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