A statistically enabled electro-optic phase shifter model based on free-carrier plasma dispersion effects. This device is assumed to be composed of an active region in the middle, connected to the input/output ports by passive transitions and waveguides. For a diagram of the expected layout, see the Internal Model Diagram in photonic model page.
The statistical parameters are delta_width, delta_height, delta_ridge_height, delta_Vpi_Lpi, and delta_IL.
For information on statistical CMLs, see Statistical CMLs.
Note: For legacy data format (2022 R2.4 and older) please visit following link:
Electrical Phase Shifter (Statistical) - Lumfoundry Template (Legacy)
Template: ps_pn_stat_te_c (lumped model)
Photonic Model: phase_shifter_electrical
Quality Assurance Test: phase_shifter_electrical QA
Statistically Enabled Parameters: neff (active wg), ng (active wg), Vpi_Lpi, and IL
Parameters: length of the active region.
Interoperability with Cadence Virtuoso:
- Circuit design flows using INTERCONNECT model: Yes.
- Circuit design flow using photonic Verilog-A model: Yes.
Modeling Data
The source data template for a Electrical Phase Shifter element can divided into two sections.
- For new users (continue with following section: Basic data requirement section)
- Advanced users ( continue with section: Complete Data Requirement )
In order to get started and add a custom electrical phase shifter element into the compact model library (CML), a user only needs to edit the data listed in the ‘basic data requirement section’ below, while all other data (i.e. the advanced element data) can be left as is.
Note: Advanced users please jump start with Complete Data Requirement (for advanced users) section.
Basic data requirement section (for new users)
The basic or minimum data required to build the electrical phase shifter model is described below.
general
"general" is a struct with following fields:
Field | Type | Description |
---|---|---|
description | string | A string containing a brief description of the model, which will be displayed to the end user. |
notes | cell |
A cell array providing model notes which will be displayed to the end user. Each element of the cell is a struct with the fields:
|
ports
"ports" is a struct with following fields:
Field | Type | Description |
---|---|---|
opt_1 |
struct with fields described in table below | Port definition corresponding to the optical ports |
opt_2 |
||
ele_an |
Port definition corresponding to the electrical cathode and anode | |
ele_cat |
Each struct above consists of following fields:
Field | Type | Description |
---|---|---|
name | string | The name of the port, which will be visible to the end user. This name should be consistent with the name that will be used for netlisting. |
dir | string | The directionality of the port, either "Input", "Output", or "Bidirectional" |
pos | string |
The side of the model which the port will be displayed on, either "Left", "Right", "Top", or "Bottom" |
order | number |
The order in which the port is listed in a netlist. |
parameters
"parameters" is a struct with following fields:
Field | Type | Description |
---|---|---|
wg_length
|
struct with fields described in table below |
The length of the active waveguide region. |
Each struct above consists of following fields:
Field | Type | Description |
---|---|---|
default |
number |
The nominal value of the parameter in SI unit. |
min
|
number |
Minimum allowed value if the visible_to_user is set to True. |
max
|
number |
Maximum allowed value if the visible_to_user is set to True. |
model_data
"model_data" is a struct with following fields:
Field | Type | Description |
---|---|---|
mode_data |
cell |
M x 1 cell array where M is the number of modes. Each element of the cell is a struct with fields:
Notes: This model only supports up to two modes. |
bandwidth_data
|
struct |
The 3-dB cutoff frequency (Hz) of the electrical modulator as a function of bias voltage (V). The required fields are:
Notes:
|
elec_eq_ckt_data
|
struct with fields described in |
Data required for modeling the electrical equivalent circuit for accurate electro-optic simulations. For more information on the electrical equivalent circuit, see phase_shifter_electrical - CML Compiler Model. |
elec_eq_ckt_data
In order to model the electrical equivalent circuit for the electrical phase shifter, either a travelling wave model or a lumped model may be used. The model type used is determined by the inclusion or exclusion of the electrical termination port in "ports" section.
Lumped Model
This data will only be used if the travelling wave electrode is disabled, which is done by not including the electrical termination port (ele_term). The RC data within this section is used to construct an electrical equivalent circuit which captures the bandwidth and loading effects of the electrical phase shifters when the compact model is simulated using Cadence Spectre. When the compact model is used standalone in INTERCONNECT, the electrical bandwidth is captured by an INTERCONNECT electrical low pass filter, which has a 3dB cut-off frequency calculated based on the RC data described in this section. The RC parameter data is optional, and if not provided, it will be automatically back-calculated based on the device’s bandwidth_data by CML Compiler.
For more information on the equivalent circuit for the depletion mode phase shifter, see Electrical Equivalent Circuit in photonic model page.
Field | Type | Description |
---|---|---|
Cj_data |
struct |
Junction capacitance (F) of the electrical phase shifter as a function of bias voltage, and the required fields are:
Note: Junction capacitance must be provided for at least 2 bias points. |
Rj |
number |
Junction resistance (\(\Omega \cdot m\)) of the phase shifter |
Rp |
number |
Contact resistance (\(\Omega)\) of the metal pad |
Cp |
umber |
Parasitic capacitance (F) between metal pads |
FOMs
"FOMs" is a struct with fields below. This data is required for CML Compiler to run quality-assurance tests on the final model. It is also optionally used by CML Compiler to fine-tune the internal model to provide the expected behavior. If the source physical data provided for the model is not consistent with the figures of merit (FOMs) provided (meaning the actual FOM values resulting from physical parameters differ from provided FOM data), the model can tune the provided physical data to match the FOMs to the provided values. For more information, see Tuning Active Compact Models.
Field | Type | Description |
---|---|---|
IL |
struct with fields described in table below |
The overall insertion loss (dB) of the phase shifter at zero bias.
|
Vpi_Lpi |
struct with fields described in table below |
Large signal Vpi.Lpi (V-m) of the electrical phase shifter (as explained in the Vpi Data Visualization in photonic model page section) for voltage range described by "ref1" and "ref2" in the struct. |
Each struct above consists of following fields:
Note: The following variables can be provided as a 2x1 matrix if more than one mode is supported.
Field | Type | Description |
---|---|---|
value |
number |
The nominal value for the FOM in SI unit. |
tuning |
boolean |
A flag to enable or disable FOM tuning. |
min
|
number |
Minimum allowed value in SI unit if visible_to_user is set to True. |
max
|
number |
Maximum allowed value in SI unit if visible_to_user is set to True. |
ref1 (if applicable) |
number |
Point(s) at which the nominal FOM were measured. This parameter can be voltage or power data points depending on the FOM definition. |
ref2 (if applicable)
|
number |
Complete data requirement (for advanced users)
The complete data section provides a complete reference of data supported by the electrical phase shifter model including the basic required data described in the previous section. The description of all the fields in the electrical phase shifter source data template are described below.
general
"general" is a struct with following fields:
[[snippet||11549514081811]]
ports
"ports" is a struct with following fields:
[[snippet||12092461714963]]
Each struct above consists of following fields:
[[snippet||11549759363603]]
parameters
"parameters" is a struct with following fields:
[[snippet||12092500096659]]
Each struct above consists of following fields:
[[snippet||11720299494931]]
model_data
"model_data" is a struct with following fields:
[[snippet||12115391452563]]
bandwidth_data
|
struct |
The 3-dB cutoff frequency (Hz) of the electrical modulator as a function of bias voltage (V). The required fields are:
Notes:
|
[[snippet||12119306843283]]
Structs listing mode properties for different waveguide sections consist of following fields:
[[snippet||11653970537235]]
FOMs
"FOMs" is a struct with fields below. This data is required for CML Compiler to run quality-assurance tests on the final model. It is also optionally used by CML Compiler to fine-tune the internal model to provide the expected behavior.
If the source physical data provided for the model is not consistent with the figures of merit (FOMs) provided (meaning the actual FOM values resulting from physical parameters differ from provided FOM data), the model can tune the provided physical data to match the FOMs to the provided values. For more information, see Tuning Active Compact Models.
[[snippet||12116770242323]]
Vpi_Lpi
|
struct with fields described in table below |
Large signal Vpi.Lpi (V-m) of the electrical phase shifter (as explained in the Vpi Data Visualization in photonic model page section) for voltage range described by "ref1" and "ref2" in the struct. |
Each struct above consists of following fields:
Note: The following variables can be provided as a 2x1 matrix if more than one mode is supported.
[[snippet||11653867902995]]
QA
"QA" is a struct with following fields:
[[snippet||12117860577811]]
statistical
"statistical" is a struct with fields below. This struct is optional and is only required for statistical compact models.
Note: To allow CML Compiler to build statistically enabled models, the statistical_parameter_status has to be defined in the XML file. For more information, see Statistical CMLs.
Field | Type | Description |
---|---|---|
parameters |
struct |
Each field of this struct defines one statistical parameter for the model. These fields should have names following "parameter_X" where X is an integer and follow the structure described in statistical parameters table. Note: This data is required for CML Compiler to enable statistical modeling. |
QA |
struct with fields described in QA table |
Defining QA settings for statistical QA. |
statistical parameters
[[snippet||11647965606547]]
slope_neff |
Number
|
The sensitivity of the effective index of the active waveguide with respect to the X-th statistical parameter defined as d_neff / d_parameter_X. Note: Only provide this field if the statistical parameter affects the effective index (see ps_pn_stat_te_c). |
slope_ng |
The sensitivity of the group index of the active waveguide with respect to the X-th statistical parameter defined as d_ng/ d_parameter_X. Note: Only provide this field if the statistical parameter affects the group index (see ps_pn_stat_te_c). |
|
slope_Vpi_Lpi |
The sensitivity of the Vpi_Lpi (V-m) of the electrical phase shifter with respect to the X-th statistical parameter defined as d_Vpi_Lpi/ d_parameter_X. Note: Only provide this field if the statistical parameter affects the Vpi_Lpi (see ps_pn_stat_te_c). |
|
slope_IL |
The sensitivity of the insertion loss (dB) of the electrical phase shifter with respect to the X-th statistical parameter defined as d_IL / d_parameter_X. Note: Only provide this field if the statistical parameter affects the insertion loss (see ps_pn_stat_te_c). |
statistical QA
[[snippet||12118523234707]]