SystemVerilog WDM Simulation Project

This project is a collection of SystemVerilog modules and C++ testbenches for simulating a Wavelength Division Multiplexing (WDM) system with microring resonators. The project uses Verilator to compile the SystemVerilog code into C++ for high-performance simulation.

Project Structure

.
├── cmake/            # CMake helper scripts
├── docs/             # Sphinx documentation
├── lib/              # RTL libraries
│   ├── cpp/
│   └── verilog/
│       ├── circuits/
│       ├── photonics/
│       └── tuner/
├── sim/              # Simulation testbenches
└── src/              # Source files (not extensively used)

RTL Libraries (lib/verilog/)

The lib/verilog/ directory contains the core SystemVerilog modules for the WDM system.

• circuits/: Basic analog and mixed-signal components like ADCs and DACs.
• photonics/: Models for optical components, including:
  • laser.sv: A multi-wavelength laser source.
  • microring.sv: A single microring resonator.
  • microringrow.sv: A row of microring resonators.
  • photodetector.sv: A photodetector to convert optical power to electrical current.
• tuner/: Control logic for tuning the microring resonators.
  • tuner_search_phy.sv: Sweeps the tuning voltage to find resonance peaks.
  • tuner_lock_phy.sv: Locks the microring's resonance to a specific wavelength.

Package compile order is defined in cmake/VerilogPackages.cmake. Adjust this file if additional packages are added or the order needs to change.

Simulation (sim/)

The sim/ directory contains the C++ testbenches for simulating the RTL modules. Each subdirectory is a self-contained simulation environment.

• Each testbench has a dut.sv (Design Under Test) and a tb.cpp (testbench).
• The tb.cpp file drives the simulation, provides inputs to the DUT, and checks the outputs.
• The project uses CMake to build and run the simulations.

Building and Running Simulations

To build the project, you will need to have CMake and Verilator installed. If Verilator is not installed system-wide, set the VERILATOR_ROOT environment variable to point to the Verilator installation directory so CMake can locate it.

1. Create a build directory:

   mkdir build
   cd build

2. Run CMake (setting VERILATOR_ROOT if needed):

   export VERILATOR_ROOT=/opt/verilator  # adjust path to your installation
   cmake ..

3. Build the simulations:

   make

4. Run a specific simulation:

   make run-<simulation_name>

   For example, to run the hello_world simulation:

   make run-hello_world

Requirements

Tested under:

• cmake v3.31.1
• verilator 5.014

Documentation

The project documentation is generated using Sphinx. To build the documentation, navigate to the docs/ directory and run:

make html

The generated HTML documentation will be in the docs/build/html/ directory.