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.
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Electrical Phase Shifter (Reverse Bias) - Lumfoundry Template
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
Virtuoso/Verilog-A Support: Yes (not for travelling wave models).
Application Gallery Example:PN Depletion Phase Shifter
Required Data
This template allows for the creation of compact models operating under reverse bias (depletion type) with either a travelling wave electrode model or a lumped electrode model. All models require the data within the table below. Depending on the model type used, either the data within the Lumped Model or Travelling Wave Electrode section must be provided.
Parameter Script File
[[snippet||7228384629395]]
lock_Vpi_Lpi |
Boolean |
Enable/disable tuning of the Vpi_Lpi (V-m) of the phase shifter. Note: locking Vpi-Lpi is not available for Verilog-A model. |
QA Variables
[[snippet||7227146485523]]
Vpi_Lpi_rel_tolerance | Number |
Relative tolerance for QA tests which verify the model properties. If the simulated values differ from the values provided within the data file by more than this tolerance, the QA tests will fail. |
* Note: BW_test_bias is typically set at half Vpi of the phase shifter with default length.
Data File
[[snippet||7229114568851]]
electrical_bandwidth_data |
Matrix |
N x 2 matrix containing the 3-dB cutoff frequency (Hz) of the electrical modulator as a function of bias voltage (V), where N is the number of bias points, and the columns contain:
Notes:
|
phase_shifter_data |
Cell |
M x 1 cell array containing structs which describe the variation of the effective index within the active region, as a function of bias voltage (V). Each element of the cell array is a struct containing the following fields:
Notes:
|
Model Tuning & QA Data
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.
Variable | Type | Description |
---|---|---|
IL |
Struct
|
The total insertion loss (dB) of the phase shifter at zero bias provided as a struct. The struct has the following fields:
Notes:
|
Vpi_Lpi |
Large signal Vpi.Lpi (V-m) of the electrical phase shifter (as explained in the Vpi Data Visualization in photonic model page section) for voltages between Vpi_Lpi_voltage1 and Vpi_Lpi_voltage2 provided as a struct. The struct has the following fields:
Notes:
|
|
Vpi_Lpi_voltage1 |
Matrix
|
M x 1 matrix containing the lower limit of the bias voltage for which the Vpi_Lpi values are valid, where M is the number of modes. |
Vpi_Lpi_voltage2 |
M x 1 matrix containing the upper limit of the bias voltage for which the Vpi_Lpi values are valid, where M is the number of modes. |
Electrical Phase Shifter Data
In order to model 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 (see Port Definitions section above).
Lumped Model Electrical Parameters
This data will only be used if the travelling wave electrode is disabled within the parameter .lsf file, which is done by not including the electrical termination port (ele_term_RELAY). 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 electrical_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.
Variable | Type | Description |
---|---|---|
Cj |
Matrix |
N x 2 matrix containing the junction capacitance (F/m) of the electrical phase shifter, where N is the number of bias points, and the columns contain:
Notes:
|
Rj |
Number
|
Junction resistance (Ohm.m) of the phase shifter |
Rp |
Contact resistance (Ohm) of the metal pad |
|
Cp |
Parasitic capacitance (F) between metal pads |
Travelling Wave Electrode Electrical Parameters
This data will only be used if the travelling wave electrode is enabled within the parameter .lsf file, which is done by including the electrical termination port (ele_term_RELAY).
Note: The travelling wave parameters will not be used for Verilog-A models.
Variable | Type | Description |
---|---|---|
loss_RF |
Number
|
Microwave loss (dB/m) of the travelling wave electrode. |
f0_RF |
Central RF frequency of operation (Hz) |
|
R0 |
Characteristic resistance (Ohm) of the traveling wave electrode |
|
X0 |
Characteristic reactance (Ohm) of the traveling wave electrode |
|
Rs |
Source resistance (Ohm) for the traveling wave electrode model |
|
Xs |
Source reactance (Ohm) for the traveling wave electrode model |
|
Cj |
Matrix |
N x 2 matrix containing the junction capacitance (F/m) of the electrical phase shifter, where N is the number of bias points, and the columns contain:
Notes:
|
Rj |
Number
|
Junction resistance (Ohm.m) of the electrical phase shifter |
n_RF |
Microwave index of the traveling wave electrode |
|
Rl_top |
Terminating resistance (Ohm) of the top electrode |
|
Xl_top |
Terminating reactance (Ohm) of the top electrode |
|
Rl_bottom |
Terminating resistance (Ohm) of the bottom electrode |
|
Xl_bottom |
Terminating reactance (Ohm) of the bottom electrode |