Optical Transmission Device Spectrum Control via Wavelength Selective Switch
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Solution Overview
Problem
Existing optical communication systems face challenges in maintaining transmission quality due to variations in signal levels across different wavelengths, particularly when optical amplifiers are introduced, as they can alter the spectrum shape of wavelength multiplex signals in ways that are not adequately controlled by existing techniques.
Innovation Solution
An optical transmission device equipped with wavelength selecting, optical amplifying, measuring, setting, and control means that adjusts signal levels based on measured spectra and predetermined output spectrum settings to ensure optimal spectrum shape for transmission paths, using wavelength selective switches and optical amplifiers to manage signal levels and power across multiple wavelength bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If optical amplifiers are introduced to amplify wavelength multiplex signals, then signal level is improved, but spectrum shape is degraded due to wavelength-dependent amplification characteristics
Solution Approach 1:
The patent segments the wavelength multiplex signal into individual wavelength components using a wavelength selective switch, processes each wavelength separately by adjusting its signal level independently, and then recombines them. This segmentation allows the optical amplifier to amplify the overall signal while the wavelength selective switch compensates for wavelength-dependent variations, resolving the contradiction between signal level improvement and spectrum shape maintenance.
Solution Approach 2:
The patent applies local quality control by adjusting the signal level of each wavelength component individually rather than treating the entire spectrum uniformly. The wavelength selective switch enables selective attenuation or amplification for specific wavelengths, ensuring that each wavelength receives appropriate signal level adjustment tailored to its specific characteristics, thus maintaining the overall spectrum shape while improving signal level.
2Reliability
If signal level adjustment is performed for each wavelength, then transmission quality is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The wavelength selective switch serves multiple functions: it selects specific wavelengths from the multiplex signal, adjusts their signal levels independently, and recombines them into the output signal. This multi-functionality reduces the need for separate control mechanisms for each wavelength, thereby improving transmission quality while limiting the increase in device complexity.
Solution Approach 2:
The patent implements feedback control by measuring the signal level of each wavelength component and using this information to adjust the wavelength selective switch settings. The control unit continuously monitors the spectrum shape and signal levels, making real-time adjustments to maintain optimal transmission quality, thus achieving reliable performance with manageable complexity through automated feedback loops.
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 effectively controls the spectrum shape of wavelength multiplex signals, improving transmission quality by aligning signal levels with desired settings, even in the presence of wavelength-dependent optical amplifiers, and simplifies system configuration by eliminating the need for remote signal level information.
Implementation Method 1
an optical amplifying means for amplifying the wavelength multiplex signal
Implementation Method 2
a wavelength selecting means for selecting, as an optical signal to be output, an optical signal having a set wavelength from a wavelength multiplex signal that is input via an optical fiber
Data Source
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AI summary
[Problem] To provide an optical transmission device capable of controlling the spectrum shape of a wavelength multiplexed signal and improving the transmission quality. [Solution] A light transmission device is configured to include a wavelength selecting means 1, an optical amplifying means 2, a measuring means 3, a setting means 4, and a control means 5. The wavelength selecting means 1 has a means for selecting an optical signal, and a means for outputting a signal after adjusting the signal level. The optical amplifying means 2 amplifies the wavelength multiplexed signal having the adjusted signal level. The measuring means 3 measures the spectrum of the amplified wavelength multiplexed signal. The setting means 4 sets a spectrum shape, which serves as a reference of the wavelength multiplexed signal to be outputted to the transmission line, as output spectrum setting information. The control means 5 compares the measured spectrum with the output spectrum setting information and determines the attenuation amount when adjusting the signal level for each wavelength of the wavelength multiplexed signal in the wavelength selecting means 1. In addition, the wavelength selecting means 1 adjusts the signal level on the basis of the determined attenuation amount.