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Introduction to Kallistos. B. Luyssaert. 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)
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Introduction to Kallistos B. Luyssaert
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
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
W L D Defined structure = MMI-coupler (defined using shapes, 2D, no PML)
Click Optimiser Symbol and Optimiser Window appears, note the 8 different symbols
Symbol1: select a node Select the node of the project you want to be optimised, in this case example_mmi
Symbol2: show node Trivial
Symbol3: Settings, PART 1: Optimiser Settings Global : search through the entire parameter space
Symbol3: Settings, PART 2: Independent Variables Define the parameters you want to be changed and the boundaries of the parameter space
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
Symbol3: Settings, PART 4: Objective • 4 predefined objective functions: • total power • forward power • backward power • mode power User Defined Objectives: see manual
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, ...
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
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
Symbol5: Run, Local Optimiser Optimise locally around best point
Symbol5: Run, Local Optimiser, Line Path View Watch the evolution of the local optimisation Top: evolution of objective function Bottom: evolution of parameters
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