Optical Power Control via Variation Detection
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Solution Overview
Problem
In wavelength-division-multiplexing optical transmission systems, existing technologies face challenges in timely and cost-effective power control of optical signals due to changes in the number of wavelengths or transmission loss, leading to potential deterioration in transmission quality and high costs associated with complex circuitry.
Innovation Solution
An optical transmission apparatus and method that includes a variation-detecting unit to assess the speed of power changes in wavelength-division-multiplexed signals, an optical amplifying unit for fixed amplification, a variable optical attenuator, and a controlling unit to adjust attenuation based on detected variations, enabling timely and appropriate power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wavelength-division-multiplexed number detecting circuit is provided to monitor the number of wavelengths, then the power control accuracy is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts only the essential information needed for power control (total optical power level) from the wavelength-division-multiplexed signal, rather than detecting each wavelength component separately. This is achieved by using a photodetector to measure the integrated power of all wavelengths combined, eliminating the need for complex wavelength-by-wavelength detection circuits while maintaining sufficient control accuracy.
Solution Approach 2:
The patent employs a universal power detection mechanism that handles both wavelength count changes and transmission loss variations through a single detection channel. The photodetector-based power level detection circuit serves multiple functions: monitoring total power, detecting power variations regardless of cause, and triggering appropriate control responses, thereby replacing multiple specialized detection circuits.
2Device complexity
If supervisory signals are used to transmit wavelength count information, then the device complexity is reduced, but the response time increases significantly
Solution Approach 1:
The patent implements continuous real-time monitoring of the optical power level using the photodetector, which continuously converts optical power variations into electrical signals. This continuous detection mechanism eliminates the intermittent nature of supervisory signal-based information transmission, ensuring that power variations are detected and responded to immediately without waiting for scheduled supervisory signal exchanges between network elements.
Solution Approach 2:
The patent establishes a direct feedback loop where the photodetector continuously monitors the optical power level and immediately feeds this information to the control unit. When power variations exceed a threshold, the control unit rapidly adjusts the variable optical attenuator to restore the desired power level. This closed-loop feedback mechanism provides immediate response to power variations, eliminating the time delay inherent in supervisory signal-based control.
3Reliability
If automatic gain control is applied to maintain constant average power, then the transmission quality is improved, but the ability to distinguish between wavelength count changes and transmission loss variations is reduced
Solution Approach 1:
The patent implements dynamic control that adapts its response based on the detected power variation characteristics. The control unit continuously monitors the power level and dynamically adjusts the variable optical attenuator settings in real-time. This dynamic approach allows the system to maintain constant average power while preserving the ability to detect and respond to different types of variations (wavelength count changes versus transmission loss) through their distinct temporal and magnitude patterns.
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 allows for timely determination and correction of power variations caused by changes in wavelengths or transmission loss, maintaining constant output per channel without significant delay or added cost, thereby enhancing transmission quality and reliability.
Implementation Method 1
an optical amplifying unit which amplifies the wavelength-division-multiplexed optical signal at a fixed amount of amplification
Implementation Method 2
a variable optical attenuating unit which variably attenuates the wavelength-division-multiplexed optical signal
Data Source
AI summary
An optical transmission apparatus for amplifying and relaying a wavelength-division-multiplexed optical signal includes (1) a variation-detecting unit which detects varying speed of input power of the wavelength-division-multiplexed optical signal and compares the varying speed with a set value, (2) an optical amplifying unit which amplifies the wavelength-division-multiplexed optical signal at a fixed amount of amplification, (3) a variable optical attenuating unit which variably attenuates the wavelength-division-multiplexed optical signal, (4) and a controlling unit which controls attenuation amount of the variable optical attenuating unit in accordance with the varying speed.