{HEAD ~ The optical power}, e.g. from {TAIL ~ a high power laser}, is conveyed via an optical fibre to the controlled device 
from
{ HEAD ~ The optical power } , e.g. from { TAIL ~ a high power laser } , is conveyed via an optical fibre to the controlled device
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH