LCOS Device Rectangular Pixels WSS Complexity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The increasing demand for higher performance wavelength selective switches (WSS) in optical networks requires a greater number of pixels in LCOS devices, which increases complexity, power consumption, and manufacturing costs, while also limiting opto-mechanical design space.

Innovation Solution

A liquid crystal on silicon (LCOS) device with a two-dimensional array of pixels, where the pixel pitch is greater in one dimension than the other, allowing for optimized pixel size and number determination based on specific WSS requirements, including the number of optical ports and switching angles, to enhance switching capabilities without increasing overall complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of pixels in the LCOS device is increased to achieve higher performance WSS, then the switching capability and fiber capacity are improved, but the device complexity, power consumption, and manufacturing cost increase

Engineering Contradiction:
Improveswitching capabilityVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by using rectangular pixels with different dimensions in the wavelength axis versus the switching axis. This asymmetric pixel design allows the device to achieve high performance with optimized pixel counts in each axis, reducing the total number of pixels needed compared to a symmetric square pixel design, thereby lowering complexity while maintaining productivity

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the number of pixels in the LCOS device is increased to support more optical fibers, then the port switching capability is improved, but the power consumption increases

Engineering Contradiction:
Improveport switching capabilityVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by having different pixel dimensions in different axes - larger pixels in the switching axis to support more optical fibers with fewer pixels, and appropriate pixel size in the wavelength axis. This localized optimization reduces the total pixel count needed for high port switching capability, thereby reducing overall power consumption while maintaining the required productivity

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the number of pixels in the LCOS device is increased to increase fiber capacity, then the wavelength axis granularity is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvewavelength axis granularityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry by using rectangular pixels with optimized dimensions where the wavelength axis has sufficient resolution for improved granularity, while the switching axis uses larger pixels to reduce total count. This asymmetric design achieves the required measurement precision in the wavelength axis without proportionally increasing the total number of pixels, thereby controlling manufacturing costs

Inventive Principle:
Principle #4Asymmetry

4Productivity

If the number of pixels in the LCOS device is increased to handle wider frequency ranges, then the fiber capacity is improved, but the opto-mechanical design space is limited

Engineering Contradiction:
Improvefiber capacityVSAvoidopto-mechanical design space
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by optimizing pixel dimensions locally in each axis - using larger pixels in the switching axis to reduce the number of pixels needed for handling multiple fibers, and appropriate pixel sizing in the wavelength axis for the required frequency range. This localized optimization reduces the total pixel count, thereby reducing the required opto-mechanical design space while maintaining high fiber capacity

Inventive Principle:
Principle #3Local quality

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 enables efficient switching of multiple optical channels with reduced power consumption and manufacturing costs, while maintaining optimal opto-mechanical design, by tailoring pixel shape and number to specific WSS applications.

Implementation Method 1

The liquid crystal layer is disposed between the upper and lower electrodes and is configured to be driveable into a plurality of electrical states by drive signals provided to the pixels of the lower electrode

Methodology Applied
Scientific EffectLiquid crystal phase modulation: Liquid Crystals

Implementation Method 2

The liquid crystal layer is configured to be driveable into a plurality of electrical states by drive signals provided to the pixels of the lower electrode

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentEP4130863B1WSS utilizing LCOS arrays comprising rectangular pixels
Publication Date: 2024.08.28 II VI DELAWARE INC
  • EP4130863B1 patent drawingFigure 1
  • EP4130863B1 patent drawingFigure 2
  • EP4130863B1 patent drawingFigure 3

AI summary

A liquid crystal on silicon (LCOS) device includes a silicon substrate and a pair of electrodes including an upper and a lower electrode. The lower electrode is mounted to the silicon substrate and includes a two dimensional array of pixels extending in both a first and second dimension. LCOS device also includes a liquid crystal layer disposed between the upper and lower electrodes and configured to be driveable into a plurality of electrical states by drive signals provided to the pixels of the lower electrode. The pixels are rectangular in profile having longer sides in the first dimension than in the second dimension. Further, the two dimensional array includes a pixel pitch that is greater in the first dimension than in the second dimension.