Theoretical research on high sensitivity gas sensor due to slow light in slotted photonic crystal waveguide

A miniature and sensitivity gas sensor based on slotted photonic crystal waveguide (SPCW) was presented, in which the correlation spectroscopy method was applied for signal processing and the SPCW was used for the gas cell. To enhance the system sensitivity, the structure of the SPCW was optimized to possess extremely high group index and very large light confinement in the slot. Simulation results indicated that the measuring resolution of acetylene gas of 1 ppm was achieved with good temperature stability. Additionally, the active region was only 1 mm long, which could be of great advantage in the use of the limited space.