Novel Design of Current Driven Photonic Crystal Laser Diode

Contrary to the great possibilities of photonic crystal (PC), a practical laser diode with a PC cavity has not yet been developed. This is mainly due to the lack of electrically driven devices; Since a two-dimensional PC slab cladded by air is often employed to realize strong light confinement, it is difficult to inject carriers into a cavity in such an air-bridge structure. An electrically driven laser using a tiny semiconductor pillar for current injection has been reported; however, a large cross-section of the pillar (or low electrical resistance) trades-off a large $Q$-factor sufficient for lasing. In this letter, we propose a novel design of PC laser diode in which light confinement and carrier injection are highly compatible.