The electro-absorption_modulator model can be used to create compact models for field-effect modulators using Franz-Keldysh effect or Kerr effect. The model supports temperature dependency and photocurrent modeling.
Lumfoundry Templates: Electro-absorption Modulator
Quality Assurance Test: electro_absorption_modulator QA
Statistical Modeling Support: None
Supported Parameters: None
Tuning Support: IL, ER
Interoperability with Cadence Virtuoso:
- Circuit design flows using INTERCONNECT model: Yes.
- Circuit design flow using photonic Verilog-A model: Yes.
Model Information
- This model assumes that the effect of temperature on IL is identical for all bias voltages.
- This model assumes that the effect of temperature on photocurrent is identical for all bias voltages.
- The above two assumptions allow the effect of bias and effect of temperature to be decoupled in the model.
- This model neglects any interference of light inside the modulator if light comes from both optical ports simultaneously.
- This model does not support delay compensation.
- Electrical Equivalent Circuit
Electrical Equivalent Circuit INTERCONNECT model
The INTERCONNECT model can be used in the Cadence Virtuoso platform for PIC (photonic integrated circuits) and EIC (electronic integrated circuits) co-design and co-simulation. Electrical bandwidth of the electro-absorption modulator is defined by an electrical low pass filter (LPF) inside INTERCONNECT optical model. When running a Spectre-INTERCONNECT co-simulation, the electrical bandwidth and loading effect of the modulator can be alternatively described by an electrical equivalent circuit, which is physically instantiated in Spectre, and in this case the LPF inside INTERCONNECT optical model must be turned off to avoid double counting the modulator’s electrical bandwidth.
This section describes the use of electrical equivalent circuit for Spectre-INTERCONNECT co-simulation case. The below figure shows the schematic of the electrical equivalent circuit for the electro-absorption modulator, which can be created by running CML Compiler with the “--interconnect_virtuoso” command line option.
Parameter | Description | Unit | Comments |
Cj |
Junction capacitance |
F |
|
Rj |
Junction resistance |
ohm |
|
Cp |
Parasitic capacitance |
F |
|
Rp |
Contact resistance |
ohm |
|
The figure below shows the use of the electrical equivalent circuit and the optical INTERCONNECT model (i.e., EAM_O) for co-simulation case. The voltage Cj is used to drive the optical INTERCONNECT model. For co-simulation, Spectre simulates the electrical equivalent circuit for its electrical bandwidth and loading effect, while INTERCONNECT simulates the optical INTERCONNECT model. In this case, the internal electrical LPF of the optical INTERCONNECT model must be turned off to avoid double counting the modulator’s electrical bandwidth.
Electrical equivalent circuit for Photonic Verilog-A model
The photonic Verilog-A model is compatible with Cadence Virtuoso design platform and its Spectre simulator. When simulating the photonic Verilog-A model for an electro-optic modulator (EAM) element using Spectre, the electrical equivalent circuit model and the photonic model are both implemented inside the compiled Verilog-A EAM element as shown in the figure below. Spectre simulates both the electrical equivalent circuit for the EAM’s electrical characteristics and the photonic EAM model for its optical characteristics. The Verilog-A model for an EAM element can be generated through CMLC by executing it with --veriloga_virtuoso command line option.