An electro-optic phase shifter model based on free-carrier plasma dispersion effects, operating in depletion mode. 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.
For an example of how to collect all the modelling data for this template, see the PN Depletion Phase Shifter example in the Application Gallery.
Note: For legacy data format (2022 R2.4 and older) please visit following link:
Electrical Phase Shifter (Reverse Bias) - Lumfoundry Template (Legacy)
Template: ps_pn_te_c (depletion type, lumped electrode), ps_pn_tw_te_c (depletion type, travelling wave electrode)
Photonic Model: phase_shifter_electrical
Quality Assurance Test: phase_shifter_electrical QA
Supported 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 (not for travelling wave models).
Application Gallery Example: PN Depletion Phase Shifter
Modeling Data
The source data template for an Electrical Phase Shifter element can divided into two sections.
- For new users (continue with following session: 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 the 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 the 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 |
Each struct above consists of the 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 the 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 the 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
| 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 elec_eq_ckt_data |
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 the following fields:
Note: The 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 advanced data section provides a complete reference of data supported by the spar-fixed model including the basic required data described in the previous section.
The description of all the fields in the source data template are described below.
general
"general" is a struct with the following fields:
[[snippet||11549514081811]]
ports
"ports" is a struct with the following fields:
[[snippet||12092461714963]]
Each struct above consists of the following fields:
[[snippet||11549759363603]]
parameters
"parameters" is a struct with the following fields:
[[snippet||12092500096659]]
Each struct above consists of the following fields:
[[snippet||11720299494931]]
model_data
"model_data" is a struct with the 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 the 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 the following fields:
Note: The 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 the following fields:
[[snippet||12117860577811]]