The second optical waveguide converts {HEAD ~ the single mode optical signal output} from {TAIL ~ the first optical waveguide} to a multi mode optical signal and allows the optical power of the single mode optical signal to be coupled to each mode of the multi mode optical signal 
The second optical waveguide converts { HEAD ~ the single mode optical signal output } from { TAIL ~ the first optical waveguide } to a multi mode optical signal and allows the optical power of the single mode optical signal to be coupled to each mode of the multi mode optical signal
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH