Wavelength Selective Switch Compensating Position Shift

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Solution Overview

Problem

Wavelength selective switches experience a shift in light-condensing position due to the arrangement of input and output ports, leading to curvature of field and beam broadening, which degrades communication quality and coupling efficiency, especially as the number of ports increases.

Innovation Solution

Incorporating a light-condensing position shift compensating element in the optical path between the input port and the dispersive portion, which compensates for the position shift relative to the deflection element, ensuring accurate light condensation and improved communication quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple input/output ports are arranged in series to increase port quantity, then the number of ports increases, but light-condensing position shift and beam broadening worsen

Engineering Contradiction:

Improvenumber of portsVSAvoidlight-condensing position accuracy

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent introduces a new spatial dimension by arranging input and output ports in a two-dimensional array configuration rather than a simple series arrangement. This dimensional change allows light from multiple ports to be properly focused onto the deflection element surface, resolving the position shift problem that occurs when increasing port quantity in a linear fashion.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies different optical characteristics to different regions of the optical system. Specifically, it uses a cylindrical lens with optical power in the direction perpendicular to the array direction to correct beam broadening in that specific dimension, while maintaining appropriate beam characteristics in the array direction. This localized optical correction addresses the position accuracy issue without compromising port quantity.

Inventive Principle:

Principle #3Local quality

2Reliability

If light is condensed onto deflection element surface, then coupling efficiency improves, but position shift causes spot size increase and efficiency degradation

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidspot size control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the optical parameters of the system by introducing a cylindrical lens with specific optical power in the direction perpendicular to the array direction. This parameter change corrects the beam broadening effect, maintaining a tight spot size on the deflection element surface and thereby preserving high coupling efficiency despite the presence of multiple ports.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If beam width is reduced in dispersion direction for wider transmission band, then transmission band increases, but coupling efficiency becomes more susceptible to position shift

Engineering Contradiction:

Improvetransmission band widthVSAvoidcoupling efficiency stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by pre-correcting the beam broadening effect using a cylindrical lens before the light reaches the deflection element. This preliminary correction ensures that even when the beam width is reduced in the dispersion direction to enable wider transmission bands, the coupling efficiency remains stable and less susceptible to position shift variations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The compensating element effectively reduces spot size on the deflection element surface, enhancing coupling efficiency and communication quality by maintaining a stable light-condensing position, even with multiple ports, and supports wider transmission bands for faster optical signals.

Implementation Method 1

dispersed into wavelengths by a diffraction grating (dispersive element)

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

condensed for each wavelength by a condenser lens onto different mirror elements (deflection elements)

Methodology Applied

Scientific EffectFocusing: Lens

Implementation Method 3

deflected in different directions for each wavelength and outputted therefrom

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS8634129B2Wavelength selective switch

Publication Date: 2014.01.21 WELLS FARGO BANK NA

AI summary

Provided is a wavelength selective switch which includes: at least one input port; a dispersive portion for dispersing wavelength-multiplexed light input from the input port into wavelength-demultiplexed lights; a condenser element for condensing the wavelength-demultiplexed lights dispersed by the dispersive portion; a deflection portion having deflection elements for deflecting, for each wavelength-demultiplexed light condensed by the condenser element; at least one output port for outputting the wavelength-demultiplexed lights deflected by the deflection portion. A light-condensing position shift compensating element is disposed in an optical path between the input port and the dispersive portion or in the dispersive portion, for compensating light-condensing position shift of the wavelength-demultiplexed lights relative to the deflection element, light-condensing position shift being generated based on the arrangement of the input ports.