Wavelength Selective Switch Passband Expansion via Deflector Segmentation
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Solution Overview
Problem
Current wavelength selective switches (WSS) in optical communication networks face challenges in maximizing channel passband while minimizing crosstalk, especially when signal baud rates are set close to channel spacing, leading to potential loss of signal information.
Innovation Solution
The method involves spatially separating adjacent wavelength channels onto an optical deflector array with a two-dimensional lattice of deflection elements, where specific phase shift profiles are controlled to deflect channel portions to different output ports, allowing for a wider passband by including additional deflection elements from adjacent channel regions, thereby increasing the passband width but potentially increasing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the passband of the channel is maximized to improve spectral efficiency, then spectral efficiency is improved, but crosstalk from adjacent channels increases
Solution Approach 1:
The patent segments the optical deflector array into multiple regions, each responsible for different wavelength channels. By dividing the array into distinct regions with dedicated deflection elements for each channel, the system can independently control each channel's passband while maintaining separation from adjacent channels, thus resolving the contradiction between maximizing passband and minimizing crosstalk
Solution Approach 2:
The patent applies local quality by assigning specific deflection elements to specific wavelength channels in a localized manner. Each region of the optical deflector array is optimized for its designated channel, with deflection elements configured to handle only that channel's wavelengths. This localized assignment allows each channel to have maximized passband within its region without interfering with adjacent channels in other regions
2Productivity
If signal baud rate is set close to channel spacing to improve spectral efficiency, then spectral efficiency is improved, but signal information loss occurs
Solution Approach 1:
The patent segments the wavelength spectrum into distinct channels with dedicated deflection regions. By assigning separate regions for each wavelength channel, the system ensures that even when baud rate is close to channel spacing, each channel's signal is confined to its designated region and does not overlap with adjacent channels, preventing signal information loss while maintaining high spectral efficiency
Solution Approach 2:
The optical deflector array acts as an intermediary between the incoming optical signal and the output. It mediates the signal by selectively deflecting specific wavelength portions to specific output ports based on their spatial separation, ensuring that signals with baud rates close to channel spacing remain distinct and do not interfere with each other
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 enhances the passband width of wavelength selective switches, improving spectral efficiency while managing crosstalk, which can be further mitigated in downstream Select WSS configurations.
Implementation Method 1
controlling phase shift profiles of the deflection elements in the first and second areas of the optical deflector array
Implementation Method 2
modifying deflection elements in a first area of the optical deflector array to deflect a first wavelength channel portion of the first wavelength channel to a first output port
Data Source
AI summary
Methods and apparatus are provided that configure a wider passband for one or more channels of a wavelength selective switch (WSS). When a wider passband route WSS and a normal width passband select switch are used in combination, crosstalk that may be introduced by the wider passband route WSS can be mitigated. The wider passband WSS can provide a passband that allows a maximum bandwidth of signal to pass on a given channel and avoid signal being attenuated at the channel edges, especially when channels have a reduced channel spacing, such as with 50 GHz spacing.