Dummy Light Spectrum Shaping for WDM Idle-Band Identification
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Solution Overview
Problem
In optical wavelength division multiplexing (WDM) systems, distinguishing between dummy light and service light is challenging due to the use of dummy light to maintain system stability, especially when the optical bandwidth is not fully occupied, leading to power jitter issues from stimulated Raman scattering (SRS) effects.
Innovation Solution
A method involving a light emitting apparatus that generates multi-wavelength dummy light, shapes its spectrum to create distinct spectral features different from service light, and multiplexes it with service light for transmission, allowing a light receiving apparatus to distinguish between the two based on these spectral differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy light is used to occupy idle bands to ensure system stability, then system stability is improved, but the ability to distinguish between dummy light and service light deteriorates
Solution Approach 1:
The patent applies spectrum shaping to alter the spectral characteristics of dummy light, creating distinct spectral features (such as periodic variations or dip features) that differentiate it from service light. This is analogous to color changes, where the 'color' or spectral composition of the light is modified to enable identification while maintaining its functional role as dummy light for system stability.
2Difficulty of detecting and measuring
If spectrum shaping is applied to create distinct spectral features, then the ability to distinguish dummy light from service light is improved, but device complexity increases
Solution Approach 1:
The patent employs spectrum shaping techniques that modify spectral parameters (such as intensity distribution across wavelengths, periodicity, or dip positions) of dummy light to create identifiable features. By changing these spectral parameters rather than fundamentally altering the light generation mechanism, the solution achieves distinguishability while controlling the increase in device complexity.
3Reliability
If dummy light is used to fill idle bands, then power jitter from SRS effect is reduced, but additional modulation on dummy light is avoided to simplify implementation
Solution Approach 1:
The patent applies spectrum shaping to dummy light in advance, before it is multiplexed with service light for transmission. This preliminary modification of spectral characteristics ensures that the dummy light will be distinguishable at the receiving end without requiring additional real-time modulation or complex processing during transmission, thereby simplifying the overall implementation while maintaining system stability.
Data Source
AI summary
A dummy light transmission method, a dummy light identification method, and a related device. A light emitting apparatus performs spectrum shaping on first multi-wavelength dummy light generated by a dummy light source, to obtain second multi-wavelength dummy light, so that a spectral feature of the second multi-wavelength dummy light is different from a spectral feature of service light. The light emitting apparatus selects target dummy light from the second multi-wavelength dummy light to fill an idle band. A light receiving apparatus receives the service light and the target dummy light from the light emitting apparatus. Because the target dummy light and the service light have different spectral features, the light receiving apparatus can effectively distinguish the service light from the target dummy light through spectrum detection and spectrum analysis.