convergence testing examples

examples/04_import_technology/04b_convergence_sbend.py

@@ -0,0 +1,80 @@
+# %%!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+convergence testing examples using an unideal S-bend test case. 
+@author: Mustafa Hammood
+"""
+import gds_tidy3d as gtd
+import tidy3d as td
+import os
+import matplotlib.pyplot as plt
+import numpy as np
+
+def convergence_z_span(
+    layout: gtd.core.layout,
+    tech: dict,
+    z_span: list=np.logspace(np.log10(0.221), np.log10(2), num=12)):
+
+    sims_z_span = []
+    sims = []
+
+    for z in z_span:
+        device = gtd.simprocessor.load_component_from_tech(ly=layout, tech=technology, z_span=z)
+        sims.append(gtd.simprocessor.build_sim_from_tech(
+            tech=technology,
+            layout=layout,
+            in_port=0,
+            wavl_min=1.545,
+            wavl_max=1.555,
+            wavl_pts=51,
+            mode_index=[0,1],
+            num_modes=2,
+            symmetry=(
+                0,
+                0,
+                0,
+            ),  # ensure structure is symmetric across symmetry axis before triggering this!
+            z_span=z,
+        ))
+
+        sims[-1].upload()
+        # run the simulation. CHECK THE SIMULATION IN THE UI BEFORE RUNNING!
+        sims[-1].execute()
+        #  visualize the results
+        #sims[-1].visualize_results()     
+
+    fig, ax = plt.subplots()
+    te_log = []
+    tm_log = []
+    s12_te = 'S12_idx00'
+    s12_tm = 'S12_idx11'
+    for idx, sim in enumerate(sims):
+        s_te = sim.s_parameters.S[s12_te].s
+        s_tm = sim.s_parameters.S[s12_tm].s
+        f = sim.s_parameters.S[s12_te].freq
+        te_log.append(10*np.log10(np.abs(s_te[len(s_te) // 2])**2))  # middle
+        tm_log.append(10*np.log10(np.abs(s_tm[len(s_tm) // 2])**2))  # middle  entry        ax.plot(z_span, te_log, 'x-', label="TE", color='b')
+    ax.plot(z_span, te_log, 'x-', label="TE", color='r')
+    ax.plot(z_span, tm_log, 'x-', label="TM", color='r')
+    ax.legend()
+    ax.set_xlabel('z_span [um]')
+    ax.set_ylabel(f'Transmission [dB]')
+
+    return sims
+
+
+if __name__ == "__main__":
+
+    tech_path = os.path.join(os.path.dirname(__file__), "tech.yaml")
+    technology = gtd.core.parse_yaml_tech(tech_path)
+
+    file_gds = os.path.join(os.path.dirname(__file__), "sbend.gds")
+
+    layout = gtd.lyprocessor.load_layout(file_gds)
+
+    # log sampling space, i expect output transission to be log too..
+    z_span_sweep = convergence_z_span(
+        layout=layout,
+        tech=technology,
+        z_span=np.logspace(np.log10(0.221), np.log10(2), num=12),
+        )

gds_tidy3d/core.py

@@ -7,8 +7,6 @@
 
 import tidy3d as td
 import logging
-import numpy as np
-import matplotlib.pyplot as plt
 import os
 
 
@@ -294,7 +292,7 @@ def measure_transmission(
                             idx_out=get_port_name(monitor.name),
                             mode_in=sim_job["source"].mode_index,
                             mode_out=mode,
-                            freq=td.C_0 / (wavl*1e-6),  # convert back to SI. (m)
+                            freq=td.C_0 / (wavl),
                             s=amp,
                         )
                     )
@@ -360,7 +358,7 @@ def plot(self):
             logging.info("Mode amplitudes in each port: \n")
             mag = [10 * np.log10(abs(i) ** 2) for i in i.s]
             phase = [np.angle(i) ** 2 for i in i.s]
-            ax.plot(td.C_0 / i.freq, mag, label=i.label)
+            ax.plot(1e6 * td.C_0 / i.freq, mag, label=i.label)
         ax.legend()
         return fig, ax
 
@@ -378,8 +376,10 @@ def __init__(self, idx_in, idx_out, mode_in, mode_out, freq, s):
     def label(self):
         return f"S{self.idx_out}{self.idx_in}_idx{self.mode_out}{self.mode_in}"
 
-    def plot_freq_vs_s(self):
-        plt.plot(np.array(self.freq)/(1e-6*td.C_0), 10*np.log10(self.s**2))
+    def plot(self):
+        import numpy as np
+        import matplotlib.pyplot as plt
+        plt.plot((1e-6*td.C_0)/np.array(self.freq), 10*np.log10(self.s**2))
         plt.xlabel('Wavelength [um]')
         plt.ylabel('Transmission [dB]')
         plt.title('Frequency vs S')