Pilot Tone Removal in Digital Wavelength Converters
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Solution Overview
Problem
Coherent waveform conversion systems fail to properly convert pilot tones, leading to misidentification of wavelengths in optical data signals, which results in incorrect processing of the output optical signal.
Innovation Solution
A method and apparatus for removing pilot tones from optical signals by calculating a pilot tone cancellation factor based on the pilot tone frequency, modulation depth, and phase, and multiplying compensated waveforms with this factor to eliminate the pilot tone, allowing for accurate wavelength identification and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If coherent waveform conversion is used for wavelength conversion, then processing complexity is reduced and wavelength conversion is simplified, but the pilot tone fails to properly identify the converted wavelength
Solution Approach 1:
The patent extracts and removes the pilot tone component from the converted waveform separately, then adds a new pilot tone with the correct wavelength identification. This separation allows the main waveform to be converted simply while the pilot tone is independently managed to ensure accurate wavelength identification.
Solution Approach 2:
The patent segments the waveform processing into distinct steps: removing the original pilot tone, converting the data signal, and adding a new pilot tone. This segmentation resolves the contradiction by handling the pilot tone separately from the main signal conversion.
2Measurement precision
If traditional wavelength conversion methods are used, then the pilot tone can be properly converted to identify the new wavelength, but extensive processing is required to extract data and convert waveforms
Solution Approach 1:
The patent uses an intermediary approach by introducing a digital waveform converter that processes the electrical signal between optical-to-electrical and electrical-to-optical conversion. This intermediary step enables simple pilot tone removal and addition while maintaining wavelength identification accuracy.
3Quantity of substance
If pilot tones are modulated to carry additional information, then more data can be transmitted, but the pilot tone removal process becomes more complex
Solution Approach 1:
The patent employs feedback mechanisms in the digital waveform converter to detect and preserve modulation information on the pilot tone while removing the wavelength identification component. This allows retention of additional information while simplifying the removal process.
Data Source
AI summary
The present applies to digital wavelength converters that convert, independently of the format in which optical data may be encoded, an input waveform at a first wavelength to an output waveform at a second wavelength. When operating in an environment where an input waveform has a pilot tone associated thereto, the method and system of the present disclosure allows for the removal of the pilot tone from the input waveform, and also allows for the addition of another pilot to the output waveform.