A statistically enabled photodetector model. The statistical parameters are responsivity, electro-optic bandwidth and dark current.
For an example of how to extract nominal parameters in INTERCONNECT, see Vertical Photodetector. For information on statistical CMLs, see Statistical CMLs.
Note: For legacy data format (2022 R2.4 and older) please visit following link:
Photodetector (Statistical) - Lumfoundry Template (Legacy)
Template: pd_stat_c
Photonic Model: photodetector_simple
Quality Assurance Test: photodetector_simple QA
Parameters: None
Statistically Enabled Parameters: responsivity, bandwidth, dark current.
nteroperability 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 photodetector 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 )
The photodetector template can be used to create a very advanced compact model for a custom photodetector. The template contains a lot of different modeling data to create an accurate model. However, not all these data need to be updated by the user. The fastest/ simplest way to modify the template data and create a custom compact model would be to only update the values of the data listed in the 'basic data requirement section' below, while all rest of the data (which is illustrated in detail in subsequent sections) can be left at their default value.
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 photodetector 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 that provides 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 input optical port |
ele_an |
Port definition corresponding to the anode and cathode of the photodetector. |
|
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 at which the port is listed in a netlist. |
model_data
"model_data" is a struct with following fields:
Field | Type | Description |
---|---|---|
bandwidth_data
|
struct
|
The 3-dB cutoff frequency (Hz) of the photodetector as a function of applied bias voltage (V). The required fields are:
Note: Data must be provided for at least two bias voltages |
Idark_data
|
struct
|
The total dark current (A) of the photodetector as a function of bias voltage (V). The required fields are:
Note:
|
resp_data
|
struct |
The responsivity (A/W) of the photodetector as a function of frequency (Hz). The required fields are:
Notes:
|
elec_eq_ckt_data (optional)
|
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 Electrical equivalent circuit details in the photonic model page. |
elec_eq_ckt_data
Field | Type | Description |
---|---|---|
Rj |
number |
Series resistance (Ω) of the photodetector. |
Cj_data |
number/matrix |
Junction capacitance (F) of the photodetector, provided in either one of the following forms: 1. A single value containing the the junction capacitance. 2. An struct containing junction capacitance as a function of bias voltage, and the required fields are:
|
Rp |
number |
Parasitic contact resistance (Ω) of the photodetector |
Cp |
number |
Parasitic capacitance (F) from the metal pads |
Complete data requirement (for advanced users)
The complete data section provides a complete reference of data supported by the photodetector model including the basic required data described in the previous section. The description of all the fields in the photodetector 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||12153503240467]]
opt_2 (optional) |
struct with fields described in table below |
Port definition corresponding to the second input optical port |
ele_an_2 (optional) |
Port definition corresponding to the second anode of the photodetector. |
Each struct above consists of following fields:
[[snippet||11549759363603]]
parameters
"parameters" is a struct with following fields:
[[snippet||12153804332691]]
Each struct above consists of following fields:
[[snippet||11720299494931]]
model_data
"model_data" is a struct with following fields:
[[snippet||12154138198803]]
[[snippet||12157844950675]]
QA
"QA" is a struct with following fields:
[[snippet||12155371687955]]
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_Resp |
number |
The sensitivity of the responsivity of the photodetector with respect to the X-th statistical parameter defined as d_Resp / d_parameter_X. Note: Only provide this field if the statistical parameter affects the responsivity (see pd_stat_c). |
slope_BW |
number |
The sensitivity of the electro-optic bandwidth of the photoetector with respect to the X-th statistical parameter defined as d_BW / d_parameter_X. Note: Only provide this field if the statistical parameter affects the bandwidth (see pd_stat_c). |
slope_Idark |
number |
The sensitivity of the dark current of the photoetector with respect to the X-th statistical parameter defined as d_Idark / d_parameter_X. This perturbation will be applied uniformly for all bias voltages; hence the slope should be provided for the default/typical operating bias of the photodetector.
Note: Only provide this field if the statistical parameter affects the dark current (see pd_stat_c). |
statistical QA
[[snippet||12156461004947]]
VA_reference_data_available
|
boolean | When true, Verilog-A statistical QA results will be compared against reference data of Verilog-A simulation. When false, reference data is generated (only needed for the first run or after a model update). |
VA_N_trials | number | Number of trials in Monte Carlo sweep for Verilog-A |
parameters | struct |
Parameter values used for setting up the QA test bench. The required field is:
|