Optical Wavelength Selecting Filter Module with Temperature Compensation
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Solution Overview
Problem
The existing optical wavelength-selective filter modules in optical access systems require complex mechanisms to measure and compensate for wavelength shifts caused by temperature variations, leading to increased complexity and costs, especially in ONU devices used by individual communication service users.
Innovation Solution
An optical wavelength-selective filter module that includes an optical filter whose orientation can be changed, a frequency information acquiring unit, a temperature information acquiring unit, and an actuator, which determines and adjusts the filter's orientation based on pre-established relationship information to maintain optimal transmittance regardless of temperature changes, allowing for compensation of wavelength shifts without the need for light intensity measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dielectric multilayer film filter is used for wavelength selection, then optical wavelength selectivity is achieved, but wavelength shift occurs due to temperature variations
Solution Approach 1:
The patent changes the physical parameter of the optical filter by adjusting its inclination angle to compensate for wavelength shifts. The control unit calculates the required angle adjustment based on temperature information and relationship information, then the actuator rotates the filter to the new angle, thereby compensating for the wavelength shift caused by temperature variations.
Solution Approach 2:
The patent implements a feedback control mechanism where temperature information is continuously acquired, processed to determine the appropriate filter angle, and then applied through the actuator. The control unit uses relationship information (pre-stored calibration data) to map temperature changes to the required angular adjustment, creating a closed-loop feedback system that maintains accurate wavelength selection despite temperature variations.
2Reliability
If temperature compensation mechanisms are added to compensate for wavelength shifts, then wavelength stability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex optical measurement and adjustment mechanisms with a simpler system based on temperature sensing and direct angular control. Instead of using optical branching devices, detectors, and iterative optimization mechanisms, the system uses temperature information combined with pre-stored relationship information to directly calculate and apply the required angle adjustment, significantly simplifying the overall device architecture.
Solution Approach 2:
The patent performs preliminary action by pre-storing relationship information that maps temperature values to optimal filter angles. This calibration data is stored in advance, allowing the control unit to quickly determine the required angle adjustment without real-time complex calculations or iterative optimization processes, thereby simplifying the runtime operation and reducing device complexity.
3Measurement precision
If light intensity measurement mechanisms are added to track wavelength variations, then wavelength compensation accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the need for light intensity measurement mechanisms by using an alternative approach based on temperature sensing and pre-stored relationship information. The system takes out the optical branching device, detector, and associated control mechanisms, replacing them with a temperature-based control system that achieves wavelength compensation without requiring light intensity measurements, thereby reducing manufacturing costs.
4Manufacturing precision
If optical filters are made highly selective with narrow bandwidth, then wavelength selection capability is improved, but sensitivity to temperature variations increases
Solution Approach 1:
The patent makes the optical filter dynamic by enabling rotation to adjust its inclination angle. This dynamic capability allows the filter to adapt to temperature variations by changing its angle, thereby compensating for the increased sensitivity to temperature that comes with narrow bandwidth filtering. The actuator enables continuous or discrete angle adjustments to maintain optimal performance across different temperature conditions.
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 effective compensation of transmission wavelength shifts due to temperature variations while simplifying the apparatus, reducing complexity and costs, and allowing for mass production of ONU devices with wavelength compensation capabilities.
Implementation Method 1
an optical filter of which an orientation can be changed... an optical filter which transmits light of a frequency indicated by the frequency information at transmittance that is equal to or higher than reference transmittance
Implementation Method 2
a dielectric multilayer film filter has a characteristic in that an optical wavelength to be transmitted shifts according to surrounding environment temperature. This is attributable to thermal expansion of the dielectric multilayer film
Data Source
AI summary
An optical wavelength selecting filter-module into which light is incident from a prescribed direction determined in advance, the optical wavelength-selective filter module including: an optical filter of which an orientation can be changed; a frequency information acquiring unit which acquires frequency information that is information indicating a frequency of light to be transmitted through the optical filter; a temperature information acquiring unit which acquires temperature information that indicates a temperature of the optical filter; a determining unit which determines an orientation of the optical filter based on relationship information that is information associating, for each prescribed frequency, the temperature and an orientation of the optical filter at which light of the frequency is transmitted through the optical filter at transmittance equal to or higher than prescribed transmittance at the temperature, a temperature indicated by the temperature information, and a frequency indicated by the frequency information; and an actuator which points the optical filter in an orientation having been determined by the determining unit.