This paper presents a low coherence interferometer as a new interrogation technique of micro-resonator for biological molecules sensing. The spatial responses obtained with PS-OLCI setup are used to evaluate relevant parameters of micro-resonator design like coupling coefficient which allows to discern different coupling configurations. This setup, which is able to provide almost simultaneously the transverse magnetic and electric responses was used to evaluate the spectral performances of micro-resonator. The best performances were obtained on a polymeric racetrack micro-resonator when immersed in deionized water. This micro-resonator displays at 1 527.7 nm a Q factor higher than 38 000 and a finesse of 21. The association of the interferometric set-up and a polymer micro-resonator was allowed the detection of the concentration of glucose in deionized water lower than 5 µg·mL-1 for homogeneous sensing and the surface density of TAMRA Cadaverin lower than 4 ag·mm-2 for surface sensing.