fix(tidy3d): FXC-5313 improve broadband frequency range warning message

Author: weiliangjin2021

tests/test_components/test_source.py

@@ -133,7 +133,7 @@ def test_gaussian_from_frequency_range():
     g2 = td.GaussianPulse.from_frequency_range(fmin=fmin, fmax=fmax)
     assert g2.remove_dc_component
 
-    with AssertLogLevel("WARNING", contains_str="not sufficiently large"):
+    with AssertLogLevel("WARNING", contains_str="broadband"):
         g_small = td.GaussianPulse.from_frequency_range(
             fmin=fmin, fmax=60e9, remove_dc_component=True
         )

tidy3d/components/source/time.py

@@ -389,8 +389,8 @@ def from_frequency_range(
         pulse = cls(freq0=freq0, fwidth=fwidth, **kwargs)
         if np.abs(pulse._rel_amp_freq(fmin)) < WARN_SOURCE_AMPLITUDE:
             log.warning(
-                "Source amplitude is not sufficiently large throughout the specified frequency range, "
-                "which can result in inaccurate simulation results. Please decrease the frequency range.",
+                "Default source time profile is less accurate for the specified broadband frequency range. "
+                "For more accurate results, consider reducing the frequency range or using a 'BroadbandSource'.",
             )
         return pulse