WDM Multiplexing with Passive Filters for 400G Migration
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Solution Overview
Problem
Current optical transmission networks face challenges in efficiently supporting higher data rates such as 400 Gbit/s and 1 Tbit/s over existing fiber optic links with fixed wavelength grids, leading to spectral fragmentation and increased costs due to the need for complex and expensive wavelength-selective switches.
Innovation Solution
The method involves combining optical signals with different wavelength grids, using passive multiplex filters and tunable edge filters to create a wavelength-division multiplex signal, allowing for flexible channel spacing and power balancing, enabling the coexistence of multiple data rates within the same network without requiring expensive flexgrid WSS components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive WDM multiplexers with fixed channel widths are used, then channel separation is achieved, but spectral fragmentation occurs and insertion loss increases in attenuation bands
Solution Approach 1:
The patent applies dynamics by making the channel bandwidth configurable rather than fixed. The WSS (wavelength-selective switch) allows dynamic adjustment of channel widths to match different data rates (10 Gbit/s, 40 Gbit/s, 100 Gbit/s, 400 Gbit/s), enabling the system to adapt to varying traffic demands without spectral fragmentation caused by rigid fixed-width channels
Solution Approach 2:
The patent changes the parameter of channel bandwidth from a fixed value to a variable parameter. By allowing channel widths to be adjusted according to the required data rate, the system optimizes spectral utilization and avoids the insertion loss problems associated with fixed-width channels that create attenuation bands
2Productivity
If overlay networks are built to achieve 400 Gbit/s data rates, then higher data rates are transmitted, but network costs increase significantly
Solution Approach 1:
The patent applies universality by designing a single WSS-based platform that can handle multiple data rates (10, 40, 100, and 400 Gbit/s) using the same physical infrastructure. The configurable channel bandwidth allows the system to serve different service requirements without building separate overlay networks, thereby reducing overall network costs while maintaining high data rate capability
3Stability of the object's composition
If fixed 50 GHz channel grids are used for 400 Gbit/s transmission, then channel spacing is maintained, but spectral bandwidth is insufficient
Solution Approach 1:
The patent applies dynamics by enabling the channel grid spacing to be dynamically adjusted. The WSS allows channel bandwidths to be configured based on data rate requirements, so that 400 Gbit/s channels can utilize wider bandwidths when needed while maintaining compatibility with existing 50 GHz grids for lower data rates, thus providing both stability and adaptability
Data Source
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AI summary
To provide a simple migration path from current optical transmission networks to higher data rates of, for example, 400 Gbit/s or 1 Tbit/s, the invention proposes combining different fixed wavelength grids in a multiplexed signal within a WDM-based transparent optical transmission system. For this purpose, several passive multiplexing filters are used in the add/drop path of a ROADM to efficiently mix different data rates in an optical data transmission network with an optically transparent network approach using simple and cost-effective components. In particular, the invention provides a method for multiplexing and/or demultiplexing, as well as an optical network element and an optical transmission network.