Dispersive optical bistability in one-dimensional doped photonic band gap structures

We introduce a Kerr-type nonlinear defect layer in the center of one-dimensional. photonic band gap structure. For linear parts, we use transfer matrix technique, and for the nonlinear layer, we solve the Maxwell equation numerically. When incident light intensity varies, a typical S-shape curve of the transmitted light intensity is obtained. In this case, an optical bistability is produced by dynamic shifting of the defect mode frequency, not dynamic shifting of the band edge, which is different from the case of periodic nonlinear superlattices. It is also found that when the linear defect mode frequency moves from the center of the gap to the edge of the gap, the threshold intensity needed for the bistability increases rapidly.