{HEAD ~ The third optical waveguide} is formed of {TAIL ~ a multi mode optical fiber} and transmits the multi mode optical signal output from the second optical waveguide 
is formed of
{ HEAD ~ The third optical waveguide } is formed of { TAIL ~ a multi mode optical fiber } and transmits the multi mode optical signal output from the second optical waveguide
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH