Waveguide InputΒΆ

Learning targets

  • Transparent boundary conditions in 3D
  • Inhomogeneous exterior domain: waveguides and layered media
  • Boolean Difference

This example describes a computational domain with transparent boundary conditions at all sides. In this case, waveguides are included some of which touch the boundary of the computational domain, and which are modeled to extend also to the exterior domain. Further, a substrate is included which also extends to the exterior domain.

The following figure shows an image of parts of the geometry and mesh:

_images/ex3d_waveguide_input_mesh.png

The waveguides exhibit a sidewall angle for the vertical flanks. This is achieved by a normal displacement of the waveguide structure during the extrusion process. To ease this we use the Boolean difference operator to form the ring resonator, so that we can apply the normal shift on the entire ring composed from the different geometrical primitives. For the straight waveguide adjacent to the ring we only apply the displacements on segments which are not extended to the exterior domain. Here, a SegmentNormalDisplacement is used inplace of the NormalDisplacement.

Input Files

  • layout.jcm [ASCII]

      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    
    Layout3D { 
      Name = "TutorialExample3D" 
      UnitOfLength = 1e-06 
      
      MeshOptions {
        MaximumSideLength = 1 
        MinimumMeshAngle = 18 
    
      }
      Extrusion {
        Objects {
          Parallelogram {  
            DomainId = 10  
            Priority = ComputationalDomain
            Name = "ComputationalDomain"
            Width = 14
            Height = 14
            GlobalPosition = [-5 0]
            Boundary { 
              Class = Transparent 
            } 
          } 
          
          Parallelogram {  
            Name = "Waveguide"  
            DomainId = 20  
            Priority = 1 
            Width = 0.5
            Height = 14
            SegmentNormalDisplacement {           
              Segment = [2 4]
              Value {
                PiecewiseLinear {
                  AtInterface {
                    Interface = 1              
                    Value = 0
                  }
                  AtInterface {
                    Interface = 2
                    Value = 0.05
                  }
                }
              }
            }       
            MeshOptions {
              MaximumSideLength = 0.45 
            }
          } 
          
          BooleanOperation {
            Operator = Difference
            DomainId = 20
            Name = "Ring"
            A {
              Parallelogram {
                Name = "P"
                Width = 10.5
                Height = 2.5
              }
              CircleSector {
                Radius = 5.25
                RefineAll = 2
                AngleRange = [0 180]
                Alignment {
                  Parent {
                    Domain = "P"
                    Port = North
                  }
                  Orientation = AntiParallel
                }
              }
              CircleSector {
                AngleRange = [0 180]
                Radius = 5.25
                RefineAll = 2
                Alignment {
                  Parent {
                    Domain = "P"
                    Port = South
                  }
                  Orientation = AntiParallel
                }
              }
            }
            
            B {
              Parallelogram {
                Name = "P"
                DomainId = 25
                Width = 9.5
                Height = 2.5
              }
              CircleSector {
                Radius = 4.75
                RefineAll = 2
                AngleRange = [0 180]
                
                Alignment {
                  Parent {
                    Domain = "P"
                    Port = North
                  }
                  Orientation = AntiParallel
                }
              }
              CircleSector {
                Radius = 4.75
                RefineAll = 2
                AngleRange = [0 180]
                Alignment {
                  Parent {
                    Domain = "P"
                    Port = South
                  }
                  Orientation = AntiParallel
                }
              }
            }
            Alignment {
              Parent {
                Domain = "Waveguide"
                Port = Center
              }
              Orientation = Parallel
              Displacement = [-5.8 0.0]
            }
            NormalDisplacement { 
              PiecewiseLinear {
                AtInterface {
                  Interface = 1
                  NormalDisplacement = 0
                }
                AtInterface {
                  Interface = 2
                  NormalDisplacement = 0.05
                }
              }
            }             
          }
        }     
        MultiLayer { 
          Layer {  
            Thickness = 0.225 
            DomainIdMapping = [10 1, 20 1] 
          } 
          LayerInterface {
            GlobalZ = 0.0
          }
          Layer {  
            Thickness = 0.25 
            DomainIdMapping = [10 3, 20 2] 
          } 
          Layer {  
            Thickness = 0.225 
            DomainIdMapping = [10 3, 20 3] 
          } 
        } 
      } 
    }