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