The photodetector_pcell photonic model represents pcell photodetector elements in which the performance is parameterized based on the physical dimensions of the device such as length and width. The model supports bias dependent responsivity and provides the ability to model both shot and thermal noise, as well as saturation effects. Similar to the photodetector_simple photonic model, it also supports the generation of photodetector elements with up to two optical inputs, as well as multiple (up to two) electrical anode ports. The model also supports statistical variation of its figures of merit including dark current, responsivity and bandwidth. For information on statistical CMLs, see Statistical CMLs.
Lumfoundry Templates: Photodetector Pcell, photodetector pcell (statistical)
Quality Assurance Test: photodetector_pcell QA
Statistical Modeling Support: responsivity, bandwidth, dark current
Supported Parameters: Width, Length
Tuning Support: None.
Interoperability with Cadence Virtuoso:
- Circuit design flows using INTERCONNECT model: Yes.
- Circuit design flow using photonic Verilog-A model: Yes.
Model Information
-
This model currently supports thermal noise, shot noise and power saturation for the INTERCONNECT model.
- Shot noise is supported in the Verilog-A model.
Electrical equivalent circuit for photonic Verilog-A model
The photonic Verilog-A model is compatible with Cadence Virtuoso design platform and its Spectre simulator. Electrical bandwidth and loading effect of the parameterized photodetector (PD) element are described by the electrical equivalent circuit for the Verilog-A model. The figure below shows the electrical equivalent circuit for the parameterized PD Verilog-A model, which can be created using CML Compiler GUI with Verilog-A option checked for the selected parameterized PD element.
The circuit parameters are as described in the table below.
Parameter | Description | Unit | Comments |
Cj | Junction capacitance | F |
|
Rj |
Junction resistance |
ohm |
|
Cp |
Parasitic capacitance |
F |
|
Rp |
Parasitic resistance |
ohm |
|
When simulating the photonic Verilog-A parameterized PD model using Spectre, the electrical equivalent circuit and the photonic APD model are implemented inside the compiled photonic Verilog-A parameterized PD model as shown below. Spectre simulates both the electrical equivalent circuit for the parameterized PD’s electrical characteristics and the photonic parameterized PD model for its optical characteristics.