教程43给出了画渐变圆弧型波导的实现方式，这篇教程介绍通过InterpolatedWaveguideTemplate更简单地实现方式：
from si_fab import all as pdk
from ipkiss3 import all as i3
from circuit.waveguides.tapered.waveguide import InterpolatedWaveguideTemplate
shape=i3.ShapeArc(radius=20,start_angle=0,end_angle=90,start_face_angle=90,end_face_angle=180)
tt1 = pdk.SiWireWaveguideTemplate()
tt1.Layout(core_width=3.0)
tt2 = pdk.SiWireWaveguideTemplate()
tt2.Layout(core_width=0.5)
itt = InterpolatedWaveguideTemplate(trace_template_start=tt1, trace_template_end=tt2)
wav = i3.RoundedWaveguide(trace_template=itt)
lv = wav.Layout(shape=shape)
lv.visualize()
