{HEAD ~ A transparent chip substrate} or appropriate holes within the substrate would allow {TAIL ~ the external optical devices} to be positioned within the semispherical volume beneath the chip 
allow
{ HEAD ~ A transparent chip substrate } or appropriate holes within the substrate would allow { TAIL ~ the external optical devices } to be positioned within the semispherical volume beneath the chip
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH