Integrated optical Mach-Zehnder interferometer with a sensing arm of sub-wavelength grating waveguide in SOI

An integrated optical Mach-Zehnder interferometer comprised of a sensing arm of sub-wavelength grating waveguide and a reference waveguide arm insensitive to cladding refractive index change has been proposed and demonstrated in silicon-on-insulator platform for lab-on-chip application. The device is designed to operate at an operating wavelength of λ ∼ 1550 nm and its sensitivity is estimated as high as ∼ 931 rad/RIU/mm, which is again linearly scalable with the sensing length.