FDTD simulation of photonic devices and circuits based on circular and fan-shaped microdisks

This paper proposes novel photonic devices and circuits composed of circular and fan-shaped microdisks. Using the finite difference time domain (FDTD) method, we investigated propagation characteristics of light in fundamental elements, the coupler of closely placed disks and the butt-joint of disks. The coupler can be used for extracting the light from a disk laser. It was shown that the efficiency of the light extraction can be over 70% by the coupler. A mode size converter and a tunable filter combined with couplers were numerically demonstrated. The joint can be applied to a compact and sophisticate optical wiring in a large scale circuit, since the joint loss estimated was as low as 0.1 dB.