A Mach-Zehnder modulator model, supporting multiple parameters as well as travelling wave electrodes.
Phase shifter length and imbalance length can be parameterized for this unbalanced MZM model.
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Mach-Zehnder Modulator - Lumfoundry Template
Template: mzm_unbalanced_te_c (Lumped model), mzm_unbalanced_tw_te_c (Travelling wave), mzm_balanced_te_c
Photonic Model: mach_zehnder_modulator
Quality Assurance Test: mach_zehnder_modulator QA
Parameters: phase shifter length, imbalance length
Virtuoso/Verilog-A Support: Yes (not for travelling wave models)
Required Data
The photonic model used in these templates allows the creation of compact models with either a travelling wave electrode model or a lumped electrode model. Lumped electrode structures usually have shorter length (in um range) and travelling wave structures have longer lengths (in the order of mm). The velocity mismatch between the RF electrical signal and the optical signal in the waveguide has to be accounted for in a travelling wave structure. Depending on the model type used, either the data within the Lumped Model or Travelling Wave Electrode section must be provided.
Parameter Script File
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QA Variables
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Data File
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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 a setting within the parameter .lsf file:
use_travelling_wave_electrode = true;
Lumped Model
This data will only be used if the travelling wave electrode is disabled within the parameter LSF file, which is done by setting the use_travelling_wave_electrode setting to false. The data within this section is used to construct an electrical equivalent circuit which captures the bandwidth of the electrical phase shifters. For more information on this equivalent circuit, 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:
|
Rj |
Number |
Junction resistance (\(\Omega \cdot m\)) of the phase shifter |
Rp |
Number |
Contact resistance (\(\Omega)\) of the metal pad |
Cp |
Number |
Parasitic capacitance (F) between metal pads |
Travelling Wave Electrode
This data will only be used if the travelling wave electrode is enabled within the parameter LSF file, which is done by setting the use_travelling_wave_electrode setting to true.
Note: These 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 (\(\Omega\)) of the traveling wave electrode | |
X0 | Characteristic reactance (\(\Omega\)) of the traveling wave electrode | |
Rs | Source resistance (\(\Omega\)) for the traveling wave electrode model | |
Xs | Source reactance (\(\Omega\)) for the traveling wave electrode model | |
Rj | Junction resistance (\(\Omega \cdot m\)) of the electrical phase shifter | |
n_RF | Microwave index of the traveling wave electrode | |
Rl_top | Terminating resistance (\(\Omega\)) of the top electrode | |
Xl_top | Terminating reactance (\(\Omega\)) of the top electrode | |
Rl_bottom | Terminating resistance (\(\Omega\)) of the bottom electrode | |
Xl_bottom | Terminating reactance (\(\Omega\)) of the bottom electrode | |
Cj | Matrix | N x 2 matrix containing the junction capacitance (F/m) of the electrical phase shifter, where N is the number of bias voltages, and the columns contain:
|
Related Publications
- Hao Xu et al., "Demonstration and Characterization of High-Speed Silicon Depletion-Mode Mach–Zehnder Modulators", IEEE Journal of Selected Topics in Quantum Electronics, Vol. 20, No. 4 (2014)