© intec 2000

Introduction to Kallistos

B. Luyssaert

© intec 2003 http://www.photonics.intec.rug.ac.be

What is Kallistos ?

• Although commercialised by another company, Kallistos is an extension of FimmWave

• Optimisation tool capable of automatically improving existing photonic devices

• Contains several robust optimisers (local and global)

• Takes advantage of eigenmode expansion equations

© intec 2003 http://www.photonics.intec.rug.ac.be

The Following

• assumes a basic knowledge of FimmWave and FimmProp

• is based on an example that is delivered with Kallistos

project: learn_kallistos.prj

source node: example_MMI

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Defined structure = MMI-coupler (defined using shapes, 2D, no PML)

DW

L

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Field plot (clearly not in an optimum)

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Right click project and add Kallistos Optimiser

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Click Optimiser Symbol and Optimiser Window appears, note the 8 different symbols

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Symbol1: select a node

Select the node of the project you want to be optimised, in this case example_mmi

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Symbol2: show node

Trivial

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Symbol3: Settings, PART 1: Optimiser Settings

Global :

search through the entire parameter space

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Symbol3: Settings, PART 2: Independent Variables

Define the parameters you want to be changed and the boundaries of the parameter space

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Symbol3: Settings, PART 3: Dependent Variables

Cdev = current device = selected node

To know the number of each shape = watch command-line window during constructing of the node

TIP:

<TAB> = autocompletion

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Symbol3: Settings, PART 4: Objective

4 predefined objective functions:

• total power

• forward power

• backward power

• mode power

User Defined Objectives: see manual

© intec 2003 http://www.photonics.intec.rug.ac.be

Symbol5: Run, PART 1: Tree View

Watch the evolution of the optimisation

Blue is bad, Red is good

Crude scanning:

Parameter space is divided in 2, middle point is evaluated, then best part is again divided in 2, evaluated, ...

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Symbol5: Run, PART 2: Hypercube View

Watch the evolution of the optimisation

Blue is bad, Red is good

View a cross section of the parameter space hypercube and the quality of the points projected onto it

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Symbol5: Run, PART 3: Data View

Watch the evolution of the optimisation

Shows the details of every calculated point and also the very best point with the related parameter values

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Symbol5: Run, Update Initial

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Symbol5: Run, Local Optimiser

Optimise locally around best point

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Symbol5: Run, Local Optimiser, Line Path View

Watch the evolution of the local optimisation

Top:

evolution of objective function

Bottom:

evolution of parameters

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Symbol8: Display node

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Symbol7: Open Previous run

Use: Suppose that you also would like to locally optimise the second best point of the global run

Symbol6: Delete Current Run

Symbol4: Block Editor

Use: Input in text format, rather intuitive

© intec 2003 http://www.photonics.intec.rug.ac.be

Enjoy Kallistos !