111PNP(c) (d)Si-(e) (f) c d) (e) (f) 21Superstructure-grating DBR lasers (NEL) e-beam low power)31 j ) exp( ) exp( ) ( x iK B x iK A xj j j j = φ j ) (2 1 2 2 20β =j jn k K ) exp( ) exp(1 1 1 =n