Mode-hop-free photonic crystal laser fabricated by holographic exposure technology

A mode-hop-free single-mode laser with a two-dimensional photonic crystal was demonstrated. In the device, the photonic crystal was realized by double holographic exposure technology. This novel procedure simplifies the fabrication of such structures greatly. The design of a reverse junction in the photonic crystal layer induces a partial gain coupling into the laser, which could break the symmetry of the transmission spectrum and realize stable single-mode lasing of the laser. The fabricated device has a high single-mode stability and side-mode suppression ratio of over 45 dB without mode hop at a relatively wide injected current range. The measurement results indicate that the laser with a simple fabrication process is promising as a stable single-mode and high-power light source in optical communication systems.