The present invention concerns {HEAD ~ a multi wavelength selective switch} in {TAIL ~ the form} of a directional coupler structure 
The present invention concerns { HEAD ~ a multi wavelength selective switch } in { TAIL ~ the form } of a directional coupler structure
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH