wip

Author: dbochkov-flexcompute

tidy3d/__init__.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from tidy3d.components.boundary import BroadbandModeABCSpec
 from tidy3d.components.material.multi_physics import MultiPhysicsMedium
 from tidy3d.components.material.tcad.charge import (
     ChargeConductorMedium,
@@ -428,6 +429,7 @@ def set_logging_level(level: str) -> None:
     "ABCBoundary",
     "Absorber",
     "AbsorberParams",
+    "BroadbandModeABCSpec",
     "AbstractFieldProjectionData",
     "AbstractMedium",
     "AdmittanceNetwork",

tidy3d/components/boundary.py

@@ -15,7 +15,7 @@
     PlotParams,
     plot_params_absorber,
 )
-from tidy3d.constants import CONDUCTIVITY, EPSILON_0, MU_0, PML_SIGMA
+from tidy3d.constants import C_0, CONDUCTIVITY, EPSILON_0, MU_0, PML_SIGMA
 from tidy3d.exceptions import DataError, SetupError, ValidationError
 from tidy3d.log import log
 
@@ -124,7 +124,62 @@ def _conductivity_only_with_float_permittivity(cls, val, values):
                 "simultaneously with 'permittivity'."
             )
         return val
+    
 
+class BroadbandModeABCSpec(Tidy3dBaseModel):
+    """Specifies the broadband mode absorption boundary conditions. The mode propagation index is approximated by a sum of pole-residue pairs.
+    
+    Example
+    -------
+    >>> broadband_mode_abc_spec = BroadbandModeABCSpec(fmin=100e12, fmax=120e12, num_freqs=3)
+    """
+
+    fmin: pd.PositiveFloat = pd.Field(
+        ...,
+        title="Lower Frequency Bound",
+        description="Lower frequency bound for the broadband mode absorption.",
+    )
+
+    fmax: pd.PositiveFloat = pd.Field(
+        ...,
+        title="Upper Frequency Bound",
+        description="Upper frequency bound for the broadband mode absorption.",
+    )
+
+    num_freqs: pd.PositiveInt = pd.Field(
+        3,
+        title="Number of Frequencies",
+        description="Number of frequencies to use to approximate the mode propagation index. "
+        "The frequencies are evenly spaced between ``fmin`` and ``fmax``.",
+    )
+
+    num_poles: pd.PositiveInt = pd.Field(
+        1,
+        title="Number of Poles",
+        description="Number of poles to use to approximate the mode propagation index.",
+    )
+
+    @classmethod
+    def from_wvl_range(cls, wvl_min: float, wvl_max: float, num_freqs: int = 3, num_poles: int = 1) -> BroadbandModeABCSpec:
+        """Instantiate from a wavelength range.
+        
+        Parameters
+        ----------
+        wvl_min : float
+            Minimum wavelength.
+        wvl_max : float
+            Maximum wavelength.
+        num_freqs : int = 3
+            Number of frequencies to use to approximate the mode propagation index.
+        num_poles : int = 1
+            Number of poles to use to approximate the mode propagation index.
+
+        Returns 
+        -------
+        :class:`BroadbandModeABCSpec`
+            Broadband mode absorption boundary conditions.
+        """
+        return cls(fmin=C_0 / wvl_max, fmax=C_0 / wvl_min, num_freqs=num_freqs, num_poles=num_poles)
 
 class ModeABCBoundary(AbstractABCBoundary):
     """One-way wave equation absorbing boundary conditions for absorbing a waveguide mode."""
@@ -144,7 +199,7 @@ class ModeABCBoundary(AbstractABCBoundary):
         "``num_modes`` in the solver will be set to ``mode_index + 1``.",
     )
 
-    frequency: Optional[pd.PositiveFloat] = pd.Field(
+    frequency: Optional[Union[pd.PositiveFloat, BroadbandModeABCSpec]] = pd.Field(
         None,
         title="Frequency",
         description="Frequency at which the absorbed mode is evaluated. If ``None``, then the central frequency of the source is used.",