{HEAD ~ a laser} optically coupled to said first light input via a first optical fiber and optically coupled to said second light input via {TAIL ~ a second optical fiber} 
{ HEAD ~ a laser } optically coupled to said first light input via a first optical fiber and optically coupled to said second light input via { TAIL ~ a second optical fiber }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL