a receiver module disposed within the receiver module housing, the receiver module having an optical to electrical converter for converting optical signals into electrical signals, wherein {HEAD ~ at least a portion} of the optical signal propagating along the tube toward the second end of the tube passes out of the second end of the tube and is optically coupled onto {TAIL ~ the OEC} 
is optically coupled onto
a receiver module disposed within the receiver module housing , the receiver module having an optical to electrical converter for converting optical signals into electrical signals , wherein { HEAD ~ at least a portion } of the optical signal propagating along the tube toward the second end of the tube passes out of the second end of the tube and is optically coupled onto { TAIL ~ the OEC }
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 HEAD HEAD 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 REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL