In sum, the total time that it takes {TAIL ~ the optical signal} to travel from the input element to the output element depends on {HEAD ~ its wavelength} 
In sum , the total time that it takes { TAIL ~ the optical signal } to travel from the input element to the output element depends on { HEAD ~ its wavelength }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD