Whispering gallery modes (WGMs) in microcavities possess ultra- high cavity Q factor. Such microcavity are easy to be
fabricated, so WGMs have attracted much attention in the area of photonics and integrated photonic circuits. It is well
known that the effect of total internal reflection restricts the size of this mirocavity. Such drawback goes against the
integration of photon. However, the photonic crystal microcavities (PCMC) make a breakthrough recently. The WGMs
in the PCMC are possible to gain both ultra-high Q and ultra-small mode volume. In this paper, the property of the mode
in photonic crystal ring cavity is analyzed by FDTD and PWE. By modifying the airholes in the corners of the ring
cavity, we can obtain the WGM. Also the Q factor of WGM in photonic crystal ring cavity is calculated. This favors the
design of the photonic crystal microcavity components.
In this work, the guided modes of a photonic crystal polarization beam splitter (PC-PBS) are studied. We demonstrate
that the transmission of a low-loss photonic crystal 120° waveguide bend integrated with the PBS will be influenced if
the PBS is multi-moded. We propose a single-moded PC-PBS structure by introducing deformed structures, and it shows
twice the enhancement of the transmission. This device with remarkable improvement of performance is promising in
the use of photonic crystal integrated circuits design.