In this way {HEAD ~ the total optical path length} of the signal in {TAIL ~ the time delay unit} depends on its optical wavelength 
in
In this way { HEAD ~ the total optical path length } of the signal in { TAIL ~ the time delay unit } depends on its optical wavelength
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH