reliability

If FIR filter settings are optimized at installation time with actual receivers, then signal integrity is improved, but installation time and complexity increase

Engineering Contradiction:

Improvesignal integrityVSAvoidinstallation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Optimal FIR filter settings are pre-determined and stored in lookup tables during manufacturing, allowing the system to quickly retrieve and apply appropriate settings during installation without performing time-consuming optimization procedures

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system measures signal quality metrics and uses this feedback to automatically select the optimal FIR filter settings from pre-stored lookup tables, enabling rapid adaptation to different receiver hardware variations

Inventive Principle:

Principle #23Feedback

3Reliability

If Auto-Negotiation and Link Training protocols are used during initialization, then signal integrity is optimized, but initialization time increases

Engineering Contradiction:

Improvesignal integrityVSAvoidinitialization time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Optimal FIR filter settings are pre-determined and stored in lookup tables during manufacturing, allowing the system to quickly retrieve and apply appropriate settings during initialization without performing time-consuming optimization procedures

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #23Feedback

4Reliability

If multiple FIR filter settings are tested to find the optimal configuration, then signal integrity is improved, but processing time increases

Engineering Contradiction:

Improvesignal integrityVSAvoidconfiguration speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Multiple FIR filter settings are pre-tested and their performance characteristics are stored in lookup tables during manufacturing, allowing the system to quickly retrieve the optimal setting based on measured signal quality without performing exhaustive testing during operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4186208B1Optimizing host/module interface

Publication Date: 2025.12.31 MARVELL ASIA PTE LTD

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Figure 1A
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AI summary

Embodiments address optimization of an electrical interface between an optical host device and an optical module device at installation time. Certain methods try each entry in a set of Finite Impulse Response (FIR) filter settings at the host transmitter, while asking the module to measure the signal integrity for each. The module will then provide an indication of which entry was the best choice for signal integrity in the current hardware configuration. Note that for the module to host electrical interface, this same technique can be used in reverse, whereby the host asks the module to configure its transmitting FIR filter, and the host records and keeps track of which filter setting is the best, and then configures the module with that filter setting. In both cases, for modules supporting CMIS (Common Management Interface Specification) for module configuration and control, methods are provided.