For sensing applications measurement techniques based on interferometric arrangements typically provide higher sensitivity than direct measurement techniques. Can we demonstrate this on-chip, for the back-reflection measurement of various elements? Due to practical constrains the elements considered here are the ones readily available in SiEPIC Process Development Kit (beam dump, un-terminated waveguide or grating couplers). In a more realistic scenario, this experiment would measure the optical properties of bio-material or gas samples.
Designs placed on this fabrication run fall in two groups: design for direct measurements and designs using a Michelson type of interferometer. The direct measurement compares the back-reflection response over the 1500nm-1600nm wavelength range of two different components/samples from SiEPIC's library. Then, one pair of reference component is chosen and integrated to a Michelson interferometer arrangement. A second Michelson interferometer design allows a more direct comparison with the direct measurement.
Results will be compared to assess if one type of measurement leads to a better ability to resolve levels of back-reflection.