Abstract
For realizing compact infrared absorption sensing device, a gas-cell-utilizing optical waveguide is attractive due to the possibility of long optical path integration. We propose a novel strip high-mesa waveguide for infrared absorption sensing for the first time. The higher optical power portion out of the waveguide (we define this portion as "Γair") is the key feature for the infrared absorption. We show that the novel waveguide realizes Γair as high as 71% at the wavelength of 1550 nm. An extremely small bending radius below 10 µm has also been confirmed theoretically.