Optical Coupling for High-Speed Vehicle Data Isolation
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Solution Overview
Problem
Existing isolation solutions for vehicles, particularly aircraft, are inadequate in addressing transient and spurious voltages caused by lightning strikes, as they are too large, have low data transmission rates, and introduce losses and distortions, making it difficult to integrate high-speed digital communication while ensuring electrical isolation.
Innovation Solution
An isolated high-speed digital interface using optical coupling between input and output terminals, with separate power supplies and no electrically conductive path, enabling bi-directional communication at high speeds while maintaining electrical isolation through optical transmitters and receivers, and optionally using an air gap or fiber-optic links for isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical isolators are used for electrical isolation, then transient voltages are isolated, but data transmission rates are unacceptably low
Solution Approach 1:
The patent replaces traditional electrical isolation methods (transformers, capacitive couplers) with an optical isolation system using VCSELs and photodetectors. This substitution enables high-speed data transmission (up to 40 Gbps) while maintaining effective electrical isolation, as optical signals are immune to electromagnetic coupling and transient voltage effects.
Solution Approach 2:
The invention changes the fundamental parameter of signal transmission from electrical to optical domain. By using vertical-cavity surface-emitting lasers (VCSELs) operating at specific wavelengths and photodetectors with corresponding sensitivity, the system achieves both high transmission rates and complete electrical isolation, resolving the contradiction between speed and isolation effectiveness.
2Reliability
If transformer isolation techniques are used, then electrical isolation is provided, but losses and distortions increase for extended cable runs
Solution Approach 1:
The patent substitutes transformer-based electrical isolation with optical isolation using VCSELs and photodetectors. This eliminates the electromagnetic coupling losses and signal distortions inherent in transformer isolation, particularly for cable runs exceeding 5 meters, while maintaining effective electrical isolation between circuits.
3Productivity
If copper cabling is used for data communication, then data transmission is achieved, but transient and spurious voltages are communicated along the cable
Solution Approach 1:
The patent introduces an optical intermediary (light) between the transmitting and receiving circuits. The VCSEL converts electrical signals to optical signals, which then travel through an optical path to photodetectors that convert them back to electrical signals. This intermediary breaks the direct electrical connection, preventing transient voltages from propagating while maintaining data communication capability.
Solution Approach 2:
The invention replaces electrical signal transmission through copper cabling with optical signal transmission through an optical path. This substitution eliminates the conductive path that allows transient and spurious voltages to communicate between circuits, while preserving high-speed data communication capabilities.
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 effectively communicates high-speed digital data while providing robust electrical isolation, supporting data rates from 100 Megabits per second to 40 Gigabits per second, and is suitable for harsh vehicle environments, protecting against transient voltages and currents.
Implementation Method 1
employing a laser or light emitting diode for emitter
Implementation Method 2
an avalanche photo diode or PIN photodiode for detector
Data Source
AI summary
An apparatus and method for providing an isolated high-speed digital interface for communicating high-speed digital data within a vehicle. In architecture, the interface includes one or more input terminals and one or more output terminals. Each output terminal being associated with one of the one or more input terminals without any electrically conductive path existing between the output terminal and the input terminal, and instead the input terminal and the output terminal are coupled to one another by an optical coupling. The present invention can also be viewed as a method that can be broadly summarized by the following steps, providing at least one input terminal for receiving data and providing at least one output terminal. Wherein the output terminal is associated with the one input terminal without any electrically conductive path existing between the output terminal and the input terminal, are coupled to one another by an optical coupling.