Anewgratingstructurewithcladdingetchedasthesinusoidalfunctionalongthelengthdirectionisintroduced.Thecladdingareaofthegratingvariesasthesinusoidalfunctionalongfiberaxes.Thecoupledmodetheoryisusedtoanalyzeitsperformance.Comparedwiththelinearlychirpedgrating,thenewstructureexhibitsanidealboxspectrumwithsteepedgeswhenthetensionisappliedonthegratingsintwodifferentways.ForthetypeBgrating,withouttensionafterwriting,ithasabiggerbandwidthutilization(BWU)thanthatofthetypeAgratingwithtensionafterwriting.ComparedwiththetypeAgrating,thetypeBoneismoreadaptableinfiber-opticcommunicationsandsensorsystems.
