The method 6 wherein {TAIL ~ the predetermined characteristic} is a predetermined range of power levels for {HEAD ~ the fiber optic signal} 
The method 6 wherein { TAIL ~ the predetermined characteristic } is a predetermined range of power levels for { HEAD ~ the fiber optic signal }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD