Dummy Optical Signal Generation Using Comb Filters for Low-Cost WDM
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Solution Overview
Problem
The high costs and inefficiencies associated with enabling all wavelengths at the initial stage in dummy light technology for optical fiber communications, due to the need for numerous optical transponder units, are exacerbated by nonlinear effects such as stimulated Raman scattering, which decrease optical power.
Innovation Solution
A cascading system is employed, utilizing a multi-longitudinal mode laser and comb optical bandpass filter to generate dummy optical signals, which are then multiplexed by a wavelength division multiplexing device, incorporating bandpass filters to ensure flatness and peak power, and optionally using circulators and couplers for resonant cavities to equalize gain and improve flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all wavelengths are enabled at the initial stage using traditional dummy light technology, then the stimulated Raman scattering effect is mitigated, but the cost increases due to the need for numerous optical transponder units
Solution Approach 1:
The patent segments the dummy light generation function across multiple independent apparatuses, each generating dummy light at different wavelength ranges. This segmentation allows the system to cover all wavelengths without requiring every wavelength to be enabled simultaneously in a single apparatus, thus reducing the number of optical transponder units needed while still mitigating stimulated Raman scattering effects.
Solution Approach 2:
The patent introduces a new dimension by using multiple apparatuses operating at different wavelength ranges instead of relying on a single apparatus to handle all wavelengths. This dimensional approach to wavelength management enables cost reduction while maintaining the reliability of Raman scattering mitigation.
2Adaptability or versatility
If multiple optical transponder units are configured at the initial stage, then dummy light can be generated for all wavelengths, but the cost increases significantly
Solution Approach 1:
The patent divides the dummy light generation task into segments handled by different apparatuses, each responsible for specific wavelength ranges. This segmentation enables the system to achieve full wavelength coverage without requiring all transponder units to be configured simultaneously, thereby reducing costs while maintaining adaptability.
Solution Approach 2:
The patent merges the outputs of multiple dummy light generating apparatuses through multiplexing to create a comprehensive dummy light spectrum. This combining approach achieves the versatility of full wavelength coverage at a reduced cost compared to using a single apparatus with all transponder units configured.
3Productivity
If high-power multi-wavelength optical signals are coupled into one optical fiber, then wavelength division multiplexing is achieved, but nonlinear effects increase limiting transmission performance
Solution Approach 1:
The patent introduces dummy light as an intermediary element that fills the spectral gaps between signal wavelengths. This intermediary dummy light reduces the peak power density at signal wavelengths, thereby reducing nonlinear effects in the optical fiber while maintaining the high productivity of wavelength division multiplexing.
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 approach reduces costs by minimizing the need for initial configuration of multiple optical transponders and effectively mitigates nonlinear effects by reducing relative intensity noise, thereby enhancing signal transmission reliability and scalability.
Implementation Method 1
a multi-longitudinal mode laser (201) configured to provide a light source signal
Implementation Method 2
a comb optical bandpass filter (202) configured to output a dummy optical signal from the light source signal provided by the multi-longitudinal mode laser (201)
Implementation Method 3
The at least one multiplexing apparatus multiplexes dummy optical signals generated by the plurality of apparatuses for generating dummy optical signals
Implementation Method 4
optionally using circulators and couplers for resonant cavities to equalize gain and improve flatness
Data Source
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Figure 3
Figure 4~5
AI summary
Embodiments of this application disclose an apparatus for generating a dummy optical signal, to reduce costs of generating a dummy optical signal. The apparatus specifically includes: a multi-longitudinal mode laser and a comb optical bandpass filter, where the multi-longitudinal mode laser is connected to the comb optical bandpass filter, and the multi-longitudinal mode laser is configured to provide a light source signal. A light source signal provided by the multi-longitudinal mode laser outputs a dummy optical signal through the comb optical bandpass filter, and the dummy optical signal is an optical signal that does not include service information. The multi-longitudinal mode laser and the comb optical bandpass filter have low costs, so that costs of generating the dummy optical signal are reduced.