{TAIL ~ The waveguide portion} also has a third circular arc optical waveguide portion extending from {HEAD ~ a first splitting/coupling point side} in the first circular arc waveguide portion toward the plural/ports side and having a curvature inverted relative to the first circular arc optical waveguide portion 
{ TAIL ~ The waveguide portion } also has a third circular arc optical waveguide portion extending from { HEAD ~ a first splitting / coupling point side } in the first circular arc waveguide portion toward the plural / ports side and having a curvature inverted relative to the first circular arc optical waveguide portion
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH