Development of a multichannel integrated interferometer immunosensor

This report describes the design, realization and testing of a highly sensitive two-channel integrated optical (IO) Young interferometer (YI) as well as the design of a first multichannel YI. An integrated channel waveguide Y-splitter with two output parallel branches has been used as the basic optical component for building the YI. The generated interference pattern as result of the overlap of outgoing divergent beams is recorded by a CCD camera and is further analyzed by a computer program based on a Fast Fourier Transformation (FFT) algorithm. The integrated waveguide structure is fabricated in SiON technology. For testing the realized device the refractive indices of several glucose solutions have been measured. The realized sensor shows a phase resolution of ∼1×10−4 fringes corresponding to a refractive index resolution of ∼2×10−8. The long-term stability is about 1×10−3fringes×h−1 corresponding to a refractive index change of 2×10−7 h−1. The first design of the multichannel YI has four output parallel channels positioned at well-defined distances from each other, such that the phase shift between both channels of one pair can be monitored independently from the other channel pairs.