Shared-Pump Wavelength Conversion for Phase Noise Cancellation
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Solution Overview
Problem
The accumulation of phase noise during wavelength conversion in optical transmission nodes, particularly in systems with high symbol rates and large wavelength dispersion, leads to signal distortion due to the addition of phase noise from pump light sources, which is equivalent to using lasers with wide linewidths, and the variation in wavelength accuracy of pump sources causes signal wavelength shifts.
Innovation Solution
An optical transmission node design that uses a common pump light source for both wavelength converters, with a coupler distributing light to these converters, and adjusts path lengths to ensure that phase noise and frequency offsets cancel each other out, thereby suppressing noise accumulation and maintaining signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wavelength conversion is performed using separate pump light sources for each converter, then wavelength conversion functionality is achieved, but phase noise accumulates and signal quality deteriorates
Solution Approach 1:
The patent merges multiple pump light sources into a single shared pump source that serves multiple wavelength converters. This consolidation ensures that phase noise is introduced at a single point in the system rather than accumulating from multiple independent sources, thereby maintaining signal quality while enabling wavelength conversion functionality.
Solution Approach 2:
The single pump light source is designed to serve multiple wavelength converters simultaneously, providing multi-functionality. This universal pump source can support conversions between different wavelength bands (e.g., C-band to L-band and vice versa) without requiring separate dedicated pump sources for each converter, thus reducing phase noise accumulation while maintaining conversion capabilities.
2Adaptability or versatility
If multiple wavelength converters are deployed in optical transmission nodes, then transmission flexibility is improved, but phase noise accumulation increases
Solution Approach 1:
The patent implements a universal pump source architecture where a single pump light source supports multiple wavelength converters for different wavelength band conversions. This enables the system to maintain transmission flexibility and adaptability across multiple converters while preventing phase noise accumulation that would occur with separate pump sources.
Solution Approach 2:
Instead of using multiple independent pump sources, the system uses one master pump source that is effectively 'copied' or distributed to multiple converters through optical coupling. This approach maintains the functional capability of multiple converters while ensuring that the phase noise characteristics are consistent and non-accumulative across all conversion paths.
3Reliability
If lasers with narrow spectral linewidth are used to meet high symbol rate requirements, then signal transmission quality is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent uses a single shared pump light source as an intermediary that serves multiple wavelength converters. This intermediary approach allows the system to achieve narrow effective linewidth and high signal transmission quality through the common phase reference provided by the single pump, without requiring each converter to use separately manufactured narrow-linewidth lasers, thereby reducing manufacturing difficulty and cost.
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 configuration effectively suppresses phase noise accumulation and maintains signal quality by ensuring that the phase noise and frequency offsets are minimized, allowing operation within the margin of the laser linewidth and reducing signal distortion.
Implementation Method 1
a coupler configured to distribute light emitted from the pump light source to the first wavelength converter and the second wavelength converter
Implementation Method 2
a first wavelength converter configured to convert an optical signal in a first wavelength band into an optical signal in a second wavelength band; a second wavelength converter configured to reconvert the optical signal in the second wavelength band to the optical signal in the first wavelength band
Data Source
AI summary
An optical transmission node includes a first wavelength converter configured to convert an optical signal in a first wavelength band into an optical signal in a second wavelength band, a second wavelength converter configured to reconvert the optical signal in the second wavelength band to the optical signal in the first wavelength band, a pump light source used in common for the first wavelength converter and the second wavelength converter, and a coupler configured to distribute light emitted from the pump light source to the first wavelength converter and the second wavelength converter.