tidy3d.ModeMonitor

class tidy3d.ModeMonitor

Monitor that records amplitudes from modal decomposition of fields on plane.

Parameters

• center (Tuple[float, float, float] = (0.0, 0.0, 0.0)) – [units = um]. Center of object in x, y, and z.

• size (Tuple[NonNegativeFloat, NonNegativeFloat, NonNegativeFloat] = None) – [units = um]. Size in x, y, and z directions.

• name (ConstrainedStrValue = None) – Unique name for monitor.

• freqs (Union[List[float], tidynumpy, NumpyArray, List] = None) – [units = Hz]. Array or list of frequencies stored by the field monitor.

• mode_spec (ModeSpec = None) – Parameters to feed to mode solver which determine modes measured by monitor.

Example

>>> mode_spec = ModeSpec(num_modes=3)
>>> monitor = ModeMonitor(
...     center=(1,2,3),
...     size=(2,2,0),
...     freqs=[200e12, 210e12],
...     mode_spec=mode_spec,
...     name='mode_monitor')

Show JSON schema

{
   "title": "ModeMonitor",
   "description": ":class:`Monitor` that records amplitudes from modal decomposition of fields on plane.\n\nParameters\n----------\ncenter : Tuple[float, float, float] = (0.0, 0.0, 0.0)\n    [units = um].  Center of object in x, y, and z.\nsize : Tuple[NonNegativeFloat, NonNegativeFloat, NonNegativeFloat] = None\n    [units = um].  Size in x, y, and z directions.\nname : ConstrainedStrValue = None\n    Unique name for monitor.\nfreqs : Union[List[float], tidynumpy, NumpyArray, List] = None\n    [units = Hz].  Array or list of frequencies stored by the field monitor.\nmode_spec : ModeSpec = None\n    Parameters to feed to mode solver which determine modes measured by monitor.\n\nExample\n-------\n>>> mode_spec = ModeSpec(num_modes=3)\n>>> monitor = ModeMonitor(\n...     center=(1,2,3),\n...     size=(2,2,0),\n...     freqs=[200e12, 210e12],\n...     mode_spec=mode_spec,\n...     name='mode_monitor')",
   "type": "object",
   "properties": {
      "center": {
         "title": "Center",
         "description": "Center of object in x, y, and z.",
         "default": [
            0.0,
            0.0,
            0.0
         ],
         "units": "um",
         "type": "array",
         "minItems": 3,
         "maxItems": 3,
         "items": [
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               "type": "number"
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            {
               "type": "number"
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         "title": "Type",
         "default": "ModeMonitor",
         "enum": [
            "ModeMonitor"
         ],
         "type": "string"
      },
      "size": {
         "title": "Size",
         "description": "Size in x, y, and z directions.",
         "units": "um",
         "type": "array",
         "minItems": 3,
         "maxItems": 3,
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               "minimum": 0
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      },
      "name": {
         "title": "Name",
         "description": "Unique name for monitor.",
         "minLength": 1,
         "type": "string"
      },
      "freqs": {
         "title": "Frequencies",
         "description": "Array or list of frequencies stored by the field monitor.",
         "units": "Hz",
         "anyOf": [
            {
               "type": "array",
               "items": {
                  "type": "number"
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            },
            {
               "title": "NumpyArray",
               "description": "Wrapper around numpy arrays that has a well defined json schema.",
               "type": "object",
               "properties": {
                  "data_list": {
                     "title": "Data List",
                     "type": "array",
                     "items": {}
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               "required": [
                  "data_list"
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            },
            {
               "$ref": "#/definitions/NumpyArray"
            },
            {
               "type": "array",
               "items": {}
            }
         ]
      },
      "mode_spec": {
         "title": "Mode Specification",
         "description": "Parameters to feed to mode solver which determine modes measured by monitor.",
         "allOf": [
            {
               "$ref": "#/definitions/ModeSpec"
            }
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   "required": [
      "size",
      "name",
      "freqs",
      "mode_spec"
   ],
   "additionalProperties": false,
   "definitions": {
      "NumpyArray": {
         "title": "NumpyArray",
         "description": "Wrapper around numpy arrays that has a well defined json schema.",
         "type": "object",
         "properties": {
            "data_list": {
               "title": "Data List",
               "type": "array",
               "items": {}
            }
         },
         "required": [
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      },
      "ModeSpec": {
         "title": "ModeSpec",
         "description": "Stores specifications for the mode solver to find an electromagntic mode.\nNote, the planar axes are found by popping the injection axis from {x,y,z}.\nFor example, if injection axis is y, the planar axes are ordered {x,z}.\n\nParameters\n----------\nnum_modes : PositiveInt = 1\n    Number of modes returned by mode solver.\ntarget_neff : Optional[PositiveFloat] = None\n    Guess for effective index of the mode.\nnum_pml : Tuple[NonNegativeInt, NonNegativeInt] = (0, 0)\n    Number of standard pml layers to add in the two tangential axes.\nsort_by : Literal['largest_neff', 'te_fraction', 'tm_fraction'] = largest_neff\n    The solver will always compute the ``num_modes`` modes closest to the ``target_neff``, but they can be reordered by the largest ``te_fraction``, defined as the integral of the intensity of the E-field component parallel to the first plane axis normalized to the total in-plane E-field intensity. Similarly, ``tm_fraction`` uses the E field component parallel to the second plane axis.\nangle_theta : float = 0.0\n    [units = rad].  Polar angle of the propagation axis from the injection axis.\nangle_phi : float = 0.0\n    [units = rad].  Azimuth angle of the propagation axis in the plane orthogonal to the injection axis.\nbend_radius : Optional[float] = None\n    [units = um].  A curvature radius for simulation of waveguide bends. Can be negative, in which case the mode plane center has a smaller value than the curvature center along the tangential axis perpendicular to the bend axis.\nbend_axis : Optional[Literal[0, 1]] = None\n    Index into the two tangential axes defining the normal to the plane in which the bend lies. This must be provided if ``bend_radius`` is not ``None``. For example, for a ring in the global xy-plane, and a mode plane in either the xz or the yz plane, the ``bend_axis`` is always 1 (the global z axis).\n\nExample\n-------\n>>> mode_spec = ModeSpec(num_modes=3, target_neff=1.5)",
         "type": "object",
         "properties": {
            "num_modes": {
               "title": "Number of modes",
               "description": "Number of modes returned by mode solver.",
               "default": 1,
               "exclusiveMinimum": 0,
               "type": "integer"
            },
            "target_neff": {
               "title": "Target effective index",
               "description": "Guess for effective index of the mode.",
               "exclusiveMinimum": 0,
               "type": "number"
            },
            "num_pml": {
               "title": "Number of PML layers",
               "description": "Number of standard pml layers to add in the two tangential axes.",
               "default": [
                  0,
                  0
               ],
               "type": "array",
               "minItems": 2,
               "maxItems": 2,
               "items": [
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                     "type": "integer",
                     "minimum": 0
                  },
                  {
                     "type": "integer",
                     "minimum": 0
                  }
               ]
            },
            "sort_by": {
               "title": "Ordering of the returned modes",
               "description": "The solver will always compute the ``num_modes`` modes closest to the ``target_neff``, but they can be reordered by the largest ``te_fraction``, defined as the integral of the intensity of the E-field component parallel to the first plane axis normalized to the total in-plane E-field intensity. Similarly, ``tm_fraction`` uses the E field component parallel to the second plane axis.",
               "default": "largest_neff",
               "enum": [
                  "largest_neff",
                  "te_fraction",
                  "tm_fraction"
               ],
               "type": "string"
            },
            "angle_theta": {
               "title": "Polar Angle",
               "description": "Polar angle of the propagation axis from the injection axis.",
               "default": 0.0,
               "units": "rad",
               "type": "number"
            },
            "angle_phi": {
               "title": "Azimuth Angle",
               "description": "Azimuth angle of the propagation axis in the plane orthogonal to the injection axis.",
               "default": 0.0,
               "units": "rad",
               "type": "number"
            },
            "bend_radius": {
               "title": "Bend radius",
               "description": "A curvature radius for simulation of waveguide bends. Can be negative, in which case the mode plane center has a smaller value than the curvature center along the tangential axis perpendicular to the bend axis.",
               "units": "um",
               "type": "number"
            },
            "bend_axis": {
               "title": "Bend axis",
               "description": "Index into the two tangential axes defining the normal to the plane in which the bend lies. This must be provided if ``bend_radius`` is not ``None``. For example, for a ring in the global xy-plane, and a mode plane in either the xz or the yz plane, the ``bend_axis`` is always 1 (the global z axis).",
               "enum": [
                  0,
                  1
               ],
               "type": "integer"
            },
            "type": {
               "title": "Type",
               "default": "ModeSpec",
               "enum": [
                  "ModeSpec"
               ],
               "type": "string"
            }
         },
         "additionalProperties": false
      }
   }
}

Fields

storage_size(num_cells: int, tmesh: int) → int

Size of monitor storage given the number of points after discretization.

Parameters

• num_cells (int) – Number of grid cells within the monitor after discretization by a Simulation.

• tmesh (Array) – The discretized time mesh of a Simulation.

Returns

Number of bytes to be stored in monitor.

Return type

int