Source code for finesse.components.optical_bandpass

from finesse.components.general import Connector, InteractionType
from finesse.components.node import NodeDirection, NodeType
from finesse.exceptions import FinesseException
from finesse.parameter import float_parameter
from finesse.utilities import refractive_index


[docs]@float_parameter("fc", "Central frequency", units="Hz") @float_parameter("bandwidth", "Bandpass bandwidth", units="Hz") # IMPORTANT: renaming this class impacts the katscript spec and should be avoided! class OpticalBandpassFilter(Connector): """An idealised optical bandpass filter that will transmit an optical frequency around some central frequency with a 3dB bandwidth. Notes ----- Currently this is a classical component. No quantum noise losses are applied to any filtered fields or modes, which means no additional vaccum noise is injected back into the system for this lost information. Parameters ---------- name : str Name of element fc : float, symbol Central frequency bandwidth : float, symbol Filter 3dB bandwidth filter_hom : [tuple | None], optional Individual higher order modes can be filtered and transmitted by setting this to a tuple of (n, m). If ``None`` then no mode filtering is done. This cannot be changed during a simulation. """ def __init__(self, name, fc=0, bandwidth=1000, filter_hom=None): super().__init__(name) self.fc = fc self.bandwidth = bandwidth self.filter_hom = filter_hom self._add_port("p1", NodeType.OPTICAL) self.p1._add_node("i", NodeDirection.INPUT) self.p1._add_node("o", NodeDirection.OUTPUT) self._add_port("p2", NodeType.OPTICAL) self.p2._add_node("i", NodeDirection.INPUT) self.p2._add_node("o", NodeDirection.OUTPUT) # optic to optic couplings self._register_node_coupling( "P1i_P2o", self.p1.i, self.p2.o, interaction_type=InteractionType.TRANSMISSION, ) self._register_node_coupling( "P2i_P1o", self.p2.i, self.p1.o, interaction_type=InteractionType.TRANSMISSION, ) def _get_workspace(self, sim): from finesse.simulations.basematrix import CarrierSignalMatrixSimulation if isinstance(sim, CarrierSignalMatrixSimulation): _, is_changing = self._eval_parameters() refill = ( sim.is_component_in_mismatch_couplings(self) or len(is_changing) or sim.carrier.any_frequencies_changing or (sim.signal.any_frequencies_changing if sim.signal else False) ) from .modal.optical_bandpass import ( optical_bandpass_carrier_fill, optical_bandpass_signal_fill, OpticalBandpassWorkspace, ) hom_filter_index = None if self.filter_hom is not None: if sim.is_modal: try: hom_filter_index = sim.model.mode_index_map[ tuple(self.filter_hom) ] except KeyError: raise FinesseException( f"No HG mode {self.filter_hom} was found in this model." ) else: hom_filter_index = 0 # planewave ws = OpticalBandpassWorkspace(self, sim, hom_filter_index) # This assumes that nr1/nr2 cannot change during a simulation ws.nr1 = refractive_index(self.p1) ws.nr2 = refractive_index(self.p2) # TODO ddb refractive index should be equal on # both sides of the lens as we are using the thin # lens approximation assert ws.nr1 == ws.nr2 ws.carrier.add_fill_function(optical_bandpass_carrier_fill, refill) ws.signal.add_fill_function(optical_bandpass_signal_fill, refill) if sim.is_modal: # Set the coupling matrix information # ABCDs are same in each direction ws.set_knm_info( "P1i_P2o", nr_from=ws.nr1, nr_to=ws.nr2, is_transmission=True, ) # TODO nr reversed here for now until it's forced to be same on both sides ws.set_knm_info( "P2i_P1o", nr_from=ws.nr2, nr_to=ws.nr1, is_transmission=True, ) return ws else: raise Exception( f"Optical bandpass filter does not handle a simulation of type {sim}" )