Towards optical fluorescence sensing using multimode interference splitters

One to N MMI splitters suitable for use in optical sensors have been fabricated using electron beam irradiation of germanium doped flame hydrolysis deposited (FHD) silica (a technique that we have previously used for producing waveguides) (Garcia-Blanco et al., 2001). The splitters have been integrated with microfluidic chambers to form a direct-excitation fluorescence sensor chip for use at visible wavelengths.