Low Baud Laser Centering for WDM Channel Overlap
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Solution Overview
Problem
In colorless photonic line systems, laser frequency errors lead to channel overlap, reducing performance or causing failure, especially in Nyquist-spaced channels, where existing methods for reducing laser error are costly and time-consuming, and require precise laser tuning.
Innovation Solution
Implementing a low baud start-up mode for laser centering control, which narrows the channel width during initial acquisition, allowing for tighter channel spacing and reducing the need for precise laser accuracy, thereby using lower-cost lasers and optimizing spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser frequency accuracy is improved to prevent channel overlap, then channel reliability is improved, but device cost and tuning time increase
Solution Approach 1:
The patent applies preliminary action by performing laser centering control during a low-baud start-up phase before full-speed operation. The modem initializes at a reduced baud rate (e.g., 1/4 or 1/8 of full rate) which narrows the spectral width, allowing laser frequency errors up to ±1 GHz without channel overlap. Once locked, the system transitions to full baud rate. This preliminary centering action eliminates the need for high-precision lasers throughout operation.
2Productivity
If channel spacing is reduced to improve spectral efficiency, then spectral efficiency is improved, but channel overlap increases due to laser frequency errors
Solution Approach 1:
The system performs preliminary laser centering at low baud rate before enabling tight channel spacing. During initialization, the narrowed spectral width at low baud prevents overlap even with relaxed laser precision. After centering is achieved, the system can safely operate with Nyquist-spaced or tighter channels at full baud rate without overlap, because the laser frequencies are already centered.
Solution Approach 2:
The patent applies dynamics by making the baud rate variable during different operational phases. The system dynamically adjusts baud rate: low during start-up for centering control, and high during normal operation for maximum spectral efficiency. This dynamic adjustment allows tight channel spacing without permanent risk of overlap.
3Reliability
If high-precision lasers are used to maintain channel separation, then channel reliability is improved, but device cost increases
Solution Approach 1:
The patent performs preliminary laser centering control during low-baud initialization, which maintains channel separation without requiring high-precision lasers. The low spectral width at reduced baud rate provides a margin that accommodates ±1 GHz laser errors. This preliminary action enables the use of lower-cost lasers while maintaining reliable channel separation throughout operation.
Data Source
AI summary
Aspects of the subject disclosure may include, for example, arranging a signal into a wavelength division multiplexing (WDM) spectral slot, wherein the signal has a first spectral width, communicating with a receiver using the signal, determining one or more network characteristics based on the communicating, adjusting a center wavelength of the signal in accordance with the one or more network characteristics, modifying the signal such that the signal has a second spectral width, resulting in a modified signal, wherein the second spectral width is larger than the first spectral width, and causing the modified signal to carry traffic to the receiver. Other embodiments are disclosed.