In Fig.10, it is found that the asymmetric MZ interferometer (MZI) shows maximum and
minimum transmission at frequencies 3.816GHz and 4.196GHz, which are indicated by
arrows and dots in the figure. Measurement of symmetrical MZI showed almost flat and
relatively high transmission characteristics over same frequency range, comparing with result
of asymmetrical one. Therefore, simulations by CIP method were demonstrated for these two
frequencies and additional one frequency 4.006GHz as middle level of output.
The electric field profiles by CIP method along with MZI are shown for these three frequencies
in Fig.11. The electric field profile at output port is also indicated in Fig.12. From these figures,
it is found that electric field propagated along with two arms comes to combining point with
relatively small phase difference in Fig.11(a) and (b), while electric field become extinct for
the two fields comes to combining point with out of phase in Fig.11(c) . In Fig.12(c), the
maximum electric field is quite small compared with output with small phase difference in
MZI as shown in Fig.12(a) and (b). From Fig.10 to 12, complicated output characteristics were
qlearly interpreted by numerical results by CIP method. This is because CIP method provides
more precise results of electromagnetic wave scattering compared with FDTD method, as we
saw in subsection 3.1. From these results, it was shown that superiority and significance of the
CIP method for designing photonic crystal structure which is composed of periodic structure
with high contrast of material constant.