Variable Optical Attenuator Control With Temperature Compensation
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Solution Overview
Problem
Conventional control devices face challenges in accurately adjusting the amount of attenuation by a variable optical attenuator due to high temperature dependence of signal intensity detection, requiring complex data preparation and arithmetic processing, and multiple loop control issues.
Innovation Solution
A control device with a temperature monitor and a controller that uses first and second functions to calculate a driving current value for the variable attenuator, correcting for temperature changes through a temperature correction factor, simplifying arithmetic processing and eliminating the need for feedback control loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensitivity characteristics corresponding to ambient temperature are used to correct driving current values, then attenuation accuracy is improved, but data preparation complexity and arithmetic processing load increase
Solution Approach 1:
The patent changes the parameter representation from storing complete sensitivity characteristics curves to storing only correction factors that adjust the driving current based on temperature deviations from a reference temperature. This reduces data preparation complexity while maintaining attenuation accuracy through the correction factor mechanism.
Solution Approach 2:
The patent extracts only the essential temperature compensation information (correction factors) from the complete sensitivity characteristics, separating the temperature-dependent correction element from the base driving current values. This extraction reduces the amount of data that needs to be prepared and stored while preserving the accuracy benefit.
2Measurement precision
If sensitivity characteristics corresponding to ambient temperature are used to correct driving current values, then attenuation accuracy is improved, but arithmetic processing load increases
Solution Approach 1:
The patent simplifies the arithmetic operation from complex curve-based sensitivity characteristic calculations to simple multiplication by temperature correction factors. This parameter transformation reduces the computational burden while maintaining the ability to compensate for temperature-induced attenuation errors.
3Measurement precision
If feedback control loops are implemented for multiple control purposes, then control precision is improved, but device complexity and processing load increase
Solution Approach 1:
The patent performs preliminary temperature compensation by calculating correction factors based on temperature deviations before the main control operation. This preliminary action eliminates the need for complex multiple feedback loops, as the temperature effect is corrected in advance through the driving current adjustment, simplifying the overall control architecture.
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
Accurately adjusts attenuation at varying temperatures with reduced data requirements and simplified processing, reducing the need for additional hardware and shortening preparation times, while addressing multiple loop control issues.
Implementation Method 1
a temperature monitor that measures a peripheral temperature around the variable attenuator
Implementation Method 2
a variable attenuator that attenuates input light
Data Source
AI summary
A control device has an attenuator, a monitor that measures a peripheral temperature around the attenuator, and a controller. The controller stores a first function approximating a relation between amounts of attenuation and driving current values at a standard temperature, and a second function for calculating a temperature correction factor that corrects a driving current value between the peripheral temperature and the standard temperature. The controller calculates, by the first function, a driving current value at the standard temperature, and calculates, by the second function, a temperature correction factor. Based on the driving current value at the standard temperature and calculated by the first function and the temperature correction factor calculated by the second function, the controller calculates a driving current value for obtaining the set amount of attenuation at the peripheral temperature. The controller controls driving of the attenuator based on the driving current value calculated.