Grating Optimization Using optiSLang in VirtualLab Fusion
The optimization of modern optical systems generally involves a large number of parameters. For example, when optimizing a grating, not only the geometric parameters of the grating need to be considered, but also the required direction of incidence. As the number of parameters increases, the optimization becomes more and more challenging. For this case, VirtualLab Fusion provides an interface with Dynardo’s optiSLang software , which allows the use of different advanced optimization algorithms.
VirtualLab Fusion and optiSLang interface
VirtualLab Fusion is a flexible and customizable modeling tool platform that can simulate complex optical devices, such as a set of plane waves coupled into an optical waveguide.
optiSLang is a software platform that includes advanced tools including sensitivity analysis, multivariate and multidisciplinary optimization, robustness assessment, reliability analysis and robust design optimization.
The combination of the two software platforms enables advanced grating structures such as smart waveguide coupling.
VirtualLab Fusion – Optical setup initialization
Initial installation
─ In general, any optical system defined in VirtualLab can be optimized using optiSLang.
─ The optical system in this example consists of a plane wave light source and a waveguide-coupled detector for periodic media.
VirtualLab Fusion – Waveguide Coupled Detectors
Waveguide coupling detection
─ A waveguide coupled detector is a special tool used to detect the efficiency of a periodic structure at a specific angle range.
─ Periodic structures can be defined or loaded from a catalog in the detector’s edit dialog.
VirtualLab Fusion – Waveguide Coupled Detectors
Waveguide coupling detection
─ In this example, a tilted grating is used.
VirtualLab Fusion – Waveguide Coupled Detectors
Waveguide coupling detection
─ In this example, a tilted grating is used.
VirtualLab Fusion – Waveguide Coupled Detectors
Waveguide coupling detection
─ The incident angle range of the input light source is specified in the detector editing dialog box.
─ Defined by the minimum and maximum Cartesian angles alpha and beta and their number of sampling points.
VirtualLab Fusion – Waveguide Coupling
Waveguide coupling detection
─ The average and uniform contrast can be calculated from the detected efficiency and given in the Detector Results tab.
─ As a result, the detector can be used to evaluate periodic structures within a certain angular range.
VirtualLab Fusion – Export LPD to OPtiSLang
Output LPD to OPtiSLang
─ File→Export→Export to optiSlang Project
VirtualLab Fusion – Export LPD to OPtiSLang
Output LPD to OPtiSLang
─ File→Export→Export to optiSlang Project
─ Outputs LPD files and generates the necessary optical device files for input to optiSLang.
VirtualLab Fusion – Export LPD to OPtiSLang
Output LPD to OPtiSLang
─ In the output dialog window.
The parameter space can be defined, and includes the range of parameter variation.
You can choose the output folder to save to.
You can specify a simulation engine for analysis.
optiSLang – Initialization Optimization
Setting up the solver system
─ File→New project…
optiSLang – Initialization Optimization
Setting up the solver system
─ Go ahead and drag the Solver wizard to the Scenery window.
─ Opens a dialog box listing several solver examples.
─ VirtualLab must be selected in the Solver example.
optiSLang – Initialization Optimization
Setting up the solver system
─ Then a file dialog will pop up and you must open the system.lpd file exported by VirtualLab.
optiSLang – Initialization Optimization
Parameterized Solver System
─ Parameterized solver systems contain the corresponding VirtualLab files and two XML files containing parameters and results for defining the optimization function.
─ Be sure to save your plan.
optiSLang – Initialization Optimization
Parameterized Solver System
─ Run the solver system to check that it works properly and gives the expected results.
optiSLang – Initialization Optimization
Parameterized Solver System
─ Run the solver system to check that it works properly and gives the expected results.
─ Parameters and results can be examined by double-clicking the Parametric Solver System window in the Result Design tab.
optiSLang – Settings Optimization
Parameterized Solver System
─ optiSLang can optimize optical systems with multiple objective functions.
─ This can be defined in the Criteria tab of the Parametric solver system configuration.
optiSLang – Settings Optimization
Parameterized Solver System
─ You can define the first objective function by dragging Uniformity Contrast to the Objective Minimize criterion.
─ Therefore the optimization algorithm will try to minimize the uniformity contrast as much as possible.
optiSLang – Settings Optimization
Parameterized Solver System
─ You can define a second objective function by dragging Mean to the Objective Maximize criterion.
─ Therefore, the optimization algorithm will try to maximize the average efficiency.
─ This operation is called multi-objective optimization.
optiSLang – Settings Optimization
Optimization Wizard
─ The next step is to use the optimization wizard via drag and drop.
optiSLang – Settings Optimization
Optimization Wizard
─ In the first step, various system parameters are provided, including their specified value ranges.
─ In addition, optiSLang provides a visual value range with the initial value marked.
─ Then click Next.
