The printed circuit board may include an embedded optical waveguide and {HEAD ~ a first optical window} extending from the optical waveguide to {TAIL ~ a first surface} of the printed circuit board 
extending to
The printed circuit board may include an embedded optical waveguide and { HEAD ~ a first optical window } extending from the optical waveguide to { TAIL ~ a first surface } of the printed circuit board
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH