The second optical waveguide converts the single mode optical signal output from 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 {HEAD ~ each mode} of {TAIL ~ the multi mode optical signal} 
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The second optical waveguide converts the single mode optical signal output from 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 { HEAD ~ each mode } of { TAIL ~ the multi mode optical signal }
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 OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL