Source

The subsequent code will exemplify the process of incorporating a light source and port within a simulation project.

As of now, the source module accommodates the inclusion of mode source and Gaussian source. Furthermore, our platform extends support for ports into both EME and FDTD simulations.

4.1 Waveform

In FDTD simulations, waveforms are utilized to control the bandwidth of the source pluse. You can simply enter the central wavelength and range into the added waveform, and the bandwidth and shape of the pulse source will be automatically calculated.

The syntax and properties for adding waveform are as follows. This function does not return any data.

add(
        name: str,
        type: Literal["gaussian_waveform"],
        property: dict
    )

Set frequency wavelength

Parameter	Type	Default	Description
range_type	string	-	Selects "frequency" or "wavelength".
range_limit	string	-	Selects "min_max" or "center_span".
wavelength_center, frequency_center	number	-	The wavelength center and frequency center.
wavelength_span, frequency_span	number	-	The wavelength span and frequency span.
wavelength_min, wavelength_max	number	-	The minimum wavelength and maximum wavelength.
frequency_min, frequency_max	number	-	The minimum frequency and maximum frequency.

Set time domain

Parameter	Type	Default	Description
pulsetype	string	-	Set the source to standard or broadband.
frequency	number	-	The center frequency of the optical carrier.
pulselength	number	-	The duration of the pulse's full width at half maximum power.
offset	number	-	The time it takes for the source to reach its peak amplitude, measured relative to the start of the simulation.
bandwidth	number	-	The full width at half maximum frequency of the time-domain pulse.

Example:

The following script adds a gaussian waveform by setting the wavelength to 1.55 um and the wavelength span to 0.1 um. This script assumes that FDTD solver has been added to the simulation environment, and the pj is an instance of the project.

waveform name = "wv1550"
wv = pj.Waveform()
wv.add(name=waveform name, type="gaussian_waveform",
        property={"set": "frequency_wavelength",  # selections are ["frequency wavelength","time domain"]
                  "set frequency_wavelength": {
                        "range_type": "wavelength",  # selections are ["frequency","wavelength"]
                        "range_limit": "center_span",  # selections are ["min max","center span"]
                        "wavelength_center": 1.55,
                        "wavelength__span": 0.1,
                    }})

4.2 Mode source

The syntax and properties for adding mode source are as follows. This function does not return any data.

add(
        name: str,
        type: Literal["mode_source"],
        property: dict,
    )

General

Parameter	Type	Default	Description
inject axis	string	-	Selects the mode source propagation along the x-axis, y-axis or zaxis.
direction	string	forward	Selects the forward or backward direction of propagation for the mode source.
amplitude	number	1.0	Specifies the peak amplitude of the electric field, with the unit in V/m.
phase	number	0.0	Specifies the initial phase of the source, with the unit in degrees.
mode_selection	string	-	Selects "fundamental", "fundamental TE", "fundamental TM" or "user select" to inject mode.
mode_index	integer	0	Selects the mode number from the list of calculated modes.
search	string	max_index	Selects "max index" or "near n" to search modes.
n	number	1.0	Searchs modes near the specified effective index.
number_of_trial_modes	integer	20	Records the maximum number of modes in the mode list.
waveform	object	-	Selects the waveform ID from source pulse waveform list.

Geometry

Parameter	Type	Default	Description
x, y, z	number	-	The center position of the mode source.
x span, y span, z span	number	-	X span, Y span, Z span of the mode source.
x min, x max	number	-	X min, X max position of the mode source.
y min, y max	number	-	Y min, Y max position of the mode source.
z min, z max	number	-	Z min, Z max position of the mode source.

Boundary conditions

Select the override default boundary conditions to True, and each boundary condition can be set separately. The optional boundary conditions include "PEC", "PMC", "PML", "symmetric" or "anti symmetric".

If the fraction of magnetic field intensity in PML is greater than the specified threshold, the mode is discarded.

Example:

The following script adds a mode source in FDTD simulation, sets the position and dimension of the light source, as well as the mode profile and waveform. This script assumes that FDTD solver has been added to the simulation environment, and the pj is an instance of the project.

wv_id = wv["waveform_name"]     # Selects the waveform ID from source pulse waveform list.
src = pj.Source()
src.add(name="source", type="mode_source", property={
                    "general": {"amplitude": 1, "phase": 0, "rotations": {"theta": 0, "phi": 0, "rotation_offset": 0},
                    "mode_selection": "fundamental", "waveform": {"waveform_id": wv_id},
                    "inject_axis": "x axis", "direction": "forward"},
                    "geometry": {"x": 0, "x span": 0, "y": 0, "y span": 3, "z": 0, "z span": 3},
                    "modal_analysis": {"mode_removal": {"threshold": 0.01}}})

4.3 Gaussian source

The syntax and properties for adding gaussian source are as follows. This function does not return any data.

add(
        name: str,
        type: Literial["gaussian source"],
        property: dict,
    )

General

Parameter	Type	Default	Description
inject_axis	string	-	Selects the mode source propagation along the x-axis, y-axis or zaxis.
direction	string	forward	Selects the forward or backward direction of propagation for the mode source.
amplitude	number	1.0	Specifies the peak amplitude of the electric field, with the unit in V/m.
phase	number	0.0	Specifies the initial phase of the source, with the unit in degrees.
waveform	object	-	Selects the waveform ID from source pulse waveform list.
angle_theta	number	0	The angle between the propagation direction and the injection axis of source, with the unit in degrees.
angle_phi	number	0	In a right-hand coordinate system, the angle of propagation is rotated around the injection axis of the source.
polarization_angle	number	0	The polarization angle defines the orientation of the injected electric field. A polarization angle of zero degrees indicates P-polarized radiation, while an angle of 90 degrees indicates S-polarized radiation.

beam_settings:
Beam_parameters: Selects "waist_size_and_position" or "beam_size_and_divergence" to set the beam parameters. Waist_radius and distance_from_caist are valid when beam_parameters is set to waist_steze_1and_position. Similarly, beam_radius and divergence_angle are valid when beam_marameters is selected as beam_size_and_divergence.
waist radius: 1/e field (1/e2 power) radius of the beam for a Gaussian beam.
distance from waist: The distance between the injection plane and the beam waist. A positive distance indicates a diverging beam, while a negative distance indicates a converging beam. beam radius: 1/e field (1/e2 power) radius of the beam for a Gaussian beam.
divergence angle: The radiation divergence angle measured in the far field. A positive angle indicates a diverging beam, while a negative angle indicates a converging beam.

Geometry

Parameter	Type	Default	Description
x, y, z	number	-	The center position of the gaussian source.
x span, y span, z span	number	-	X span, Y span, Z span of the gaussian source.
x min, x max	number	-	X min, X max position of the gaussian source.
y min, y max	number	-	Y min, Y max position of the gaussian source.
z min, z max	number	-	Z min, Z max position of the gaussian source.

Example:

The following script adds a gaussian source in FDTD, sets the position and dimension of the light source, as well as the mode profile and waveform. This script assumes that FDTD solver has been added to the simulation environment, and the pj is an instance of the project.

wv_id = wv["waveform_name"]     # Selects the waveform ID from source pulse waveform list.
so = pj.Source()
so.add(name="source", type="gaussian_source", axis="z_backward",
           property={"general": {"angle_theta": 0, "angle phi": 0, "polarization_angle": 0, "waveform": {"waveform_id": wv_id},
                                 "beam_settings": {"calculation method": "use_scalar_approximation",
                                                   "beam_parameters": "waist_size_and_position",
                                                   "waist_radius": 5.2, "distance_from_waist": 1.5}},
                     "geometry": {"x": 4, "x span": 20, "y": 0, "y span": 20, "z": 1.5, "z span": 0}})

4.3 FDTD port

Incorporate a port into the current FDTD simulation project.

add(
        name: str,
        type: Literal["fdtd port"],
        property: dict
    )

Geometry

Parameter	Type	Default	Description
x, y, z	number	-	The center position of the FDTD port.
x span, y span, z span	number	-	X span, Y span, Z span of the FDTD port.
x min, x max	number	-	X min, X max position of the FDTD port.
y min, y max	number	-	Y min, Y max position of the FDTD port.
z min, z max	number	-	Z min, Z max position of the FDTD port.

Boundary conditions

If the fraction of magnetic field intensity in PML is greater than the specified threshold, the mode is discarded.

Example:

The following script adds a port in FDTD simulation, sets the position and dimension of the light source, as well as the mode profile and waveform. This script assumes that FDTD solver has been added to the simulation environment, and the pj is an instance of the project.

wv_id = wv["waveform_name"]     # Selects the waveform ID from source pulse waveform list.
pt = pj.Port(property={"waveform_id": wv_id, "source port": "port_left"})
pt.add(name="port_left", type="fdtd_port",
       property={"geometry": {"x": 0, "x span": 0, "y": 0,
                              "y span": 3, "z": 0, "z span": 3},
                 "modal_properties": {"general": {"inject axis": "x_axis", "direction": "forward",
                                      "mode_selection": "fundamental"}}})

4.4 EME port

The syntax and properties for adding mode source are as follows. This function does not return any data.

add(
        name: str,
        type: Literal["eme_port"],
        property: dict,
    )

Geometry

Parameter	Type	Default	Description
port location	string	-	Set the location of EME port, selections are "left" and "right".
use full simulation span	boolean	True	Set whether the port uses the full simulation area, selections are "True" and "False".
x, y, z	number	-	The center position of the EME port.
x span, y span, z span	number	-	Xspan, Y span, Z span of the EME port.
x min, x max	number	-	X min, X max position of the EME port.
y min, y max	number	-	Y min, Y max position of the EME port.
z min, z max	number	-	Z min, Z max position of the EME port.

EME port

Parameter	Type	Default	Description
mode selection	string		Selects "fundamental", "fundamental TE", "fundamental TM" or "user select" to inject mode.
mode index	integer	0	Selects the mode number from the list of calculated modes.
search	string	max index	Selects "max index" or "near n" to search modes.
n	number	1.0	Searchs modes near the specified effective index.
number of trial modes	integer	20	Records the maximum number of modes in the mode list.

Boundary conditions

If the fraction of magnetic field intensity in PML is greater than the specified threshold, the mode is discarded.

Example: The following script adds ports in EME simulation, selects the mode of "port1" as the source, and sets the calculation fundamental mode and the size is the span of the full simulation area. This script assumes that EME solver has been added to the simulation environment, and the pj is an instance of the project.

pjp = pj.Port(property={"source_port": "port1"})
pjp.add(name="port1", type="eme_port",
        property={"geometry": {"port_location": "left", "use_full_simulation span": True},
                  "eme_port": {"general": {"mode_selection": "user_select", "mode_index": 0, "number_of_trial_modes": 20}}})
pjp.add(name="port2", type="eme_port",
        property={"geometry": {"port_location": "right", "use_full_simulation_span": True},
                  "eme_port": {"general": {"mode_selection": "user_select", "mode_index": 0, "number_of_trial_modes": 20}}})

5 Optical Generation

To calculate optical current in simulations, users need to import optical generation rate data with coordinate information. There are three methods for leading optical generation in simulation:

Users can select "import_data" in the "DataSpace" section and set up property of source.

add_ddm_settings(pj, run_options)

    ds = pj.DataSpace()

    ds.import_data(name="gen", type="generation", property={
        "path": gen_rate_file
    })

    src = pj.Source()
    src.add(name="gen", type="optical_generation", property={
        "general": {"generation_data": ds["gen"], "source_fraction": 0.001},
        "transient": {"envelop": "uniform"}
    })

Name: Users can read and edit the name of this generation rate, which defaults to the name of the imported file.

path--Here it's not empty, meaning that the file at the path will be imported to the DDM solver source_fraction--Set the scaling factor for the light power. The imported optical generation rate will be multiplied by this factor first, and then be used to solve the carrier transport

Transient: Choosing "Uniform" requires users to define "Amplitude" and "Time Delay”. Amplitude: Set the maximum amplitude of the mode source. Time Delay: Define the delay time before opening the source. For Pulse, users should define parameters such as High Amplitude, Low Amplitude, Time Delay, Rising Edge, Falling Edge,Pulse Width and Period. Pulse:

High Amplitude: Amplitude of pulse after on shutter.
Low Amplitude: Amplitude of pulse after off shutter.
Time Delay: Time Delay, Rising Edge, Falling Edge, Pulse Width, and Period: Specify timing and duration parameters. The period's duration should be large.

Source

4.1 Waveform​

Set frequency wavelength​

Set time domain​

4.2 Mode source​

General​

Geometry​

Boundary conditions​

Modal analysis​

4.3 Gaussian source​

General​

Geometry​

4.3 FDTD port​

Geometry​

Boundary conditions​

Modal analysis​

4.4 EME port​

Geometry​

EME port​

Boundary conditions​

Modal analysis​

5 Optical Generation​

4.1 Waveform

Set frequency wavelength

Set time domain

4.2 Mode source

General

Geometry

Boundary conditions

Modal analysis

4.3 Gaussian source

General

Geometry

4.3 FDTD port

Geometry

Boundary conditions

Modal analysis

4.4 EME port

Geometry

EME port

Boundary conditions

Modal analysis

5 Optical Generation