Wavelength Control in Light Source Devices via Feedback
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Solution Overview
Problem
Existing light source devices for wavelength division multiplexing (WDM) systems face high power consumption due to the need for thermoelectric coolers (TECs) to maintain accurate wavelength control, as light source wavelengths shift with temperature changes, leading to inefficiencies in power management.
Innovation Solution
A light source device incorporating photodetectors, optical bandpass filters, and a temperature adjustment unit controlled by a processor to maintain wavelengths within a specified grid, reducing the need for continuous TEC operation by monitoring and adjusting temperature based on detected power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermoelectric cooler (TEC) is used to stabilize the temperature of light sources, then wavelength control accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements a feedback control system where photodetectors monitor the actual wavelengths of light sources, and the controller adjusts TEC operation based on detected wavelength deviations from target values. This closed-loop feedback enables accurate wavelength control while minimizing TEC operation to only when necessary, reducing power consumption compared to continuous TEC operation.
Solution Approach 2:
The patent applies partial action by operating the TEC only partially - specifically, only when wavelength deviations exceed predetermined thresholds. The controller compares detected wavelengths with target wavelengths and activates the TEC only when correction is needed, rather than maintaining continuous operation. This selective activation maintains wavelength accuracy while significantly reducing overall power consumption.
2Stability of the object's composition
If the TEC operates continuously to maintain wavelength stability, then wavelength control accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic action by having the controller periodically monitor wavelengths using photodetectors and activate the TEC only during periods when wavelength deviations are detected. Instead of continuous operation, the system performs intermittent temperature adjustments based on real-time wavelength monitoring, maintaining stability while reducing power consumption through periodic rather than continuous TEC activation.
Solution Approach 2:
The system performs self-service through automatic wavelength monitoring and self-correction. The photodetectors continuously monitor wavelength deviations, and the controller automatically activates the TEC when corrections are needed without external intervention. This autonomous operation maintains wavelength stability while optimizing power consumption by activating the TEC only when the system itself detects the need for correction.
3Measurement precision
If the width of passbands of optical bandpass filters is reduced to be less than wavelength spacing, then wavelength selectivity is improved, but transmission efficiency decreases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the relationship between filter passband widths and wavelength spacing. The system is designed with passband widths specifically set to be less than the wavelength spacing between adjacent WDM channels, creating an optimal parameter configuration that achieves high wavelength selectivity for accurate wavelength detection while managing transmission efficiency through the specific geometric relationship between passband width and channel spacing.
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 solution enables accurate wavelength control while significantly reducing power consumption by only activating the TEC when necessary, thus optimizing energy use in WDM systems.
Implementation Method 1
a plurality of photodetectors that detect output powers of the plurality of light sources
Implementation Method 2
a plurality of optical bandpass filters that are provided between the plurality of light sources and the plurality of photodetectors
Implementation Method 3
optical bandpass filters that are provided between the plurality of light sources and the plurality of photodetectors
Implementation Method 4
a temperature adjustment unit that adjusts a temperature of an area around the plurality of light sources
Implementation Method 5
temperature adjustment unit that adjusts a temperature of an area around the plurality of light sources
Data Source
AI summary
A light source device includes: a plurality of light sources that generate rays of light with different wavelengths corresponding to a plurality of target wavelengths located on a designated wavelength grid; a plurality of photodetectors that detect output powers of the plurality of light sources; a plurality of optical bandpass filters that are provided between the plurality of light sources and the plurality of photodetectors; a temperature adjustment unit that adjusts a temperature of an area around the plurality of light sources; and a processor that controls the temperature adjustment unit based on output signals of the plurality of photodetectors. Widths of passbands of the optical bandpass filters are less than a wavelength spacing in the wavelength grid.