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