The time delay unit includes {TAIL ~ a dispersive element} for reflecting the optical signal at an angle that is a function of the wavelength of {HEAD ~ the optical signal} 
The time delay unit includes { TAIL ~ a dispersive element } for reflecting the optical signal at an angle that is a function of the wavelength of { HEAD ~ the optical signal }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD