The mach_zehnder_modulator_2x2 photonic model is specifically tailored to Mach-Zehnder modulators (or passive Mach-Zehnder interferometers and thermo-optic switches) with 2 optical inputs and 2 optical outputs. It provides the ability to model 2x2 Mach-Zehnder modulators with either travelling wave electrodes, or lumped-model electrodes, and allows parameterization of overall modulator length, as well as imbalance length.
The mach_zehnder_modulator_2x2 photonic model supports statistical modeling. Users can choose an arbitrary number of statistical parameters and define their influence on the effective and group index of the active waveguide as well as the figure of merits such as insertion loss, free-spectral range, electrical bandwidth, voltage for pi phase shift (Vpi) of the modulator, and power for pi phase shift (Ppi) for the thermal tuner. For information on statistical CMLs, see Statistical CMLs.
Lumfoundry Templates: Mach-Zehnder Modulator 2x2, Mach-Zehnder Modulator 2x2 (Statistical), Mach-Zehnder Interferometer 2x2 (thermally tuned), Thermal Switch 2x2, Thermal Switch 2x2 (statistical)
Quality Assurance Test: mach_zehnder_modulator QA
Statistical Modeling Support: neff (active), ng (active), resonant_wavelength, FSR, ER, IL, Vpi_electrical (MZM only), electrical_bandwidth (MZM only), Ppi_thermal.
Supported Parameters: phase shifter length (MZM), Thermal tuner length (thermal switch), imbalance length
Tuning Support:
Unbalanced: Free Spectral Range (FSR), insertion loss, extinction ratio, resonant wavelength, electrical and thermal modulation efficiency (if applicable)
Balanced: electrical and thermal modulation efficiency (if applicable).
Interoperability with Cadence Virtuoso:
- Circuit design flows using INTERCONNECT model: Yes.
- Circuit design flow using photonic Verilog-A model: No.
Advanced Options
The model is very versatile, and has several different options that can be enabled or disabled using different parameters included in the model data requirement. To see the list of data requirement please visit lumfoundry template pages.
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Balanced/unbalanced model |
Balanced: default_imbalance_length equals to zero Unbalanced: default_imbalance_length has none zero value |
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Modulator/interferometer/thermal switch model |
Modulator: Electrical phase shifter relays exist Interferometer: Electrical phase shifter relays do not exist Thermal switch: Electrical phase shifter relays do not exist |
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Enable/disable thermally tuned model |
Enable: Thermal tuner relays exists Disable Thermal tuner relays do not exist |
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Travelling wave/lumped model (electrical phase shifter) |
Travelling wave model: use_travelling_wave_electrode= True Lumped model: use_travelling_wave_electrode= False |
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Statistical/nominal model |
Statistical model: stat_parameters exist Nominal model: stat_parameters does not exist |
Model Information
- Internal Model Diagram:
- Spectrum Data Visualization:
The following figure shows how to obtain IL, ER_V1, ER_V2, ER_V1_voltage, and ER_V2_voltage from the transmission spectra of an unbalanced MZM.
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Vpi Data Visualization:
Vpi_electrical_voltage1 and Vpi_electrical_voltage2 describe the endpoints of the region for which the electrical phase-shifter Vpi measurement was done.
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Electrical Equivalent Circuit:
When a lumped model is used for the phase shifter (the alternative to a travelling wave model), the bandwidth of the electrical phase shifter is achieved by including an electrical equivalent circuit on each arm:
- This model assumes thermal bandwidth to be constant over all bias range
- This model only supports single mode operation
- User can disable electrical equivalent using the 'internal electrical equivalent' flag.
- Models offers delay compensation for both internal circuit (to compensate group delay for building block elements of the model) and external circuit (to compensate group delay for any element externally connected to the model). For more information on delay compensation please see Delay Compensation in Transient Sample Mode Time-Domain Simulations.