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