Spatial Light Modulator Pixel Pitch and Transmissivity for WDM Spectrum Smoothing
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Solution Overview
Problem
Existing spatial light modulators in WDM systems suffer from transmission penalties due to spectral transmission dips caused by inter-pixel gaps, leading to distorted signals and inefficient bandwidth allocation.
Innovation Solution
The apparatus reduces transmission drops by adjusting the pitch and contour of modulating components, with pixel pitch set to be less than or equal to the beam size and using parallelogram or curvilinear shapes for the modulating components to minimize the localization of inter-pixel gaps, thereby smoothing the modulated transmission spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pixel pitch is increased to match system channel spacing, then device complexity is reduced and ease of operation is improved, but spectral transmission dips occur causing signal distortion and transmission penalties
Solution Approach 1:
The patent applies local quality by making adjacent pixels have different transmissivity values. Specifically, pixels are assigned alternating transmissivity patterns (e.g., high-low-high-low or random variations) to locally compensate for the transmission dips caused by inter-pixel gaps. This local variation in transmissivity counteracts the periodic spectral dips without requiring changes to the overall pixel pitch or spacing.
2Reliability
If inter-pixel gaps are reduced to minimize transmission dips, then signal transmission quality is improved, but manufacturing precision requirements increase and device complexity increases
Solution Approach 1:
The patent changes the transmissivity parameter of pixels to compensate for inter-pixel gap effects. By adjusting the transmissivity values of adjacent pixels (creating alternating high-low patterns or random variations), the system compensates for transmission dips without physically reducing the pixel gaps. This parameter change approach maintains manufacturing feasibility while achieving smooth transmission spectra.
3Reliability
If pixel pitch is decreased to be less than beam size, then spectral transmission dips are reduced, but device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent implements local quality by assigning different transmissivity values to adjacent pixels within the same pixel array. This allows the system to achieve smooth transmission spectra through software-controlled transmissivity modulation rather than physical pixel pitch reduction, thereby maintaining simpler device architecture while achieving the desired transmission characteristics.
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 significantly reduces transmission drops and penalties, enabling more flexible and efficient optical bandwidth allocation while maintaining acceptable transmissivity levels.
Implementation Method 1
a spatial dispersion mechanism for spatially dispersing an optical signal, the spatially dispersed optical signal including a plurality of frequency components
Data Source
AI summary
The invention includes an apparatus for modulating an optical signal. The apparatus includes a spatial dispersion mechanism and a modulating mechanism. The spatial dispersion mechanism spatially disperses the optical signal. The spatially dispersed optical signal has a plurality of frequency components where each frequency component has an associated beam size. The modulating mechanism includes an array of modulating components where each modulating component has a pitch. The pitch of each modulating component is substantially equal to or less than the beam size of each frequency component.