In {HEAD ~ a preferred form}, the present invention provides a balanced non blocking switch by using symmetrical configurations of optically coupled GMZIs, and also provides a cascaded non blocking switch by cascading an N×N GMZI with {TAIL ~ a × non blocking switch} 
In { HEAD ~ a preferred form } , the present invention provides a balanced non blocking switch by using symmetrical configurations of optically coupled GMZIs , and also provides a cascaded non blocking switch by cascading an N×N GMZI with { TAIL ~ a × non blocking switch }
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL