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Quick Start

PhotonForge Quick Start overview

In this quick start, we will show you how to:

  • Load a foundry Process Design Kit (PDK) in PhotonForge
  • Load PDK components
  • Run FDTD simulation by converting 2D layout files to 3D for electromagnetic simulations in a single line of code

Step 1: Loading a Foundry PDK

Start by importing numpy, photonforge, and siepic pdk library:

In [1]:
import numpy as np
import photonforge as pf
import siepic_forge as siepic_pdk

Select the open source ebeam process node, also called the technology stack:

In [2]:
# load the technology and set it as the default
technology = siepic_pdk.ebeam()
pf.config.default_technology = technology

You can inspect the technology object to see all the layer definitions, extrusion specs, port types, and background medium:

In [3]:
technology
Out [3]:
Name: SiEPIC EBeam  |  Version: 0.4.32 The technology object includes layer definitions (Si, SiN, metals, etc.), extrusion specifications for 3D geometry generation, port type definitions for optical waveguides, and background medium settings.

You can also inspect the technology's random variables for process variation analysis:

In [4]:
technology.random_variables
Out [4]:
[RandomVariable('si_thickness', **{'value': 0.22, 'stdev': 0.0037166666666666667}),
 RandomVariable('bottom_oxide_thickness', **{'value': 3.017, 'stdev': 0.001})]

Step 2: Loading Foundry Provided PDK Components

Load a component from the PDK library:

In [5]:
cross = siepic_pdk.component("crossing_horizontal")
cross
Out [5]:
Crossing horizontal component layout

Check the component's simulation models:

In [6]:
cross.models
Out [6]:
{'Tidy3D': Tidy3DModel(run_time=None, medium=None, symmetry=(0, 0, 0),
  boundary_spec=None, monitors=(), structures=(), grid_spec=None,
  shutoff=None, subpixel=None, courant=None,
  port_symmetries=[
    ('P0', 'P1', {'P1': 'P0', 'P2': 'P3', 'P3': 'P2'}),
    ('P0', 'P2', {'P1': 'P3', 'P2': 'P0', 'P3': 'P1'}),
    ('P0', 'P3', {'P1': 'P2', 'P2': 'P1', 'P3': 'P0'})
  ],
  bounds=((None, None, None), (None, None, None)),
  source_gap=None, simulation_updates={}, verbose=True)}

Step 3: Convert 2D Layout Files to 3D for Electromagnetic Simulations

Run a 3D FDTD simulation to compute the S-matrix:

In [7]:
# run 3D FDTD simulation to compute s_matrix
wavelengths = np.linspace(1.535, 1.565, 20)
s_matrix = cross.s_matrix(frequencies=pf.C_0 / wavelengths)
Loading cached simulation from .tidy3d/pf_cache/PGK/fdtd_info-QTFDG...json.
Progress: 100%

Visualize the S-matrix results:

In [8]:
plt = pf.plot_s_matrix(s_matrix, y="dB", input_ports=["P0"], output_ports=["P3"])
Out [8]:
S-matrix plot showing transmission in dB

Want to learn more?

Download the full Jupyter notebook from the PhotonForge documentation or explore the example library for more tutorials.