The second optical window may be formed in {HEAD ~ a straight line} with {TAIL ~ an optical input/output section} formed in the memory die and the first optical window 
The second optical window may be formed in { HEAD ~ a straight line } with { TAIL ~ an optical input / output section } formed in the memory die and the first optical window
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH